Allison 5sp: Trans pops out of gear, acts like limp, but no codes

thunder550

Active member
Apr 2, 2013
1,176
16
38
Phoenix, AZ
I've had 2 times now when under power, my trans has popped out of gear (or shift to 3rd or whatever it does before it limps), but not throw a code. It sticks in 3rd gear (I think) until I shift to neutral and back to drive, then it acts normal again. Doesn't throw a CEL.

It's a stock trans, about 180k miles. This was on my street tune (I think 80-100hp), not quite at full throttle. It's possible this may have happened on the 4-5 shift based on the speed I was going, accelerating around 70-75mph. I have limped the trans twice before with the CEL.

The symptoms seem like it's trying to go into limp mode, I just thought it was weird that I don't get the CEL and all I have to do is shift to Neutral and back to get all the gears back.
 

cwmeaux1

Member
Dec 11, 2011
303
0
16
41
Carlyss, Louisiana
If it's on the lly ,mine lb7 5spd I had did that happen and ended up goin in 2 gears at one time:( was the park/neutral switch , I drove it threw my pasture in some water and found out switch is external on 5spd