4l60e horrible flaring in 2nd gear and WOT shifts

[matty b]

Hey guys Im seriously desperate for some guidance with a really bad issue. Engine/trans is a 5.3 L33 and 4l60e 3.73 gears and 26.2" rear tire.

While cruising everything is happy for the most part and makes all of its shifts smoothly. Proble,s start while doing WOT runs, 1-2 shift is decent but slow but once in second the trans flares at about 4500 and then badly at about 5500 and wont make the shift. Ive used two different PCMs and starting from the stock tune made all necessary changes to the shift speed tables, TCC tables ect and nothing has cured it. Ive even taken a PCM from another car with close to the same setup and it still does it. I made some runs and saw that the PCM is commanding 3rd gear but it wont go.

The trans shop believes its a programming issue and it may very well be but I am chasing my tail since nothing seems to improve regardless of what changes I make. Ive started over 4 times now with stock file and went back through setting things up and nothing.

Ive tried using the trans tuning spreadsheet which has worked wonderfully for other cars but this one wont take it. I am hoping that someone can give me some help with this so at the very least I know its a mechanical issue and not a tune problem. Im not really sure what type of info may be needed but if someone can tell me Ill provide it.

Believe me I have tried everyrthing I can possibly think of (which may not be much compared to other) and I need some help now.

[69lt1bird]

post your tune and a log

[Casey]

I made some runs and saw that the PCM is commanding 3rd gear but it wont go.

3-4 clutch is a known weak link and probably the cause..

[matty b]

what in particular should I log that would be helpful? I can guess but if there are particular things I should be logging that will shed some light on it then Ill do a log asap

[matty b]

Ok figured out its a bad transmission... Clutches are slipping under load.

Beyond that is there a recommended set of PIDs to log when doing trans tuning? I ended up using my Tech2 to digure out what was going on but it happens to show 40+ pids. Are logs with that many PIDs necessary or are there tighter group of ones that help out tuning and/or diagnosing? It really threw me for a loop since I didnt know if I was doing something wrong or not. Having a known good baseline to look at vs. actual is always helpful and I just havent found much info that tells what is good or bad, especially for someone that isnt as advanced when it comes to transmissions (Im an auto electrician that can rule out electrical and/or tuning issues for the most part not a trans tech). The shop that the car went to for trans check said it was tuning and thats what messed me up.

I guess maybe for someone else doing trans tuning and needs more info than what is given in any how-to's it'd be helpful if some more knowledgable folks pop in and maybe give some info on it.

[Bluecat]

Any time you have flaring on a 60 it mechanical. Period.

[gman4dx266]

Any time you have flaring on a 60 it mechanical. Period.

Sad, but pretty true rule of thumb.

[matty b]

I posted it in another thread but the clutches died but it was because of an electromechanical issue...

Force Motor went south. Was found after going through the trans. The biggest issue was that the trans guy said that since line pressure was able to get in the 200psi area that it HAD TO BE proramming. After going through the tuning checks another guy verified it as a mechanical issue. After fixing the problem continued and I check force motor current while watching a gauge and determined the FM needed to be replaced.

Low and behold its all better.