Thread: 4T65E converter slips in/out on highway?

trannyman..help me here, as well as others.

this really only happens at highway speeds, but i will be cruising along (lets say ~70) and my converter will unlock all on its own and then lock up again a little later.

what is this a symptom of? converter going out? lockup solenoid bad? it has been bothering me for quite a while..

oh no!

...faster? haha, just kidding.

if mine goes im just going to put another stock non-hd tranny in it again. this one lasted this long, so why wouldnt it last just as long with another?

Does it feel like a constant oscillation or does it lock then fall out of lockup for a few seconds altogether and then lock back up? The pcm controls lockup as well as the apply rate and also monitors torque converter clutch slippage. If you have a scan tool or have access to one you need to watch commanded TCC duty% and TCC slippage when this is going on to verify what is or isnt happening. Without scanning there is really no way to know what the pcm is seeing to work with.

it completely falls out of it and comes back in after a short amount of time. it does do the jerking when im pushing it into boost when the converter is locked, but i usually let off and ease back into it so i dont have to do that. i havent ever scanned while it was happening, good idea. ill look into that and check back.

the problem with race transmissions is that they use race parts, which usually should be rebuilt every so often. i do not ever want to touch the transmission. i dont even change my fluid, just add more if its leaking.

What race transmissions are you talking about? What race parts? Not sure where you heard any of this from but there really is nothing like that in the Grand Prix market. Thats why I dont call mine race transmissions as it is easy to confuse what RACE really means, and from a race-car standpoint you would be correct but what is out there is just not that way for these cars.

i was under the impression that the upgraded clutch packs wore a lot faster, but i could be wrong. although im sure a high stall doesnt help much either.

either way it is more cost effective to me to just keep replacing it with another stock one. they are cheap.

I dont know of anyone that uses race frictions and the only company that makes them for the 4T65E is Raybestos and they are the Blue plates. Raybestos clearly states NOT to use these in a daily driven street car as they require replacement roughly every 5-10K miles but again I have never seen any trans build buy the other guys that had these clutches. Other than that there is nothing special other than upgraded hardparts to prevent breakage and failures from occuring with higher powered cars.

what hard parts would you normally put in someones tranny who drives their car fairly hard on the street everyday? i dont like to do 3-1 downshifts because of how harsh they are on everything. i dont really go to the track or run slicks either, so that's part of the reason why i dont have many problems with my transmission.

Once you get to the 13.0 range or in that ballpark the input shaft becomes a potential weak link and also the stock V6 chain sets stretch and can break really any time going WOT once the mileage gets high on them. I would go with an upgraded input shaft and I also use V8 chain sets in all of my performance rebuilds that still use the stock dual chain setup and they work very well. Other than that on the 97-02 cars the 4th clutch shaft also needs to be replaced with a hardened one to prevent losing 4th gear.

hm..ill have to give you a talkin to when my tranny starts to actually go out. for now im just going to sit on it and baby it.