200k OG 4l60E slipping....opinions please.

[swharris]

206k on original trans. Fluid changed every 30k, flushed every 60k from new. Trans cooler since 30k, one long tow trip about 100k ago. Never any issues until recently. It sort of slips while in high gear(high speed). You can feel a slight surging as it slips and then catches. It stops if you let up a bit. Only does it under light throttle. Upon hard acceleration there is no slipping. Shifts fine(auto or manual) up or down. Fluid is clear, fresh and full.

Is this a sign of an eminent death? Start saving for a rebuild? I'd like to stretch this thing for as long as possible. Would a thicker additive be of any help? Is this a torque converter issue? No access to a lift currently, so not looking forward to pulling it on my back...ugg. Thanks for any input!

[rev_les]

it's possible that it's the lockup clutch in the converter starting to slip. Under heavy throttle the tcc unlocks,under light throttle it engages. 206K out of the original transmission is pretty decent, I'd start saving just to be safe.

[swharris]

That is exactly what it seems like it is doing. Would an additive help? If I pull for the converter, is it silly not to do the entire rebuild?

[rev_les]

I'm not a transmission expert by any means, but as understand the converter clutch has paper clutches, so if it's already slipping I'm not sure a viscosity improver would help,and might just cause more problems with the trans itself. As for rebuilding it, if at all possible I'd have the trans rebuilt while it was out anyway. If you have it rebuilt, make sure they put in a new sunshell. The r&r really isn't too bad if you have some tall jack stands and a big floor jack on a concrete driveway. ( or better yet, a lift) I pulled mine in about an hour and a half under my carport a couple of months back .If you go that route, make sure to read up on the various threads on here for helpful info unless you've done this a few times!

[swharris]

Thanks for the information! As crazy as it seems, the problem turned out to be a bad cap and rotor! For some reason originally the missing (the surgging I was feeling) would only appear under light load. No missing at idle or in neutral<shrug>. As time wore on, the missing started happening all the time and I could feel it in idle and neutral. Needless to say, I'm very happy it was only the cap and rotor. She's now running better than ever....with the exception of the clunking U-joints. It never ends huh? Thanks again!!

[rev_les]

beats the heck out of a trans repair