B&M Shift+ Shift Improver Explained [Archive]

TurboDiverArt

02-11-2004, 18:11

Looking at the Interceptor that John sells and reading other information about it on the web it seems to me that it's installed on the transmission? Are the controls in the cab?

Hell, I'll pay 4 times the price if I can get what I want. If I'm going to pay 4 times the price, or 5-6 times the price for the BD unit, I'd like something that will:

Work on a 1999 truck
Increase line pressure
Lockup TCC in 2nd
Have adjustability as to when the TCC locks up in each gear.
Having a delay to TCC I guess would be nice, I'm just not sure why exactly.

Art.

S\W Off Road

02-11-2004, 19:13

Originally posted by GARY PAGE:
This is may be what Heath Diesel is selling for $129.00 at 4 times the price, rip off.
Heck if it's the same, Sort out the rats and make them get in line!
J.Kennedy is selling his for $129. also, could it be the same as what Heath Diesel has?

GARY PAGE

02-12-2004, 15:37

Don't know all someone has to is state the connections that are invloved ie.. C11 on xx model PCM or pins ... on the 4L80E tranny etc.. and we can figure out what it's controls. That's not to say it's not worth the money your paying cause your paying for an Idea not the material. The difference is that B&M has a much larger market and it covers the R&D so they can sell for less.

Kennedy

02-12-2004, 19:09

The Interceptor plug into the transmission harness and is fully adjustable.

ACTUALLY, I put a little bit of psi on the chip programming which generally fills the bill quite nicely.

TurboDiverArt

02-12-2004, 19:21

Originally posted by kennedy:
The Interceptor plug into the transmission harness and is fully adjustable.

ACTUALLY, I put a little bit of psi on the chip programming which generally fills the bill quite nicely. Hey John,

Is the transmission harness under the chassis or in the cab?

Thanks,
Art.

Kennedy

02-12-2004, 19:46

Right at the transmission body.

TurboDiverArt

02-13-2004, 02:46

Thanks for the clarity John! No reported problems using the Interceptor on a 1999? Seems that the B&M unit (might) as well as the BD AutoLoc unit have problems with the newer trucks.

Still waiting to hear if anyone has tried a B&M ShiftPlus unit on a 1999 since the web site says 94-98 only.

Art.

Scottpearce

02-13-2004, 14:07

It works as advertised on my 93 also, so 94-98 doesn't seem to be exclusive to the improver. :cool:

rjwest

02-13-2004, 15:38

Gary Page: I have been studying post and have a few questions. ( Great Info by the way. )

I am trying to get TCC lock up in 2nd and at lower MPH, Problem is both the BD torque loc and the
Resister in Thermister line method cause TOO HIGH shift pressure ( I Think ).
Shifts very severe.

As I understand from post the Pressure control solenoid is controlled internal to transmission
to a set value and the PCM has no function under
normal driving parameters. IE pins C11 and C6
are " effectively open " internally in PCM and no current is being shunted.
Therfore If I were to disconnect one of these pins
The PCM could never raise the Line Pressure?

Now If I switch in the HOT Mode Thermister,
causing TCC to lock up in 2nd 3rd and 4th and at
a lower MPH ,even though the PCM would command
Higher Pressure it could not due to line being open.?

I assume the only function that would be lost would be the SLIP Learn/Higher Pressure Adjustment

Last Question. Does the JK, Heath , or B&M
efectively open the C11-C6 Pins and replace with a controled set of resisters or just parallel them with a resister value..?

I was considering a TCI stand alone Transmission Controller, but another 800 dollers is a lot to spend. But I am like Turbodriverart, would like the damn thing to lock in 2nd

Thanks for all the info....

GARY PAGE

02-14-2004, 03:58

Shunting current away from the pressure solenoid means less current to it. Look at the table again real close. If you open the circuit to the solenoid, current is going to zero and the pressure is going to max, it will hit hard. I may have confused you when I indicated the B&M unit in the normal setting was an open circuit across C11 and C6. May be I should have said

GARY PAGE

02-14-2004, 06:28

This is what I am looking at...hope it helps...

http://home.comcast.net/~garsu/4l80e1.jpg

gmctd

02-14-2004, 06:43

TCC control is by digital pulse width modulation, which is why there are no actual 4L80E TCC lockup devices available, aftermarket - B&M, TCI, etc.

PCM signal is a frequency of ~30hz, so simply grounding the pin will damage the TCC Solenoid, and probably the TCC, as well.

rjwest

02-14-2004, 07:24

Thanks all, Found my manuels, Wife cleaned house, put all my things away first.........

OK, I think I am begining to understand....

PCM is required to control Solenoid to prevent harsh shifts. How do the shift improvers work,
Can they only " Firm shift and not " Soften "
shift?

With a Aftermarket controler installed, If PCM
demands FIRM/HARSH shifts due to codes etc.
will it over ride external Solenoid controller settings?

With an external controller installed is the PCM still functioning to control Pressure but at a different level?

Sure wish I new, Need that 2nd gear TCC.

GMCTD, I figured out the TCC Differance when I bought a Torque-Loc. Still have the useless thing.

gmctd

02-14-2004, 07:52

Firm setting, PCM calls for Firm, you'll get even firmer shifts.

Firm setting , PCM calls for Soft, you'll get softer than firm shifts.

The switched resistor is just a current sink, diverting power from the Pressure Solenoid.

Regarding the Tork-Lok, could be helpful if you would list the all connections required.

GARY PAGE

02-14-2004, 10:31

Hey gmctd your probably right on, that

MTTwister

02-14-2004, 13:12

Gary - In the table - could you clarify the !st line of current - pressure? Guessing s/h/b/ .02amps.

Now - If you use the Cheap way to get the TCC to lock up resistor - you effectibely put the tranny in "Hot Mode" - and it increases line pressure for shifts. ( my understanding).

SO - IF you were to use this table, and add resistors to Reduce the Line pressure called for, could you soften the harsh shifts called for under the Cheap TCC lockup thread?

Or, Does Hot Mode ignore PCM input?

BTW, what watt resistors would we be looking at here? ( ie 11v * .9 amps = 9.9 watt resistor? ) or is the resistor carrying the Difference between the full 'signal ' ~ 2.2 amps - 'required' amps. then that would be 2.2-.9 = 1.3 * 11v = 14.3 watt resistor? That doesn't seem 'right' - but I don't do electronics ( good thing) .

OK - rip it up, guys!

gmctd

02-14-2004, 13:43

The TCC clutch may not have enough surface area to transmit full engine output torque - probably would not even help to have kevlar linings installed.
That's one of the reasons why the TCC releases at mildly aggressive accelerator input in 4th O\D, rather than raising pressure to firm-up application.

You may note the gasoline engine versions do not have 'Hot Mode' capabilities - has to do with exceeding 'allowable slip' design limits.

One reason may also have to do with the hollow input shaft, required for pressurized fluid to actuate the TCC piston.

Back in '64 ~ '69, GM Hydramatic Division offered the Super Turbine Hydramatic, a three-speed automatic forerunner to the T-400, in B-O-P lines.

Called the 'switch-pitch' it had a piston in the torque convertor, similar to the 4L80E TCC, which varied the angle of the stator from low stall to high stall. Very imaginative - gave a heavy car more oomph off the line, and could be used as an effective passing gear.
Required pressure was electrically activated via throttle-mounted switch to internal solenoid.

The street racers (I never participated in this group) and professional drag racers snapped them up in a heartbeat - high stall off the line, switch to low stall at about 5k rpm gave excellent advantage over other brands cars running in automatic classifications.
Adaptor plates and such were designed for the 'other' marques.

Only one problem - the hollow input shaft, required to supply fluid to the stator piston, would break under high-power application. Very disastrous, as suddenly unloaded engine rpm screamed up towards 5-digit numbers.
We're talking 426's, 427's, 430's, 454's, 455's - long-stroke motors never meant to get much above 7500 rpm in street form.

I'm thinkng pretty much the same fate for the 4L80E, where accel-decel torque would work-harden and break a hollow shaft, supposing the TCC were hard locked up, as in the 4L60 versions.

GARY PAGE

02-14-2004, 14:29

Yes slight of hand, sorry, age does that to you, good eye:
20 mA amps 170-190 psi

rjwest

02-14-2004, 14:44

I had an 80 Diesel,( 100k trouble free miles)

It had a Lock Torque converter ( lock at 27, unlock
ay 25 mph ) It would not unlock at considerable
throttle setting, I soon learned to " feather the throttle or manual shift to 2nd , But had no other complaints, Wish my 96 was that reliable.

1 last try at poor mans TCC ock up:

If a resister in series was added to Pressure control line when HOT mode selected, would this
lower line pressure back to normal,

I realize limits of TCC , and exposure to slip,
USER BEWARE, I just don't think 2nd gear will exceeded TCC limits in normal driving.

I wish I knew of someone that has installed a TCI transmission controller, May try it (800$ ?
maybe not).

gmctd

02-14-2004, 15:52

Reduced pressure requires increased current, so - no. Adding a resistor, parallel or series, will reduce current, increasing pressure.

IIrc, the DP 6.5 Project Truck used an aftermarket version of the factory oem stand-alone 4L80E TCM.

Available in '91 to '93 trucks with a 4L80E trans, the oem version was specific to that early series.

I'm still fairly positive that second-gear TCC lock-up will eventually break the input shaft due to increased accel\decel torque.

And that's the third reason, in my opinion, GM opted for a non-hard-lockup TCC, as in the 4L60E, and such.

And removed the option of the 4L60E from the Diesel lines.

MTTwister

02-14-2004, 16:28

I'm Back - Problem - If the tranny goes into Hot Mode, and the PCM cuts current to "~0" for Full Line pressure, How are we going to ADD current back in to get the current back in to .4 'ish?

I can't imagine that installing a resistor in Series do the trick? BWDIK!

Edit - Oh - User's will be responsible for only using this manually in 2nd, maybe third when 'needed'! tongue.gif Leaving on at all times will void 'warranty' ! redface.gif

rjwest

02-14-2004, 18:20

ok. I give up, Time for a Cummins Std shift

gmctd

02-14-2004, 19:04

Careful there, MTTwister - sounds like you're well on your way to becoming a amachoor electronic tech! ;)

Far as the 4L60E's, they were only offered in the n\a and EGR turbo trucks, where the TDC Offset was factory set to -1.5deg for mid-range horse power, but which decreased low-end torque.

TurboDiverArt

02-14-2004, 19:04

Originally posted by gmctd:

<<SNIP>>

One reason may also have to do with the hollow input shaft, required for pressurized fluid to actuate the TCC piston.

<<SNIP>>Not that I'm a mechanical engineer or play one on the Internet. I thought with torsion strength (think that's what it's called) that the vast majority of strength, like 90% or so was found in the outer 10% of the shaft. Meaning that a solid shaft is only marginally stronger than a hollow one when if comes to twisting strength. That's why on the newer performance cars like the Camaro's they started using a hollow front sway bar, have less weight and the same performance with only a slightly larger diameter bar. Maybe the slight additional strength that a solid input shaft would give over a hollow one is just enough to keep it from snapping. Just a thought. Probably better to replace it with a hardened one if someone makes one if you ever have to pull the trans.

Art.

TurboDiverArt

02-14-2004, 19:09

Originally posted by gmctd:
Firm setting, PCM calls for Firm, you'll get even firmer shifts.

Firm setting , PCM calls for Soft, you'll get softer than firm shifts.

The switched resistor is just a current sink, diverting power from the Pressure Solenoid.

Regarding the Tork-Lok, could be helpful if you would list the all connections required. JD,

Would you know if for any reason the B&M ShiftPlus would not work on a 1999? B&M doesn't list 99 as an application year. Wondering if you know of any reason that it wouldn't work. Based on Gary's description of how it works it's just putting a resistor across 2 wires on the PCM. Would using it cause a code? At the price of $45 or so for it I

gmctd

02-14-2004, 21:45

Art - anti-sway bars are essentially torsion bar springs, meant to provide some resistance in twisting.

The transmission input shaft is usually meant to transmit torque with minimal or no twist.

Some trans shafts are meant to absorb shock loading by twisting within designed torsional limits.

Light-duty, throw-away type automotive transmissions have had hollow shafts (usually of foriegn manufacture - Fiat, Renault, etc) but trucks in general require thick, solid shafts, usually case-hardened to resist wear and twist.

The 4L80E input and stator shafts were enlarged over the T-400 (3L80) assys, but not, in my opinion, enough for the hollow input shaft to resist accel\decel shock of the locked up TCC, particularly in second gear.

Not much decel in Diesel applications, but the trans was used in HD 454 gas apps, also.

I'm basing this on the modulated TCC apply system, and designed 'acceptable slip' parameters in the PCM.

Normally, in the past, GM has done this type of thing so trans shifts would not jar the old folk's dentures. Not much sense for it in a truck series designed for heavy loading\towing.

I'd like to look at a B-D Tork-Lok, for further info. My truck has the 3L80, so it would be for inquiry, only.

Having no specific knowledge as to PCM differences between '96-'98 and '99 4L80's, I would not try the pressure solenoid current shunt on the '99 trans, if B&M doesn't list the application.

rjwest

02-15-2004, 07:46

GMCTD, If you want to use a BD torque loc to
try out I'll lend you mine.....It's sitting in a box...doin nuttin

gmctd

02-15-2004, 11:20

Thanks, rj - I've noted that in my memory banks, and may take you up on the offer at a later date.

For now, if you would post the wiring and connection specifics, it could be very helpful in determining whether or not I actually need to see the box, itself .

Copyright considerations may prevent posting the actual sheet, but the hook-up data, in your own words, should pass muster.

rjwest

02-15-2004, 15:11

GMCTD Im at rjwest@attglobal.net
If want to email me I will scan the wiring diagram
and send it to you., whats in the black box
is not published...

gmctd

02-15-2004, 18:51

Ok, but hold that thought, rj.
And, again, thanks.

I just read ronniejoe's article, and got the connections from that.

It's power, ground, VSS input, and control is series'ed into the PWM TCC solenoid circuit.

gmctd

02-16-2004, 10:12

rjwest, which VSSB wire - dk green or green\white stripe - did you connect to your BD controller?
And, what DTC(s, if more than one) was set?
TIA

rjwest

02-16-2004, 14:02

Gotta check on vssb,wire.

I only got a code once, TCC stuck on

But just about every time i used it I got
no codes, But HARD SHIFT'S, Very Hard....

If I used it in 2nd on a climb and shut it off
before lifiting throttle It was ok,
But Than Lost all that speed and up shift still not smooth.

I think it works ok on pre 96 ( obd1) There is
someone on DP using it on OBD2, I think he's mastered the tricks of On/Off sequence.

Will pull glove box and check wire tommorow....

It sure drove nice at 35 mph with lock up.
no throttle at all to maintain speeds in town.
I think fuel milage would go up.

Question. What year did GM start using 80LE?

What did they use for a controller in early years?

gmctd

02-16-2004, 15:02

4L80E was offered in '91 old style Subs, and new body style to at least '93 (vans, maybe later) with stand-alone TCM. It is the same unit Jet, TCI, and others sell.

Would take a call to them to see if aftermarket units are modified for lockup and pressure, tho.

rjwest

02-17-2004, 08:14

GMCTD,thanks.

VSSB at PCM(96 obd2) dk grn pin A6(24pin brn con)

TCC at PCM BRN pin C5 (32Pin Blu con)

I wonder how hard 1 of those stand alone controllers
would be to find and adapt to obd2 truck.

my goal if i keep this truck is to get
rid of Electronic pump and to get 2nd gear tcc
with reasonable Lock MPH.

would be nice to get rid of the intire OBD2

gmctd

02-17-2004, 13:38

That would require '93 TCM, your VSSB, '93 harness, and the '93 APP\TPS as installed on the DB2-4911 Inj Pump, all oem factory.

Some modification to the 4L80E electricals was done around '94, so call Jet, TCI, or whomever for details to match up what you got with what you get.

Some of this has been done already here on the DP, so perhaps a 'search' would turn up specifics.
The DP Project 6.5TD truck has been there, done that, as have others.

Thanks for the info - I'm doin' some figgerin', again!

MTTwister

02-29-2004, 10:31

Going thru the '96 manual, trying to figure this out.. Here's maybe why CHIT don't work for '96 and up.
Going to try and make sense of my research by cutting and pasting...

[i]In the normal setting

HowieE

02-20-2005, 07:16

gmctd

Another vioce with some input that hopefully will allow someone to solve this problem.

I have a BD Torq Loc on my 1997 4L80 and have suffered with it from day one. I have met with the fellow that designed it for BD and even though he originaly thought he could come up with a solution Brian Roth advised me that BD was no longer supporting that product. That was 3 years ago.

On my installation the Torq Loc will set Limp Mode if I accelerate through the gears while the Torq Loc is on. Lime Mode is line pressure of 125 psi and the hard shifting everyone mentions.
However if I use the Torq Loc as a manual system I have found it usefull while towing. When starting off under load I will accelerate to about 35 mph with the trans set in 3rd. at 35 mph I will set the TL to green mode and the TCC will lock. I continue to accelerate to about 55 mph and then, a point at which the TCC is commanded locked by the PCM, release the TL and shift into 4th and then set the TL in red mode, the setting that will hold the TCC locked at speeds above 50 and down to about 35 mph. This method works well to keep the trans temperatures down and allows full use of my exhaust brake. The problem is I have to remember to open the TL system when the road speed again drops below 50 mph because any reacceleration from speeds below 50 mph will set Lime Mode.
In areas where I will be traveling at speeds below 55 mph, in town or country roads, I will just stay in 3rd and have the TL set in the green mode. No problems have ever occured while in this use.
Not what I paid for but.
The Speed sensor on the TL input is connected to the dark green wire on my istallation.

99gmccrew

02-20-2005, 22:10

Turbodiver, I bought the B&M shift plus electronic controller and it does not work for my 1999. :( I went with the B&M shift kit (the kind you drop the pan to install) and that did work and I'm getting much crisper shifts. ;)

99gmccrew

DA BIG ONE

02-21-2005, 04:03

I'm running a TransGo offroad/towing valve body mod, set to shift hard and quick however, my ECU resets it bringing it back to a soft shift.

It is a Heath setup w/stock trans program. My transmission is built w/just about every mod that can be had for it, so Bill suggested staying with the stock tranny settings. So, far no problems.

gmctd

02-21-2005, 05:36

Wow - this is from a year ago - I've slept some, since then......

While beating my head about the TDC Offset thing, I had completely forgotten about this topic, as I do not have the 4L80E trans in my truck.

There may be an expensively viable solution to this.

Get the manual transmission PCM, which will manage the engine, alone.
Engine harness termination is the same, year-for-year.

Get the TCI or etc 4L80E stand-alone TCM, which will manage the 4L80E.
Also get the control harness, unless capable of extracting the transmission control wires from the auto PCM connectors.

One output from the APP module should function as TCM accelerator input, by connecting the PCM ground to the TCM ground, and the APP variable signal to TCM input.
PCM will supply Vcc power to APP

Use the B-D or other shift-management black box to 'enhance' your driving\towing experience, without setting EFI Limp Mode.

Big caveat, here - I'm fairly certain Turbohydramatic Div utilized TCC 'soft apply' mode to protect the hollow input shaft and stator shaft for Diesel\454 service, and to prevent breakage from accel\decel torsional reactive.

[ 02-22-2005, 05:35 AM: Message edited by: gmctd ]

rjschoolcraft

02-21-2005, 06:39

Originally posted by gmctd:
I'm thinkng pretty much the same fate for the 4L80E, where accel-decel torque would work-harden and break a hollow shaft, supposing the TCC were hard locked up, as in the 4L60 versions. Work hardening requires plastic deformation and involves a packing (or squishing) of the microscopic grain structure of the material. I doubt very seriously that work hardening is going on.

What is more likely is a fatigue failure that originates from some imperfection at the surface or some fillet radius that is too small. Reverse torque (although this case is not fully reversed) can reduce the safe load by 30%.

Originally posted by TurboDiverArt:
Not that I'm a mechanical engineer or play one on the Internet. I thought with torsion strength (think that's what it's called) that the vast majority of strength, like 90% or so was found in the outer 10% of the shaft. Meaning that a solid shaft is only marginally stronger than a hollow one when if comes to twisting strength. That's why on the newer performance cars like the Camaro's they started using a hollow front sway bar, have less weight and the same performance with only a slightly larger diameter bar. Maybe the slight additional strength that a solid input shaft would give over a hollow one is just enough to keep it from snapping. Just a thought. Probably better to replace it with a hardened one if someone makes one if you ever have to pull the trans.

Art. Art, you're right on the money here. Making a shaft solid will increase its lateral stiffness, but will not significantly benefit its torsional stiffness as compared to a properly designed hollow shaft.

For the record, I have over 46,000 miles on my TorqLoc installation. I use it for accel/decel in 2nd - 4th ranges when towing. So far, no problems.

moondoggie

02-21-2005, 09:43

Good Day!

gmctd, re.: Hollow input shaft: If a driver made sure to NEVER allow the tranny to shift with TCC locked in 2nd, is it possible the input shaft could stand up to the steady-state torque of climbing a hill? In other words, is it the massive "twang" of a shift that would be a problem for the input shaft, vs. steady-state hill-climbing torque?

on edit: Sorry Ron, somehow missed your post B4 posting this. I'm going to leave it anyway - this kind of technical discussion by folks that know what they're talking about is GREAT!

TIA & Blessings!

Brian Johnson, #5044

gmctd

02-21-2005, 11:49

My thinking is work-hardening in the splined area, where applied engine torque and engine-braking apply opposite compressive stresses to the shaft splines.

Per your suggestion, Brian, the difficulty would come in not applying TCC lockup on down grades, while down-shifting as necessary, to provide constant engine braking assistance.

Same scenario in 454 trucks, where engine vacuum results in hi-torque deceleration in engine-braking events.

4L60E TCC is\was direct lockup type - 4L60E was discontinued in Diesel pickup lines around '95-'96.

The shafts break at the splined area, either end of the shaft.

Could also be undercutting - probably take some destructive testing to confirm, but other shafts and drum\clutch-pak splines from same transmissions also evidenced
apply\reverse braking-apply damage to splines.

4L80E TCC is released at braking events - notable is that TCC is also released at any off-throttle deceleration event.

4L80E TCC is modulated for specific reasons.
Could be the input shafts - could be the TCC cannot handle the load.

You decide - but, it is modulated for torque loading, and PCM monitors input\output rpm ratio for acceptable slip.

[ 02-21-2005, 12:22 PM: Message edited by: gmctd ]

rjschoolcraft

02-21-2005, 12:31

I'll say again...

Work hardening is not happening here. Cyclic fatigue, yes. Work hardening, no.

Maybe I've been lucky, but I've never even heard of breaking 4L80E input shafts before getting involved in this site. I allow mine to shift with the TorqLoc engaged all the time. The transmission has 224,000 miles on it and has not been touched. I posted earlier the number of miles since the TorqLoc was installed.

Kennedy commented once about dual stator torque converters being the problem with input shafts. Seems the sudden shut down characteristics of the diesel engine caused rapid high torque reversals between stators that was rapidly fatigueing input shafts. Mine has a single stator in it and I doubt that you will find many dual stator converters anymore.

In the time I've been involved with The Diesel Page, I've not heard of a single, first-hand, recent failure of an input shaft on a 4L80E transmission.

I'm also beginning to believe that if anyone were going to break one, it would be me. smile.gif

Another engineer once said to me, "I found him!"

I said, "Found who?"

He said, "That worst case. I've always wanted to find that worst case guy, and I think I've just met him!"

This came after I showed him a speed shift in an 84 Cavalier 2.0 4-cyl that chirpped the tires in second. :D Wasn't too long till I was putting a clutch in that thing. Dang piece of junk. ;)

gmctd

02-21-2005, 12:49

I am undoubtedly using the wrong terminology, as cyclic fatigue would seem to be more descriptive.

I don't have a 4L80E, so I cannot be absolutely sure, but I do not think the TCC is actually 'locking up' with the Torque-Lock and other add-ons.

Only the 'apply demand' event is being altered to maintain apply where 'release demand' is set.

The DTC problems with Torque-Lock and the PCM may be solved by a PCM with separate TCM, but I would not advise 'switch'-locking the TCC in that case, either.

rjschoolcraft

02-21-2005, 13:05

Originally posted by gmctd:
Only the 'apply demand' event is being altered to maintain apply where 'release demand' is set.
I think that statement is true, based on the scans I've looked from my ALDL.

The highest I've seen is about 98% on the TCC apply solenoid duty cycle. There is always a little bit of slip through the clutch.

AndyL

02-21-2005, 13:33

Originally posted by DA BIG ONE:
I'm running a TransGo offroad/towing valve body mod, set to shift hard and quick however, my ECU resets it bringing it back to a soft shift.

It is a Heath setup w/stock trans program. My transmission is built w/just about every mod that can be had for it, so Bill suggested staying with the stock tranny settings. So, far no problems. Mine does the exact same with the B&M shift improver, it seems that something (ECM?) has, learned, and it now shifts soft again.

moondoggie

02-21-2005, 15:08

Good Day!

[i]gmctd said,

gmctd

02-21-2005, 18:41

Actually, your skills are quite excellent, Brian. I was at work, and was rushed - that should have read "per your question", but I did not correct all of the several glaring errors and proof-read it after it was in Forum format.

I had suggested a scenario where 4L80E DTC's which would trip the PCM into Limp Mode could be avoided by utilizing seperate engine and transmission control modules.

The Torque-Lock has been sucessfully used in towing service by several members, incl ronniejoe, HowieE, Tanker(?), and etc.

The TCI\Jet\equiv stand-alone TCM has been successfully used by several members, incl Jim MOREPOWER Bigley, and iirc the guy with the Ferrari emblem (sorry - icon stuck, but not the handle).

Problem is, if the PCM is happy, then the TCM DTC's could pose little problem, and could (possibly) be ignored.
Leading, of course, to the TCC controlled by a switch, rather than PWM soft-applied.

"'At blinkin' lite rat t'ere, Myrtle? 'At's muh Daytime Warning Lite - let's me know muh tranny's on th' job, and pullin' hard!" ;)

I've always installed increased-duty shift kits, run hi-stall or lo-stall convertors as required, wired-in TCC lock-up switches to the 4L30 and 4L60, so I'm often approached for a switch - or a control circuit, when I explain 'not switchable' - for the 4L80E.

What I understand from all this says Caution.

If combined with compression braking, Caution says No.

So,(at long last) to address your question, Brian - the question indicates locking for applied power, and down-hill braking, which is a big part of traveling\towing, only after trans is completely shifted into a specific a gear range.

If you have not, do a 'search' to read the local reviews here and on the towing forum.

The several shafts take a lot of torque when towing loaded, with more shock-loading when the truck is being hot-rodded thru the gears (and a lot of folks are discovering a real Diesel hot-rod, when tweaked).
But they take almost no reverse-loading, with the unlock-on-decel program, and virtualy no compression braking.

So, you might also check the Chevy\GMC gasser forums, noting any input specific to the 4L80E\454 equipped rigs, with inherent hi-reverse-torque compression braking.

What you will be looking for is any associated problems, including any altering or defeating of the PWM unlock-on-decel TCC system, and the results.
Successes should also be notable.

You should be more comfortable with a decision based on real-world application success or failure, don't you think?

[ 02-21-2005, 05:53 PM: Message edited by: gmctd ]

Peter J. Bierman

02-22-2005, 13:29

To solve my 4L80E control problem, I bought a PCS controller and got it this weekend.
It will take a wile before I actually use it but did take a look in the software that came with it.

WOW! everything is programmable, even the type of switches you use for some functions.
This realy take transmission control to the next level! :D

Down side however is that now you have to realy study the transmission and what it does, and have to come up with all kinds off data to program :confused:

I start learning today by reading this post and the PCS manual and cook up something to start with and trail and error fine tune from there.

I'm exited about the possibilities this unit offers and will let you know my findings.

Peter

DA BIG ONE

02-23-2005, 02:44

Originally posted by AndyL:
</font><blockquote>quote:</font><hr />Originally posted by DA BIG ONE:
I'm running a TransGo offroad/towing valve body mod, set to shift hard and quick however, my ECU resets it bringing it back to a soft shift.

It is a Heath setup w/stock trans program. My transmission is built w/just about every mod that can be had for it, so Bill suggested staying with the stock tranny settings. So, far no problems. Mine does the exact same with the B&M shift improver, it seems that something (ECM?) has, learned, and it now shifts soft again. </font>[/QUOTE]Bill, suggested my tranny was already overbuilt its task, and going w/different tranny flash may verywell result in some unwanted problems. Got about 15,000 miles w/towing and w/o since all the work and happy with it.

However, when my IP goes then a marine mech IP will replace it along w/standalone tranny controller.

moondoggie

02-24-2005, 06:27

Good Day!

gmctd: Thanks! ;) I mostly ask questions like this because the subject is technically interesting, plus others (who might actually be considering this) will profit. It's very unlikely I'll ever be in a position to fool with my tranny control. :(

As always, very grateful for the very informed input from you & the others like you. (I won't mention names, for fear of offending someone not named - you experts know who you are anyway.)

Blessings!

Brian Johnson, #5044

gmctd

02-25-2005, 04:23

Thanks, Brian.

I always keep in mind the release-on-decel program for the TCC - Hydramatic Div used this function on all the hollow input shaft transmissions.

Any loaded vehicle requires engine-braking during decel, so removing that function in a transmission designed for light heavy-duty trucking would seem self-defeating.

In light of that, release-on-decel would appear to be more of a mechanical self-protection scheme, relieving accel\decel\accel shock-loading, imo.

2500\3500\454\4L80E and towing forums would be real-world application-specific indicator.

And, a very good day to you..........