LMM: Lockup problem in 5th

[lutzjk913]

Posting this for a friend

2010 LMM with marks tuning and a 65mm Danville charger

He has a LMM And just got the transmission built. Has a Georend R Converter in it. He is experiencing a issue in 5th gear with around 25% throttle so basically normal driving. This will only happen when tow haul is not engaged. It acted fine for 500-600 miles after being built before the issue began.

Once he reaches 52-55 mph and is in 5th gear the truck acts like the converter locks up then immediately unlocks and then it proceeds to lock up for good.

We took my TCM off of my LMM and it worked fine. We drove it for around 30 mins with no issues. Bought a new TCM today and had it flashed with stock TCM tuning. The truck ran fine for about 40-45 mins and it does it about 30% of the time now where before with his old TCM it did every time.

Any insight gents?

 

[Mike L.]

What does the builder say? We have no way of knowng after someone worked on it.

 

[aatemple]

Mike, I’m the one that’s having the issue.

The transmission builder initially said it was the tcm. Like joe said we threw one in and it worked so i bought a new one and it worked for a little and now it’s back to doing the same thing just not as often. I have not called the builder back to let him know it’s doing it again. I plan on doing it tomorrow.

I was just curious if anyone has ever ran across this problem before.

Excuse my ignorance and correct me if I’m wrong, but my hunch is that there is a problem inside the transmission and with the new tcm, after time may be seeing the problem and trying to correct it with its adaptive learning causing this weird lock-unlock-lock in 5th under light throttle.

 

[Mike L.]

You aren't giving us much info. How much power are you running. What did the Tech2 say as far as command, slip speed?. Could be problem with the converter flow valve, or sealing ring on the stator shaft. Was there a CEL? If so, what was the code#? Too many variables after someone hacking into to it.

 

[aatemple]

Made 600/1100 at Danville Monday. Haven’t put a scanner on it yet. There is no CEL. Just talked to the builder and he seemed pretty stumped. Told me to bring it in so he can hook a scanner up to it and go for a drive to see what’s going on. Seems to be temperature related, lockup is fine until the trans temp reaches 160, once it’s at that temp it does it every time.

 

[lutzjk913]

Wanted to update this

Truck is going back to the shop next week.