Failing 7AT , Torque Coverter or Other?
 

90k miles on 2010 with only CAI and axleback exhaust.

Trans. Fluid fully changed at 72k and didn't exhibit any signs of burning etc. Dumped again at 82k and it still looked, smelled new. Has a cooler since 80k miles.

When attempting some tuning pulls in manual mode 3rd gear at 2k rpm it twice instantly surged to 3k before settling back down to 2k and taking off. Almost like it I was put in neutral and back in gear. This happened twice within 10 minutes of doing 4 pulls, two pulls it didn't happen.

Other than that the transmission has behaved normally, no codes, no AT light.
Does this sound like symptoms of a torque converter issue or other in your experiences?

Thanks for any insight you can lend. :tiphat:

That does sound like a Torque Converter lockup clutch slipping. If you can tell if it is in lockup mode when it does it, that is a dead giveaway.

The only way to tell if it's in lockup mode is to come to a stop and see if the car wants to keep moving stalls correct?

Will power braking to check the stall speed help with any diagnosis?


I've been watching countless video's etc. but haven't found any that demonstrate the issue I'm having. My tuner said the log looks like a definite decoupling of the transmission from the engine.

Thanks for your assistance.

The decoupling does sound like a TC lockup problem but could be something inside the transmission itself. There may be a troubleshooting procedure in the FSM (link in sig).

10-4 I'll get a look.

Been driving, shifting etc. fine the past couple of weeks. Only happened the two times listed above.