Transmission Issues

I have been having intermittent problems with my transmission. In city traffic after the car gets hot my transmission will start upshifting hard. It only happens in the city and it doesn't happen but a couple of times a week if that. I took it to a shop and they said I have two transmission codes-

PO 742- TCC CKT stuck on
PI 811- Max adapt and long shift

They wanted to pull the transmission take it all apart and charge me $500 to see what was wrong. I wanted to get your guy's take on this before I took this plunge. Thanks for any help anyone can give.

Usually these codes are caused by the solenoids in the trans which when scanned can be checked before disassembly. Only the side cover comes off to change the pak, also a worn valve body for the TCC can be another issue, a line pressure test may be in order also, prior to any work, but none of the preliminary diagnostics cost 500.00, if they cannot or will not do the afore mentioned diagnostics, get it to another shop.

When was the last time the tranny fluid and filter was changed?

It's probably been a long time. I bought the car at 110,000, and its just under 140,000 now. I'm hoping to get the filter and fluid changed Mon.

You tranny pan is full of silt at 100k+ and you need to get the sludge (silt) off the pan when you change the filter. The gasket is reuseable and a replacement is hard to find (Napa).

Do a search for "Sea Foam" on this (Intrigue) forum for tranny cleaners and tranny solenoid lubes. Taking a tranny off to replace anything is expensive and throwing a rebuild in almost makes more sense = that is costly, but just changing the tranny fluid a few times to try to get it clean again is worth the try.

Manually shift from 3rd to OD (4th) probably makes more sense for you.

I agree with maxwedge..... I know dealers can sometimes be expensive, but sometimes a dealer with a good transmission guy can often know the problem by hearing your complaint, or by reading the codes.

your problem most likely a EPC (electronic pressure control) solenoid. Faulty on all the 4t65e's....requires quite a bit of labour to drop the trans a bit to gain access to the side cover. Most reputable trans shops with experience will recommend at least a partial overhaul, as its likely the 4th gear overdrive hub has gone or is about to. Basically theres not a whole lot of ways of saving money, unless you go the route I did and ignore the problem. My car would slip/shudder when hot uner hard take-off.....so i would take off easy. Eventually the p1811 max adapt/long shift would show up basically saying theres too much slippage in the transmission so it goes into maximum line pressure to keep the trans from slipping, causing hard shifts. Some say an additive called 'seafoam' run through the trans for a few weeks can improve the problem, but its only a shot in the dark.

Same thing just happened to me the I had both of the same codes and the Transmission has be be rebuilt. Depending on your amount of wear and tear the hard upshifting caused. Mine caused alot within the 10 miles I started noticing the hard upshifts. I just had the shift selunoids replaced about 3 months ago and everything was fine up until this past sunday. figures 5 days after the warranty expired. They said the valve body is shot the gears are worn and the selunoids blew again. So the total damage is about 2k for parts and labor. They could have just replaced some select parts for 800.00 dollars but my cars history isnt all that great since I got it used so I just told them to get it all done at once to prevent another costly future trip. The car only has 89k miles on it.