700R4 towing

[Supercharged111]

I suspect the powertrain control improved in 96 and later years; perhaps other "improvements" were made then too, to mitigate whatever problem(s) this sticker was intended to address.

Just a guess.

My '98 K1500 Sub doesn't have that door sticker.

Did the TBI trucks have torque management at the end? Of course that only counts on the shifts. I suspect steady state torque application dictated that sticker in the door jamb.

 

[1998_K1500_Sub]

Did the TBI trucks have torque management at the end? Of course that only counts on the shifts. I suspect steady state torque application dictated that sticker in the door jamb.

My casual observation / belief is that '96 and later had improved TCC control, e.g., to mitigate temperature rise of the ATF, particularly under conditions where cruise control was engaged in hilly or similar, variable-load conditions.

 

[Supercharged111]

My casual observation / belief is that '96 and later had improved TCC control, e.g., to mitigate temperature rise of the ATF, particularly under conditions where cruise control was engaged in hilly or similar, variable-load conditions.

That only pertains to the application of the TCC though. I guess we can only speculate as to GM's perceived weakness of the thing 95 vs 96.

 

[Schurkey]

The '88s have torque management for TCC operation, and I'm pretty-sure for shifting.

 

[89gmc]

It absolutely was the transmissions fault. Considering my 97 belonged to my parents to start with and neither of them had a lead foot. The first 4L60E destroyed itself on a 1-2 shift taking off at moderate throttle with my mom driving the thing. The 4L65E blew up on a 4-2 downshift getting on the highway while I was driving it after I owned it. Had shorty headers and a mild cam making about 350 hp at the crank. 4L60E derived garbage should have never gone into the vans as GM themselves even lacked the trust to put a 4L60E behind a 4.3L 8-lug and used the 4.3/4L80E in many of them. 4L60E definitely should not have come with a 3.42 gear behind it in a van with the L31. Loads of stress on that POS transmission just getting the thing rolling from a stop. The Astro/Safari vans with the 4L60E also had a habit of nuking the 4L60Es at low mileage. I put a couple dozen 4L60Es in the M vans when they were newer and they all had under 100K on them. The 4L60E is like an undersized fuse in the driveline.n a power

Thanks for the info. I thought that the 406e's were better than the 700r4's. I have got a couple of those that I am going to attempt to go through. I have done quite a few YouTube videos so far and as I have been a power plant mechanic for 30 years I might be able to do this.

 

[89gmc]

It has been close to 20 years ago now, but when I was in my Automatic trans class at the trade school I attended we built 4L60Es. There were like 20 of us in the class and we built like 5 units in groups of 4. If I remember correctly the problem is actually more low line pressure causing lack of cooler flow. If the bushings, lip seals, etc are worn and have fluid leak, the converter charge and thus cooler flow are limited. A 700r4 and 4L60E do not have much in the way of excess pump flow especially at lower rpm. When we had them hooked up to gauges on the transmission dyno the the cooler line pressure was extremely low even on units that had been gone through while they were at low rpm. When you shifted it from say Park to Drive the cooler line pressure was non existent during the shifts. One of the units had Zero cooler line preasure and low line pressure. Subsequent tear down on that unit found that a teflon sealing ring had been pinched during assembly. It still shifted through the gears but would not apply lockup and would have failed in a short time in a vehicle. That team had to go back through that transmission, find and correct the issue before they had a passing grade for that transmission build.

Similarly the AOD that I had a hand in building would not shift. On the dyno we noticed it did not have any governor pressure to the governor pressure tap. We removed the tail housing, swapped the governor and then it shifted fine. When we pulled the old governor apart it had rusted stuck valving inside. Sticking governors were a problem on the old AODs.

A very good instructor is https://www.transmissionbench.com/. The guy is very through and does things very logical and slow so you can learn. I have picked up a ton watching him . Some specialists advise not replacing the turbine teflon shaft seals at all because I suppose the chance of tearing one.

 

[Scooterwrench]

All automatic trannys slip and burn clutches during the shift when towing. To prevent this I shift with my right foot. Stab the pedal,back off,let it shift then stab the pedal to run up through the next gear.
You are creating two issues when towing in OD. The pump isn't spinning fast enough to create good line pressure to hold the clutches and your lugging the engine and it's oil pump is not spinning fast enough to create good flow. I use the 500lb rule when towing or hauling a load. If it weighs more than 500lbs then OD is out of the question. I've never burned up a tranny right foot shifting and using the 500lb rule. Hopefully I didn't just jinx myself!

 

[Supercharged111]

All automatic trannys slip and burn clutches during the shift when towing. To prevent this I shift with my right foot. Stab the pedal,back off,let it shift then stab the pedal to run up through the next gear.
You are creating two issues when towing in OD. The pump isn't spinning fast enough to create good line pressure to hold the clutches and your lugging the engine and it's oil pump is not spinning fast enough to create good flow. I use the 500lb rule when towing or hauling a load. If it weighs more than 500lbs then OD is out of the question. I've never burned up a tranny right foot shifting and using the 500lb rule. Hopefully I didn't just jinx myself!

I think the owner's manual gives you something in the 3000# range. I've always heard if it isn't hunting for a gear it's OK to tow in OD with the 4L60. But then again I don't tow with one anymore.

 

[GrimsterGMC]

I always let the TCC determine when I should drive in 3rd, if it keeps disengaging then 3rd it is, if it will stay engaged in OD then that's good too. It's when the TCC disengages that the trans temps start to climb rather quickly and that is what you are trying to avoid. Every road and load is different so drive according to your journey.

 

[HotWheelsBurban]

I always let the TCC determine when I should drive in 3rd, if it keeps disengaging then 3rd it is, if it will stay engaged in OD then that's good too. It's when the TCC disengages that the trans temps start to climb rather quickly and that is what you are trying to avoid. Every road and load is different so drive according to your journey.

Yup, towing on flat ground is way different than in the hills or lots of grades. When I towed with my Burb, as soon as we got to the hills out from Houston a bit, it went into D instead of OD. Now I have my one ton crew cab with a 4L80 so towing can be done in OD and get a little bit better mileage. 11 when towing and that's moving 9500# at 60mph.