Delayed Reverse Band Engagement

[William Wallace]

Hello everyone, I've recently had a problem with my 4r55e out of my 95 Explorer 4x4. I rebuilt it in December, put it back in, and everything worked fine. A few weeks ago, I noticed a whine noise when i shifted into reverse. It would last a few seconds, and then reverse would engage and work alright. Well the other night, I put it in reverse and it made the noise again. I gave it some gas, and the noise got louder with increasing RPM. I didn't move the whole time this was happening. I didn't touch the VB during the rebuild, so I'm wondering if that is my problem. It sounds like the reverse piston isn't getting enough fluid pressure behind it, which isn't engaging the band all the way, which is letting the drum rotate in the band when it isnt supposed to. Any suggestions?

Note: This isn't the distinct "reverse whine" made by the cut of the gears while the vehicle is moving. Thanks for any input

 

[Glacier991]

Do you get manual first?

 

[William Wallace]

yes sir, all forward gears work fine.

 

[BrooklynBay]

Welcome to this forum! The low/reverse servo piston controls low gear as well as reverse, so I would suggest that you rebuild the valve body at this point. A shift kit might be a good idea. I would recommend the "D" style viton ring kit for the low/reverse servo. It's a tighter fit than the stock O rings. Did you use new valve body gaskets, and an In/Lb torque wrench on the valve body bolts?

 

[coliniscool]

Hey Glacier, talk to me man!!! Do you still have that t-case?? (BW4405)

 

[BrooklynBay]

Glacier991 has a BW4405 from Quasarsky which he is going to use in a new diary.