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2008 Black TBSS
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3,532 Posts
Discussion Starter #1
Trans is a FLT Level 5 and works completely normal except I have to let off the gas to shift from 1st to 2nd. No codes. I don't normally diagnose by replacing parts. However: the common trans symptoms thread says:

1-2 shift does not happen at WOT until you let off the gas: Best case: try replacing the TPS. Middle case: leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator). Doublecheck by using the pressure gauge and watch for a big drop when the PCM commands 2nd gear. Worst case: poor line pressure rise (see below).

Talked to Chuck at FLT and he said it wouldn't be the 1-2 accumulator because the level 5 has a billet part. Replacing TPS is not a major task , otherwise I need to drop the trans and get it to FLT. I'm leaning towards replacing the TPS as the first step in diagnosis as it's only a $30 part. Any thoughts?
 

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TT AWD TBSS Jeep
TT AWD SS Pwrd Jeep
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5,825 Posts
Since the ECM requires both parameters to be set (RPM & MPH) have you tried lowering both quite a bit in the tune to see if that fixes it. Verify the ECM is seeing the MPH right as well, just in case speed sensor is acting goofy at WOT.
 
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