4L60E Issues

[roadrunner_70]

'93 C1500 2WD, 115K. Transmission was fine. Had oil changed a month ago. Noticed fluid was high(overfilled) on dipstick, but wasn't til transmission started leaking from filler tube, and U joint, that problems developed. When cold, won't engage Rev or Forward. Must rev up to about 2,000RPM. Slips in and out of gear til warmed up. Fluid level is now close to normal, with no burnt smell. Could this be the result of overfilling? Or is this a classic failure of a)pump, or b)torque converter, or c)internal leakage. Any advice appreciated.

[maxwedge]

Originally Posted by roadrunner_70

'93 C1500 2WD, 115K. Transmission was fine. Had oil changed a month ago. Noticed fluid was high(overfilled) on dipstick, but wasn't til transmission started leaking from filler tube, and U joint, that problems developed. When cold, won't engage Rev or Forward. Must rev up to about 2,000RPM. Slips in and out of gear til warmed up. Fluid level is now close to normal, with no burnt smell. Could this be the result of overfilling? Or is this a classic failure of a)pump, or b)torque converter, or c)internal leakage. Any advice appreciated.

Overfill will not cause this unless after driving for a while it foamed up then there may be an issue.

[Blue Bowtie]

What oil was used to refill the trans?

[roadrunner_70]

Dexron III was used, I believe. The tranny is in pieces now at the shop. The tech showed me the parts, and nothing was out of the ordinary as far as wear. His best guess is hardened seals that caused a pressure reduction. I had a list of things I gained from this forum, and mentioned a few to him. One was a common weakness in the 4L60E which is the Sun Shell. Mine wasn't that worn, but was beginning to show signs of wear, and given their failure rate I asked for the "Beast" to replace it.TCC control valve bore wasn't bad. Corvette Servo, High Energy clutches, shift kit and all electronics I'm passing on, since it's a V6 and not used for towing or heavy hauling. He agreed on another addition which was the .500 boost valve with the pump rebuild. Master overhaul kit, and sealing rings on the stator. Also a rebuild torque converter. The main solenoid is being replaced too. Is the TCC regulator w/sleeve a must at this point? He mentioned something about PWM(Pulse Width Modulation) and another type of tranny which escapes me, but this is more an issue with one than the other, and mine is the other. Okay, after all that the boss wasn't in and I have to wait til Monday for an estimate. Any guesses? The remove and reinstall alone is $400. My guess is $1200 minimum.

[troy1]

93 did not PWM the TCC so the valve hardly ever wears

[corning_d3]

I'd have the valve-body looked over as well. A worn spoolvalve or bore would give a slip until it warmed up. This is a common problem on it's front wheel drive cousin, the 4T60-E. Also, the upgraded servo, clutches, and shift kit are only gonna make the rebuilt transmission stronger AND longer lasting..

[95silverado]

I just had mine rebuilt in my 95 extended cab with all the upgrades. It was
a little over $1400. The truck has 194,600 mile on it.

[roadrunner_70]

$1900 for rebuild with upgrades. "The Beast" Sun shell, .500 boost valve, rebuilt torque converter, TCC clutch valve. That is steep, but should be solid with the upgrades. 1 Year 12,000 mile warranty. The standard rebuild for this tranny would run about $1600. They blew a brake line testing the truck, and only after I told them I couldn't drive it like that did they agree to get it fixed. I had the fluid changed on this transmission only about a month before it started acting up. Not a flush, but a change, with filter. Might be a coincidence, but I believe that the new fluid in the system might have played a role. Perhaps detergents washing away what crud had built up, but was nonetheless keeping things working. It would appear that seals had deteriorated internally. I'm sure that the overfilling at service didn't help either. If I have any advice for someone in my shoes, it would be to price a rebuild before allowing any shop to dismantle your transmission. They are reluctant to do so, always insisting that it might not need it, but once it's in pieces, what are you gonna do. Even after dismantling, they couldn't tell me what the malfunction was with any certainty. I found a lot of shops would do it for less, and with all the right upgrades.

[corning_d3]

Who'd you have do it?

[roadrunner_70]

Work was done by a local transmission shop. It's a franchise operation. Not AAMCO or Mister Transmission.

[corning_d3]

WHEW!! Well, congrats and hopefully you'll get a long service life out of it..