Allison 5sp: 3-4 shift not right

[hallmansauto]

ok just ran truck on rack with tires off ground when computer commands 4th it doesn't go it stays in third unless I bring rpms up but as soon as iget off throttle kicks down to 3rd so guess tranny coming back out will post what I find

 

[IOWA LLY]

Why are you doing this on the lift? You need to take it for a drive.

Sent from my SM-N920V using Tapatalk

 

[paint94979]

Why are you doing this on the lift? You need to take it for a drive.

Sent from my SM-N920V using Tapatalk

x2

 

[Bonestock]

Did you start with a friction or steel in your stack?

 

[WVRigrat05]

Why would you check it on a rack? That's zero comparison to driving it down the road under a load.

 

[hallmansauto]

ok removed trans found that I didn't install Torrington bearing on end of main shaft and c1 drum had to replace reinstalled didn't fix problem so I removed valve body installed a used on shifts great so anyone tell me what I did to valve body fell like an idot for missing bearing but s--t happens

 

[hallmansauto]

found problem in valve body check ball from transgo kit that goes in trim valve fell out during install remember that trim solenoid falling out will I was trying to hold it in and get retainer installed maybe this will help someone else