2nd gear TCC lock-up w/Westers re-flash ECM

[HANK1948]

When I called Westers wanting a 2nd gear TCC lock-up on my 96 reflash.
He said no problem as long as I want to be the guinea pig.

Well after returning the ECM back 3 times its figured out. The TCC locks up @ 21 mph on light throttle and stays there, its like driving a stick(direct engaugement) keeps the rpms low.

At WOT it stays unlocked like it should, and pulling my 30' gooseneck with 3 tractors on it, it will lock up early enough to give me pulling power and not lug the engine.

I havent figured out fuel milage but Iam sure it has improved, how can it not theres no slipage after 21 mph:D

[More Power]

In talking to the folks at BD while preparing a review on their 4L80-E Torq-Loc, they indicated the stock 4L80-E torque converter needs to be run with the engine above 1700 rpm when loaded hard with a locked TC. Lower engine rpm and a heavy right foot allows the individual torque impulses from the eight cylinders to hammer away at the locked TC. This can result in slippage that eventually takes out the TC clutch.

Jim

[Cowracer]

with my Heath chip, my TCC locks up tight just about anytime I get into OD. This helps tranny temps, but every now and then, it drops me to a flat part in the torque curve. A hundred extra rpm helps matters greatly.

I found that just brushing the brake pedal makes the TCC unlock, and I get the desired bump in rpm. I am looking into isolating the circuit that tells the ECM that the brakes are on, and maybe I can use that to make a 'forced unlock' switch for the times where you really dont want the tcc to lock.

If this works, someone could program the ECM to lock the TCC whenever possible, and you could use the 'forced unlock' to keep you out of trouble at low rpm.

Stay tuned

Tim

[JeepSJ]

Cow,

The circuit should be routed through your brake light switch under the dash. When you step on the brake, that switch interrupts the circuit. You should just be able to put a toggle on that circuit so that you can force the unlock.

[Cowracer]

Cow,

The circuit should be routed through your brake light switch under the dash. When you step on the brake, that switch interrupts the circuit. You should just be able to put a toggle on that circuit so that you can force the unlock.


Right. There is actually 3 circuits in the brake switch (IIRC) and I gotta dig out the schematics and figure out if I can trigger the right one without lighting up the brake lights.

Stay tuned.

Tim

[JeepSJ]

Right. There is actually 3 circuits in the brake switch (IIRC) and I gotta dig out the schematics and figure out if I can trigger the right one without lighting up the brake lights.

Stay tuned.

Tim

Yep. One is for the brakes, one is for cruise control, and the third is the lockup. They are all independent circuits so you shouldn't have any problems with brake lights when you are playing with the lockup circuit. My Waggy uses a GM style switch so I have the exact same setup.

[JoeyD]

In talking to the folks at BD while preparing a review on their 4L80-E Torq-Loc, they indicated the stock 4L80-E torque converter needs to be run with the engine above 1700 rpm when loaded hard with a locked TC. Lower engine rpm and a heavy right foot allows the individual torque impulses from the eight cylinders to hammer away at the locked TC. This can result in slippage that eventually takes out the TC clutch.

Jim

Could you just program it to lock up at 1700 rpm and higher no mater what speed

[Robyn]

JUST my 2 cents worth

After seeing the innards of the converter on a 4L80 I would highly recommend leaving the lockup do what it does with factory programing.
The clutch assembly is not near beefy enough IMHO to tollerate the high torque loads that folks are wanting to place on them.

The whole purpose of the TCC was to raise the highway mileage some by eliminating the excess slippage from the converter.

There may be a rebuilder out there that can and will build a converter with a better clutch but the only caveat is the amount of room inside the converter to do anything extra.

I would say nay to locking things in anything other than 3 and 4.

I have done it with a 6.2 that had the 700R backing it up but the little 6.2 is fairly benign when it comes to power so it was not an issue.

Another popular upgrade for the 4L80 is to eliminate the TCC completely and this allows the builders to use a heavier turbine and pump assembly that can transmit more torque.

Transgo sells a valve kit to use a non lockup converter

**Note** when pulling, if I feel the need for hydraulic drive I just sneek my left foot over and lightly touch the brake to release the TCC
Done that for years.

Best

Robyn

[DA BIG ONE]

While the stock convertor cluch maybe lacking there are many options from kevlar to ceramic then some builder would make a multi disk unit if you got really deep pockets.

[Robyn]

The one issue that is overlooked when focusing on the TCC is the fact that all that material takes up space inside the conveter and this detracts from the available room to place important parts like the turbine, pump and stator assemblies.
The 4L80 does not really have enough room in the bellhousing to make the converter any larger to speak of.

With the TCC left out there is a lot more room for a more beefy turbine and pump assembly as well as a larger more robust stator.

With larger parts the converter can be more effecient and although the lockup feature would be gone the overall package is tougher and will handle the power better.

I have seen the multi disc TCC assemblies and they do work well.

I believe the Allison uses this sort of set up.

I still do not like the idea of locking the TCC at low speed as it defeats the whole purpose of the converter.
Having the ability to use a locked converter for engine braking is nice though.
My 84 Blazer was that way after I built the 700R and tricked it out.
I hated the low speed lockup though so I rarely used it.

Too much driveline growl and rumble untill the road speed was over 40 under a load.

Later

Robyn

[HANK1948]

The problem with no lock-up is if your towing a big load up a long grade the trans temps go though the roof. I can watch my trans temps drop 50 deg once the TCC locks up.