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Discussion Starter · #1 ·
So recently my Allison started acting weird. The 4th to 5th gear shift wont happen unless im extremely babying it or put it into N then back into D. The fuel filters only 2k old(plan on changing it and cleaning my air filter also). The spin on is roughly 6k old. The strange thing is its not going into limp mode. There is no CEL. It seems to do slightly better when warm. Trans fluid is good as far as level.

Im just trying to gather thoughts. I have a ppe kit ready to go in but I dont have the time for another month.

I plan on changing my FF first. Spin on allison second, then a full Allison flush with Transynd. Im curious what others thoughts are? Could a stuck solenoid in the valve body cause my issue?

Im prepared to build it im just curious on possible causes since its not throwing a code. Also plan on hooking the v2 up and looking for stored codes since i havent done that either.
 

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Change the fuel filter-!

Check for codes-!
 

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Discussion Starter · #5 ·
Scaned, no codes.

Drove to motor trucks for two new filters and got it to throw a CEL. P700(generic trans code) and p1721: pressure control solenoid stuck off
 

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Discussion Starter · #6 ·
From what ive read sounds like tcase, speed sensor, or tied up gears.

Im leaning towards the tied up gears...this tranny has been abused. Tcase was replaced 5k ago and no idea about spend sensor.
 

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Discussion Starter · #7 · (Edited)
Cut open the cat filter. Not dirty what so ever or clogged. Just going to have to find the time to build it between 7 day work weeks the girlfriend and the two girls running around driving me up the wall haha!

Also check frp before changing filter. Was perfect and where I wanted it...should of known to leave the filter alone lol
 
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