Allison 6sp: vibrations

[ku 808]

I am have weird vibrations while accerlerateding starts off fine but once it hits 3 gear I feel weird vibrations very slight was not there befor and does not go away if I get on the throttle hard cant feel it at first but once truck is leveled off its back ive been doing alot of freeway driving started to notice it a month ago changed all trans fluid to citgo quatrasyn changed spin on filter internal filter nothing helped and she shifts hard once in a while not smooth anymore trans was built 40k miles ago not to meny heavy tows she is my daily driver

 

[Hot COCOAL]

Call mike at Inglewood

Sounds like a valve body issue, on the hard shift? Vibrations could be a myriad of possibilities

Good luck

Who built the trans???

 

[ku 808]

A guy here in Hawaii with the help of Mike on the phone.Truck stills hammers down just not the same and the vibrations is driving me crazy

 

[Jaxdad]

U joints could be the vibration.