Diesel Governor Recommendations

[AugustDiesel]

So my new 700r4 has a gas governor in it, which is throwing off my shifting points. Looking for a diesel governor to replace it with, any recommendations on brand/where to buy?

1988 K10 suburban with a Goodwrench 6.5, fullfloating 14 bolt rear and 3/4 ton 10bolt

[Robyn]

Try this

http://www.ebay.com/itm/GM-THM700R4-4L60-Sonnax-Governor-729-f-Diesel-Engines-1982-1993-Chevy-Buick-GMC-/321905478139?hash=item4af30fc9fb:g:LPsAAOSwvg9XWb6 6&vxp=mtr

[AugustDiesel]

Try this

http://www.ebay.com/itm/GM-THM700R4-4L60-Sonnax-Governor-729-f-Diesel-Engines-1982-1993-Chevy-Buick-GMC-/321905478139?hash=item4af30fc9fb:g:LPsAAOSwvg9XWb6 6&vxp=mtr

Thanks Robyn! I had seen that already just didn't know anything about Sonnax and their quality. But I'll give it a shot!

[AugustDiesel]

So, it seems to be a success. Prior to the diesel governor, it wouldn't shift from 1-2 until 26mph, 2-3 at 35mph, and 3-4 at 40mph. Now that the diesel governor is installed, it actually seems to shift earlier (doesn't seem to be a bad thing): 1-2 is at 10mph, 2-3 is at 20mph, but then 3-4 isn't until 45mph, and it seems to hold 4th really well vs before it wouldn't. Trans temp stayed right at 200 degrees, which is warm, but maybe not considering it's 95 degrees here in north Florida. No leaks anywhere, and it moves through the gears pretty well and fasts too.

[AugustDiesel]

So it seems, after a few test drives, I may not be out of the woods yet. While the shift points seem to be okay, the trans does not seem to want to down shift when getting on the throttle. Particularly in highway speeds, if I'm already in 4th, I can play with the pedal a bit to get it to downshift to 3rd, but even then, once I slam the pedal (for either passing other vehicles or climbing uphill) it just pops right back into 4th gear and bogs down. Any ideas on the cause of this?

[convert2diesel]

Tis the nature of the beast. Without the control afforded to electronic transmissions, the older mechanical trans, needed that governor to keep the engine speed below the governed RPM (3,200 to 3,500 RPMs). The intent is to keep the RPMs as close to 2,000 as possible.

Takes a bit of getting used to as far as driving is concerned but the neither the 6.2 nor the 6.5 were ever envisioned as hot rods. Keep it calm and it will live a long and reliable life.

Bill

[JohnC]

Sounds like you need to adjust the TV cable.

[DmaxMaverick]

Shift points can be affected by more than just the governor. More often, it's the fuel filter (really), or a TV (Throttle Valve) cable out of adjustment. The fuel filter is as easy as a change. The TV cable needs to be adjusted properly or it won't shift properly, and can damage the tranny. First, be sure the skinny pedal is actually allowing for full throttle travel. Mash it to the floor and check for limit of travel at the throttle on the IP. Next, calibrate the TV cable. Make a note of the length of bare cable exposed. Press/squeeze the button at the TV cable bracket nearest the IP. This should allow the cable to retract. If it doesn't, it could indicate a failure of the TV inside the tranny, or a damaged cable. Once it's retracted, mash the skinny pedal to full throttle travel. Measure the exposed cable again, and compare it to your previous measurement. As little as 1-2mm can make a significant difference.

[convert2diesel]

Shift points can be affected by more than just the governor. More often, it's the fuel filter (really), or a TV (Throttle Valve) cable out of adjustment. The fuel filter is as easy as a change. The TV cable needs to be adjusted properly or it won't shift properly, and can damage the tranny. First, be sure the skinny pedal is actually allowing for full throttle travel. Mash it to the floor and check for limit of travel at the throttle on the IP. Next, calibrate the TV cable. Make a note of the length of bare cable exposed. Press/squeeze the button at the TV cable bracket nearest the IP. This should allow the cable to retract. If it doesn't, it could indicate a failure of the TV inside the tranny, or a damaged cable. Once it's retracted, mash the skinny pedal to full throttle travel. Measure the exposed cable again, and compare it to your previous measurement. As little as 1-2mm can make a significant difference.

All very valid but when I did the Buick conversion, I went through the same issues as August is going through after swapping out the governor. Got thoroughly frustrated trying to correct the TV cable and finally did it using a line pressure gauge, only to find I had adjusted it correctly.

Turns out the previous owner had also installed the infamous "Corvette Servo" and combined with the new governor, the result was the 4/3 shift would only happen at 3/4 throttle and a 3/2 shift would only happen with the skinny pedal mashed to the floor. Suited me fine as with the gears I had, anything over 50 MPH and 2nd gear would take it up to the engine governed RPM and stay there until I backed off the throttle.

All was made more tractable when I finally replaced the torque convertor with the required 1,200 stall version. The combination lasted over 100K miles with no trans issues.

Bill

[AugustDiesel]

All very valid but when I did the Buick conversion, I went through the same issues as August is going through after swapping out the governor. Got thoroughly frustrated trying to correct the TV cable and finally did it using a line pressure gauge, only to find I had adjusted it correctly.

Turns out the previous owner had also installed the infamous "Corvette Servo" and combined with the new governor, the result was the 4/3 shift would only happen at 3/4 throttle and a 3/2 shift would only happen with the skinny pedal mashed to the floor. Suited me fine as with the gears I had, anything over 50 MPH and 2nd gear would take it up to the engine governed RPM and stay there until I backed off the throttle.

All was made more tractable when I finally replaced the torque convertor with the required 1,200 stall version. The combination lasted over 100K miles with no trans issues.

Bill

So here is what I discovered during my tv cable adjustments: During the above-mentioned shifting patterns, the tv cable was pulled all the way out, resulting in the 1-2 shift at 10mph. So, I push it all the way in, which results in a 1-2 shift at 26mph. Way too high. So, I set the tv cable halfway, and it gives perfect shift patterns: 1-2 at 15, 2-3 at 25, and 3-4 at 50. Not only that, but during an uphill climb on a long STEEP bridge (Jacksonville, FL), with the pedal all the way to the floor, it down shifted to 3rd gear and not only maintained speed, but gained speed during the uphill climb.

Me thinks this is a good sign, except once I get over the bridge and exit the highway, come to a complete stop, now the shift patterns have changed to 1-2 at 27, 2-3 at 45, and 3-4 at 65mph!! I pull over, check the tv cable, STILL in the same position I set it in before the test drive. Just took it on a short drive around the block after letting it cool off, no change, 1-2 is still at 27mph. What's the deal?

I should mention that shortly after the transmission install, one of the cooler lines failed, blowing out all my transmission fluid while driving down the highway (which led to me rebuilding all my lines). My transmission builder is recommending I drop the pan and see if there was any damage. I certainly will if it comes to that, but I have not seen or smelled any burned fluid or black stuff in the fluid when pulling samples from the drain hole in the bottom of the pan.

Thoughts?

I'll also add that my 700r4 also has the corvette servo. In fact, here's the build list:

5 pinion front and rear planetary gears - factory GM parts
Beast Sun shell - thick billet steel
Corvette servo
New band clutches bushes seals washers gaskets
10 vein pump rotor
Drilled out plate
New sprag
K case

The tv cable is the original not a new cable

Thanks in advance for all the feedback. It's been very helpful!

Andy

PS- I'll also add that during that uphill climb when shifts were perfect, the trans temp was surprisingly cool, no higher than 160, and on the way back over the bridge with the messed up way high shifts points, temp stayed at 180. Whereas the same uphill climb yesterday with the early shifts resulted in 200-217 temps.

[DmaxMaverick]

Mashing the pedal on the uphill climb reset the TV cable to where it MUST be. Independent and regardless of everything else, if it is not adjusted properly, you will cook the tranny in a hurry. If the cable moves freely, it's in good shape. If it slacks while releasing the throttle, it may need cleaning (don't use WD40), or replacing.

[AugustDiesel]

Mashing the pedal on the uphill climb reset the TV cable to where it MUST be. Independent and regardless of everything else, if it is not adjusted properly, you will cook the tranny in a hurry. If the cable moves freely, it's in good shape. If it slacks while releasing the throttle, it may need cleaning (don't use WD40), or replacing.



Thanks dmax. I tried retracting first then smashing the pedal, but there was no discernible difference in adjustment, the black sleeve over the cable was still fully retracted. I'll try it again thus afternoon, perhaps I didn't smash the pedal hard enough during adjustment.

[AugustDiesel]

I also noticed that the black sleeve appears to be cracked at the tip. Is this made this way or does this indicate cable damage and have an affect on my shifting patterns?


3626

[DmaxMaverick]

It doesn't look cracked. The end is a cap with a hole in it for the cable. They are normally loose fitting. Pull the cable. If it snaps back quickly, it's OK. If it retracts slowly or snags, it needs attention.

In regards to your temperature observations, 700R4's live and die according to heat. The vast majority of heat generation is related to the converter, and it's simple. If you run it under load while unlocked, it gets hot. Keep it locked and it doesn't. However, TC lock events don't effect shift points.

[AugustDiesel]

It doesn't look cracked. The end is a cap with a hole in it for the cable. They are normally loose fitting. Pull the cable. If it snaps back quickly, it's OK. If it retracts slowly or snags, it needs attention.

In regards to your temperature observations, 700R4's live and die according to heat. The vast majority of heat generation is related to the converter, and it's simple. If you run it under load while unlocked, it gets hot. Keep it locked and it doesn't. However, TC lock events don't effect shift points.

According to my builder I DO have the 1200 stall converter, but I can't really tell when it's locked or unlocked.

Do I need to disconnect the cable from the throttle body before testing or just pull on it while it's disconnected?

[Robyn]

Get the TV cable adjusted properly.

Press the "button" on the cable bracket where it snaps into the rear of the clip at the rear of the manifold.

Shove the adjustment all the way towards the firewall.

Mash the throttle to the mat.

The cable is now set properly.

With the throttle open fully the TV CABLE should be just snug (Valve fully activated)

If the VB in the tranny came from a gasser rig there are other parts in it that are calibrated differently than in the diesel.

Shift valve springs are different.

Did you install a shift kit ???

I recommend a Transgo -2 (Dash 2)

For most heavy service on the 700R the more aggressive settings in the kit are a good way to go

[AugustDiesel]

Get the TV cable adjusted properly.

Press the "button" on the cable bracket where it snaps into the rear of the clip at the rear of the manifold.

Shove the adjustment all the way towards the firewall.

Mash the throttle to the mat.

The cable is now set properly.

With the throttle open fully the TV CABLE should be just snug (Valve fully activated)

If the VB in the tranny came from a gasser rig there are other parts in it that are calibrated differently than in the diesel.

Shift valve springs are different.

Did you install a shift kit ???

I recommend a Transgo -2 (Dash 2)

For most heavy service on the 700R the more aggressive settings in the kit are a good way to go


My builder used the same valve body from my old trans since it was still in good condition. I haven't installed a shift kit but will look into it. I'll adjust the tv cable as prescribed this afternoon and report back on findings. Thanks!

[AugustDiesel]

If the VB in the tranny came from a gasser rig there are other parts in it that are calibrated differently than in the diesel.

Shift valve springs are different.

Did you install a shift kit ???

I recommend a Transgo -2 (Dash 2)

For most heavy service on the 700R the more aggressive settings in the kit are a good way to go

After saying what I did about the valve body from the old trans, I also remembered that I have no idea if the old trans was original to the truck or not.

The closest thing I'm finding to the "transgo -2" kit that you recommended, Robyn, is the "700-2&3" valve body rebuild kit. Is this the same thing you're talking about?

[AugustDiesel]

Okay, so I adjusted the tv cable a prescribed by both Robyn and Dmax: I push down on the D shaped button, while holding down the D shaped button, I push the adjustment sleeve all the way back, with the sleeve all the way back, I get into the cab and push the throttle pedal as hard and as far as I can to the floor. No change in cable adjustment.

Cable setting prior to smashing the pedal:
3627

Cable setting after smashing the pedal:
3628

I take it for a short drive, no change in shift points. 1-2 is still really high at 25-26 mph. I pull over to adjust the cable back some, I push down on the D shaped button, and the adjustment sleeve automatically pops out to this setting:

3629

So I drive it, still no change in shift points. 1-2 still at 26mph. 2-3 and 3-4 follow suit at very high shift points.

Sometimes, if I pop off the pedal, I can get it to upshift at a lower speed, but not always.

Before doing any of this today, I did test the tv cable by pulling on it and it sprang right back without any hesitation.

At this point. I don't know what to do.

[Robyn]

Hmmmm

I see no real difference in the before and after pics ???

Are you sure on the calibration of the governor you put in ???

The diesel governors have heavier weights compared to the gasser ones.

Also the springs are different too.

At really light throttle the 1-2 shift should be under 20 mph.

Another test you can do to check the TV setting is to do a light throttle upshift and as soon as it shifts MASH it and it should drop to 1 again.

If no down shift then there is not enough TV pressure. (Cable set too loose)

The entire package is calibrated for the diesel.

This is the governor and springs
The individual shift valves and springs

Plus other components in the VB.

Mixing and matching can cause things to get real hinky.

The 700 2 &3 kit is the one.

3 IIRC is a manual shift conversion.

The 2 comes with a new spacer plate, springs, a valve or two and some drills to enlarge some holes.

[AugustDiesel]

I'm sure y'all are tired of me by now, but, I at least think I've made some progress. Tried pulling the tv adjustment sleeve all the way out to see if that made a difference in shifting, it did. Shifted super early rather than super late. Then I had the thought, that if the gas pedal has no effect on the tv adjustment as it should, perhaps there's an issue with the throttle linkage to the gas pedal. Then I thought, what if I set the tv cable all the way back to the firewall, then pull back all the way on the throttle linkage arm (instead of the pedal) and see if that makes a difference, and it did! The TV sleeve popped back out just a little bit, which brought the 1-2 shift down to 20mph. So I adjusted the TV sleeve out a little more, and that finally brought the 1-2 shift back to 15mph, 2-3 at 25mph, and 3-4 at 50mph. Down shifts seem to be okay too, didn't try out 4-3 down shift, didn't want to push my luck. At this point I'm thinking I may have the same situation Convert2diesel had. Just glad it's shifting like it should now. Throughout the testing, temps stayed below 180.

[AugustDiesel]

Hmmmm

I see no real difference in the before and after pics ???

Are you sure on the calibration of the governor you put in ???

The diesel governors have heavier weights compared to the gasser ones.

Also the springs are different too.

At really light throttle the 1-2 shift should be under 20 mph.

Another test you can do to check the TV setting is to do a light throttle upshift and as soon as it shifts MASH it and it should drop to 1 again.

If no down shift then there is not enough TV pressure. (Cable set too loose)

The entire package is calibrated for the diesel.

This is the governor and springs
The individual shift valves and springs

Plus other components in the VB.

Mixing and matching can cause things to get real hinky.

The 700 2 &3 kit is the one.

3 IIRC is a manual shift conversion.

The 2 comes with a new spacer plate, springs, a valve or two and some drills to enlarge some holes.

So the diesel governor I ordered was the same one you sent me the eBay link to. Installed it right out of the box. The valve body is the same vb from my old trans, but I have no idea if that trans is original to the truck or not. I wouldn't be surprised if it wasn't, as there is really nothing in the truck that's original at this point (PO tinkering, probably a bad purchase on my part in retrospect).

I can tell you the new 700r4 was not built specifically for diesel application, so it's possible there is more in there that's not calibrated right (although, all of the upgrades are recommended for diesel 700r4s as well).

I'm certain the 2-3 kit is in my new future. Does it require a professional to install or can I do it myself?

[Robyn]

Get a pressure gauge on a long hi pressure hose and connect it to the main line and see wassup during operation.

LEFT SIDE OF TRANNY ABOVE SHIFT SHAFT A BIT


Here are some numbers out of the GM book

Tranny warm

1000 RPM



Range Minimum Maximum
Park 90-110 190-230
Reverse 95-120 200-300
Neutral 90-110 190-230
Overdrive 90-110 190-230
Drive 90-110 190-230
Second 185-230 185-230
Low 185-230


Manually move the TV cable to get the min/max positions.

If the numbers are good then the issue is elsewhere in the box as far as shift points.

TV IS SOOOOOOO CRITICAL ON THESE.

Do the pressure test static and then do it running down the road to see how it does.

[AugustDiesel]

Get a pressure gauge on a long hi pressure hose and connect it to the main line and see wassup during operation.

LEFT SIDE OF TRANNY ABOVE SHIFT SHAFT A BIT


Here are some numbers out of the GM book

Tranny warm

1000 RPM



Range Minimum Maximum
Park 90-110 190-230
Reverse 95-120 200-300
Neutral 90-110 190-230
Overdrive 90-110 190-230
Drive 90-110 190-230
Second 185-230 185-230
Low 185-230


Manually move the TV cable to get the min/max positions.

If the numbers are good then the issue is elsewhere in the box as far as shift points.

TV IS SOOOOOOO CRITICAL ON THESE.

Do the pressure test static and then do it running down the road to see how it does.

Got a pressure gauge kit coming tomorrow.

Got the 700-2&3 kit coming Monday. I plan on dropping the pan next week anyways to make sure nothing is damaged so I figure that's the best time to install it. Hopefully it's not too complicated ;):D

[AugustDiesel]

Of course, I do have another question: at the column, as I shift between park, reverse, neutral, overdrive, drive, second, and low, once I get past overdrive and move towards low gear, the shifts st the column feel less and less firm to the point that I'm not even sure if I'm in low gear. How do I go about fixing this?

[AugustDiesel]

So I just finished watching the installation video for this shift kit, and man is it tedious/overwhelming. Question, part of the install includes modifying the servo, but I already have a corvette servo in the trans, so couldn't I just skip that part?

[DmaxMaverick]

Contact TransGo. There may or may not be an advantage.