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Allisonforeman, Transmission foreman
Category: Heavy Equipment
Satisfied Customers: 300
Experience:  Factory trained by Allison Transmission on all on Hwy products including the Hybrid Electric drive,
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& reverse..1000 rpm shifts normal all speeds pulls no slipping

Resolved Question:

allison mt643rm low pressure 1st & reverse builds pressure after 1000 rpm shifts normal all speeds pulls no slipping over the road
Submitted: 6 years ago.
Category: Heavy Equipment
Expert:  Allisonforeman replied 6 years ago.
Hello and thanks for using Just Answer,my name is XXXXX XXXXX I would like to help you with your question. The fluid level being high does point to a pump problem not enough fluid is being scavenged from the sump, Hence the low pressure at idle. Check the simple things like a missing O ring on the in pan sump filter pick up tube, But other than that scenario low main pressure equals pulling the transmission and repairing the cause, worn pump,bad seal on low reverse piston, ETC.

I hope this information helps, Happy new Year!
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