Trouble with built Allison 5 speed slamming into reverse

Klamb17

New member
Jan 20, 2022
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When my transmission gets to operating temp it has a 2-3 sec delay before it engages into reverse then jerks/grabs really hard making an awful clunk etc if the truck is cold it shifts normal and smooth. All other gears etc shift just fine as they should. absolutely no codes so I was wandering if I’m looking at a leaking seal or if it would be something simpler like in the valve body. Tia