5R55E Reverse shudder when hot

[Gregc99XLS]

Hi, I'm totally new to Explorers and this transmission so bare with me. I've read a lot about the reverse issues that seem to plague these units. I got the vehicle cheap since the reverse was acting up. It has 131,000 miles. Otherwise its in good shape, doesn't seem to have been abused etc. I was told it would pretty much loose reverse when it warmed up. So I dug in and installed a Sonnax Zip kit, all new solenoids, new reverse servo, VB gaskets etc. I'm pretty sure I got the VB lined up right. Now when I was in there I basically did not find one problem I could see. Which had me a little worried since I like to know what the issue is for certain. No blown gaskets or O-rings or any metal or sludge in the pan. Now after replacing all these components it drives great in forward, seems to shift fine. Reverse works great when cold but starts shuddering and not wanting to move after the vehicle is well warmed up. It will be worse at some points like when climbing a small grade. I noticed after one of these fits it seemed to stumble a little when I left it idle after reversing. The idle seemed higher and did not go down right away. Could there be a computer issue that's affecting it while in reverse? Like I said all new solenoids so shouldn't be any problem there. Check engine light is on also so I assume there is a code but I haven't tried to read it yet. I hope its just that and not rebuild time! Also the reverse servo piston pin was starting to crack and the end was mushroomed just slightly. I wonder if the band has an indentation in it also that's making extra slack. Don't know if this would be any issue though since reverse is good when cold.

 

[jd4242]

You adjust you bands?? Get that code and do a master reset?

 

[Gregc99XLS]

No I didn't adjust the bands yet. It doesn't have an adjustment for reverse, just intermediate and front band according to the ATSG manual. Would it help if I adjusted them? I think I have a code reader around here, I'll see if I can get them.

 

[Gregc99XLS]

Alright, my actron pocket scan says no codes. I'll try it again soon, hoping something shows up. Reverse goes in strong when cold. I'm not sure if I have 1st gear though. My shift indicator is off so I need to get that fixed also. But I tried putting it in 1st and just revved with some slight resistance but no movement. I haven't replaced the two servo's n the side yet. Wondering if they could be losing pressure.

 

[JK080]

I wouldn't worry about the servos on the side, they dont have anything to do with reverse or 1st gear.

You may want to check the line pressure, reverse requires more line pressure to work.

Did you replace the EPC solenoid as well?

 

[Gregc99XLS]

I'll see about getting a gauge to check it then. Seems like its getting plenty of pressure cold. Yes I did replace the EPC too, new Borg Warner part.

 

[Gregc99XLS]

Update: Reverse seems to be working good now after putting some miles on it. Think I have the shifter adjusted now. Still have no 1st, it just revs with a slight resistance like it wants to go but held back. Valve body gaskets not lined up? Anyone have the part number for the bonded VB gasket and where to get it? All the other gears seem to be fine.

And still codes or lights flashing, check engine light is off.