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Curtis B.
Curtis B., service manager
Category: Heavy Equipment
Satisfied Customers: 28050
Experience:  30 years exp. with diesel engines, heavy equipment and forklifts, including lp forklifts
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Allison MT653 no 5 th gear when it is hot

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allison MT653 no 5 th gear when it is hot
Is this a new problem? Does it shift fine when cold?
Customer: replied 7 years ago.
just got the truck have no history on problem. works great when it ia cold.will stay in 5th gear until you stop or down shift. It is not attemptting to shift into 5th it all when it is hot

If the engine is getting up to speed, the governor in the transmission is the accepted item to change. You said you had already checked it? These governors all look alike but have to be the correct one for the rpms of engine. Do you know if this is the original transmission.? From what I know about Allisons, I would suggest changing the governor.Thanks.

Customer: replied 7 years ago.
the numbers match the motor and the transmission as from the factory
My recommendation would be to take the assembly number off transmission and get a new governor and gasket to match from Allison.
Customer: replied 7 years ago.
Why would it only work when it is cold and not when it's hot
The governor is sticking after it gets hot. I don't like throwing parts at something, but there is no test for the governor. Got another unit with same setup where you could swap governor to test?? Sorry, wish I had better answer.
Update, I just got off the phone with the Allison representative for the Southwest. He is an old friend I worked with at the Allison dealership. He says the problem is going to be low pressure at the high clutch. Meaning the clutch seals are leaking on the high clutch. He says he doubts governor will help. It will work cold but as oil gets thinner, the seals leak to much to hold pressure. A clutch pressure check will tell the tale. Good luck.
Customer: replied 7 years ago.
thanks for the help that was where i was going in my mind. not to good with automatics have rebuilt some old car three speeds not been into Alisons. can you tell me what tools are needed to rebuild above basics
A good manual, big snap ring pliers and a small press. Not something I would recommend if you have never torn one down.Good luck.!
Curtis B. and other Heavy Equipment Specialists are ready to help you
Customer: replied 7 years ago.

Thanks for the help

Customer: replied 6 years ago.


thanks curtis for all the help. you got me on the wright trac and replaced govenor and cleaned screen. all is working good. drove many miles and is working great.

Thank you.