Trans won't shift after pre warm, limp mode? Need help
 

Heres whats going on.. I can drive my car around all day with no issues.. do low speed roll launches and toy around.. but after I stop, apply the brake, then warm the tires I'll launch and it will go through the entire rpm range until it comes time to shift then it hits the limiter. It will still drive but seems like it's stuck in 2nd or 3rd gear.. I take it home, shut it off, start it back up, take it back out and it drives fine and shifts through all gears like normal. It's happened 3 times now, once at the track and 2 times in a row since I put my racestar drag wheels on. I have a yank ss4000 and tuned by frost with an 11x11 cooler. No codes are popping up to indicate any issues.. I thought I read a thread where this was happening to someone and it was a tuning issue because the pcm didn't like added slipping so it goes into a 2nd or 3rd gear limp mode. I thought they mentioned they had a code pop up though.

Seems like that may be my issue since it goes away and drives perfect and shifts great until I brake stall it and do a prewarm.. i usually drop it down in 1st and keep it there for the prewarm.. Any help is greatly appreciated.. I'd like to fix this before track time.

Ttt..still trying to figure this out..

No thoughts? Any ideas are welcome! This Trans has had a pretty fresh rebuild to add to it.. it's just strange it only acts up during a pretty warm.. I can drive it and hammer down on it all day with no issues.. shifts are nice and firm.

Sorry, I don't have any suggestions at this time.
It does sound like limp mode, which is (usually) 3rd gear.
How are you scanning for codes - what scanner are you using?

It's an old predator handheld tuner and my other scanner is an old MAC tools scanner.. would I need a different scanner for it to show or should an SES light come on the dadh? It's just so strange.. tried a prewarm again today.. happens right away, can't even spin the wheels since it's in 3rd.. drives in 3rd until I shut it off,then start it up.. shifts normally again after that.. seems to happen very easy with the Mickey Thompson radials on. Thanks for chiming in, hopefully someone will have an idea.

Edit,

Think I found an old thread that may be my issue... I did have a code up on a VSS today.. I didn't mention it earlier thinking it was due to me having my abs fuse pulled messing with my brakes and didn't want to create unneeded confusion.. the more I think about it though, it did turn on the SES for the first time with this issue.. I cleared it like a dummy thinking "ABS fuse related" lol.. see the post I copied below. You were posting in this thread also so you may remember...

""""It's been six years so I didn't remember exactly. Checked my tune and I have P0751, 752, and 756 disabled. You're correct:758 is still enabled. I also had to disable P0502 VSS low voltage, as that contributed to limp mode after burnouts at the track. I never had problems with these codes on my TCI 3000; I guess the SS3600 had just enough extra slippage to throw them."""

I probably need to get with frost and see if he disabled this code(PO502 VSS low voltage).. maybe I'm onto something though..?? Sounds like the same exact issue.

Emailed frost and he said he has never had anyone tune it out in over 5000 tunes. He thinks there is an actually issue such as excessive wear in the output shafts or bearings.. I have no clue now, being the Trans is freshly rebuilt and I'm getting zero noise out of my gears.. and everything is perfect other than when I brake stall..

Any help or input would be greatly appreciated.. I'd really like to figure this out.. I may go purposely put it in limp mode in hopes to get that code to pop back up to see what direction it leads me.. it's only come up 1 time and I cleared it without writing it down.. it was a VSS code though

Now I see your thread and you already found what I said in my PM. All I know is that it worked for me. I'd ask Frost to go ahead and do it and I bet it works for you. PITA to ship your converter back and forth, though. Having your own tuning tool is one of the best investments you can make if you're modding these cars, IMO.

Yes it's so weird to have an issue that only comes up during a pre warm.. I'm surprised there hasn't been more of this.. you would also think if you had worn output shafts or gears you would have figured that out in 7 years.. I'm sure something would have broke by now with the way we run our cars lol.. I'm going to change the VSS for shits and giggles and see what happens and check the wiring while I'm under there..

Just an update.. I was getting the po502 code, no other codes.. could not do a prewarm without going into 3rd gear limp mode.. replaced the vehicle speed sensor and so far so good.. I've done 3 prewarms on the street and the tires actually spun all 3 times and no limp mode! If it comes back I'll update again.. It's looking good considering it went into limp mode 4 times in a row before. Thanks for the feedback guys.. I hope this helps someone else in the future if they run into this