Low Reverse Pressure
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1st Gear
Joined: Jan 2026
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Low Reverse Pressure
Need help. Got a 99 4R100 with PTO and had to do complete rebuild. Also installed Transgo Tugger Reprogramming kit. I have all forward gears. Reverse will engage once RPM’s rise then will move. If under load or slight uphill in reverse will feel like slipping and starts to puke fluid out the top vent. The pressure readings I get all forward gears within spec, reverse only reads 30 psi. I did air checks along the way during rebuild. I have since dropped the pan and performed another air check. Low reverse piston moves and do not hear major air leak. No other abnormal air leaks from rest. Coast clutch seems to have a slight hiss but again all forward gears pull no problems. Drove it about 60 miles and no problems with any shuddering, slipping, delayed shifts moving forward. Truck moves in reverse after having to give good amount of gas. If anyone has any advice to which direction I should head next, would be greatly appreciated.
