[b]Launch shudder with the 4T65E transmission[/b]
[b]Launch shudder with the 4T65E transmission[/b]
(OP)
I have a 4T65E transmission in my 2000 Chevy Venture Extended Van with about 100K miles. Recently it has developed a shudder, at moderate or aggressive launch from Stop light. The shudder happens between 5 and 15 mph (so no TCC related issue?). Any pointers to root causes...?





RE: [b]Launch shudder with the 4T65E transmission[/b]
RE: [b]Launch shudder with the 4T65E transmission[/b]
RE: [b]Launch shudder with the 4T65E transmission[/b]
RE: [b]Launch shudder with the 4T65E transmission[/b]
When the oil is burnt or contaminated, that will be shortly before the end of the life of the transmission. I suspect there is a better margin on parts than there is on new cars.
Regards
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RE: [b]Launch shudder with the 4T65E transmission[/b]
"I totally believe in lifetime fill for oil in ATs."
I do not believe in that at all. The fluid breaks down. I have been through many trans and the ones that i went through most of them never had a trans service. The customer could not show a history and checking vehicle records. I am a firm believer that companies are only going to lifetime on trans fluid to sell the vehicle but the trans will fail eventually (between 80,000 and 130,000). I have seen trannys finally take a dump on abused vehicles in between 200,000 and 300,000 miles and even higher with a service at around every 50,000. But we all have our own opinions, just going off experience.
RE: [b]Launch shudder with the 4T65E transmission[/b]
My inference was that the life of the transmission would be the life of the oil, not the other way round.
An early breakdown of the oil will result in a transmission failure.
Regards
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RE: [b]Launch shudder with the 4T65E transmission[/b]
RE: [b]Launch shudder with the 4T65E transmission[/b]
In addition to mentioned trans issues, seized or badly worn cardan type u-joints can cause interesting low speed shuddering reacting against softly mounted center support bearings. My RWD Volvos often need a u-joint or 4 every 100 kmiles or so.
RE: [b]Launch shudder with the 4T65E transmission[/b]
A lot of folks are skeptical about 'fill-for-life' fluid claims, but such a thing is technically practical for 200K or more lifetimes in passenger vehicles. In a previous job I evaluated the condition of factory fill ATFs from consumer vehicls MY ca. 1996-2000, having service (all in Texas so high T but no hills) of 85-135Kmi, one each of light truck/SUV and automobile each from Chrysler, FOMOCO and GM. I compared that to similar data collected 5-6 years before. Observations were:
1) Of all the vehicles, only the 135Kmi one showed measureably degraded friction properties- though no driveability concerns- and it had experienced a fluid leak early on in it's life (would've been disqualified from the test if this was known before it was sampled, but it was reportedly serviced with factory fluid).
2) The RWD vehicle's fluids appeared marginally better than the FWD, suggesting lower severity despite possibly heavier duty cycle (towing/hauling).
3) The previous study showed generally poorer fluid durability despite the sample cohort having on average 10K fewer miles.
It was clear from the data that ATFs in routine service could last in excess of 100K, and that the performance had been improved in the factory fill fluid from the early- to the late 90's (and has presumably gone up in later specs). If the fluid's properties haven't changed but the parts are shot then it's they that aren't as 'durable' as the lubricant.
RE: [b]Launch shudder with the 4T65E transmission[/b]
DRWEBB, You must not have read the begining, tcc wont engage at 5-15 miles an hour. That not correct at all. 4t65s don't have that many tcc issues as does the 96,97 and some 98 4L60e. 4t65es though do have pressure control solenoid issues. I put my money on the solenoid from the description above. Gm CV axles are pretty solid. If it was a mount you should get more of a clunk, POWER brake it and give it a little gas and shift back and forth from reverse to 4 and watch and listen for abnormal clunk noises (thats for mount diagnosis). Probably a pcs issue though.
Peace!!
RE: [b]Launch shudder with the 4T65E transmission[/b]
Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling
RE: [b]Launch shudder with the 4T65E transmission[/b]
TCC shudder could happen if the friction material was warped or chunking off, it would be happening all the time and causing a feeling of actuation. Though the description is slipping applied friction elements, if not due to an internal leakage, then due to low control pressure, or now worn out clutch packs. Are all shifts normal? Check the simple things Vac modulator (throttle valve control) even such things as TPS and VSS that regulate control pressures.
RE: [b]Launch shudder with the 4T65E transmission[/b]
RE: [b]Launch shudder with the 4T65E transmission[/b]
I know that the latest engine oils have dramatically reduced levels of zinc for emissions reasons, but I don't know about ATF. Zinc is good for sliding friction - I have heard that hot rodders are wiping out new solid lifter cams using these new oils and the recommendation is to use diesel oil (usually Rotella) instead.
ISZ
RE: [b]Launch shudder with the 4T65E transmission[/b]
I'll defer to the parts and software experts on this diagnosis. But despite my point on durability- generally speaking a fluid service as a first countermeasure for many tranny problems is a comparatively cheap & easy way to ensure one component of the system is in factory spec.
RE: [b]Launch shudder with the 4T65E transmission[/b]
this was directed to the ones who think it is the tcc, if you lock a torque converter at a low speed it like letting your clutch out on a stick going 10 in forth gear.
this vehicle has nothing vaccuum to the tranny.
RE: [b]Launch shudder with the 4T65E transmission[/b]
RE: [b]Launch shudder with the 4T65E transmission[/b]
It is, to be honest, rather a small device, and if you keep abusing it, it will fry.
Cheers
Greg Locock
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