46RE no reverse after changing front band!

[1bad55chevy]

Quick run down! Purchased a 2003 Dakota R/t 5.9L regular cab 160k miles as a parts truck for my shop ($2200) and it is in AMAZING condition. The vehicle would not go into park and would not kick down and upshift properly so I figured the front band was shot. I removed the pan and VB to swap the band and to my surprise was in perfect shape! The anchor had fallen off preventing it to engage and from going into park. While the VB was off I decided to go ahead and swap out the band and adjust both since I was already there and put the unit back together. I backed the vehicle off the lift and out of the shop and took it for a test drive then it hit the fan! coming out of the parking lot it seemed to have a drag inside the tranny that quickly went away and was shifting PERFECTLY going down the road so I returned it to the shop and parked it out front. a few hours later I go to move the vehicle and now it has no reverse! I put the truck back up on the lift and drop the pan to find that now the rear band is TOTALLY fried!! I also noticed on my scanner the 3 4 shift actuator was showing engaged in all ranges including park (this turned out to be a broken spring in the VB).

To ALL the 46RE experts out there what would have caused that rear band to apply when it was in drive and how do I prevent this from happening again?? I am going to drop the tranny this weekend to replace the band and also the VB since I have already found 1 broken spring in it.

I know its not a Ram truck but it is a Dodge and it shares the same tranny! Also there seems to be a lot of knowledge here so I figured I would ask!

 

[Fast69Mopar]

Reverse is achieved by simultaneously engaging the L/R band(low/reverse), and the -HI-drum. So with no reverse one of those is bad.

The other reason for why the L/R band is engaged in a forward gear is when the shift lever is in manual low.

Is the truck trying to creep forward while the shift lever is in neutral?

 

[1bad55chevy]

No the vehicle idles in neutral just fine and does not creep.

This is what makes this super strange!

I took the VB apart trying to understand it and got lost after a few minutes. I wonder if something got stuck in the VB which caused that passage to stay open while it was in drive.

Would the governor solenoid have anything to do with this??

 

[1bad55chevy]

Looking at pictures and trying to think back on how it went together I might have screwed this up....

If I would have screwed up putting the VB back on and put the Accumulator piston in upside down would that have caused the issue??

 

[Fast69Mopar]

Looking at pictures and trying to think back on how it went together I might have screwed this up....

If I would have screwed up putting the VB back on and put the Accumulator piston in upside down would that have caused the issue??

It's very possible that if you have the accumulator piston upside down it will cause a problem. The seals on the piston are lip seals that hold fluid pressure one way and bleed pressure the other.