Transmission help

[bd blk 12v]

Hello guys. I have some questions on a 96 ram 2500 4x4 auto I purchased. I have searched and need more help. The truck will not shift into od. I have a snap on mt2500 scanner. I have checked for codes no trans codes. I tried the functional tests on the relays under the hood the dash od off on switch. Those all work and function. I then tried the solonids in the trans for od and lockup. I crawled under and listened at the pan they were clicking. When you drive the truck it shifts 123 but no od. If you leave the od switch on it seems in 3rd to feel lockup rpms drop nearly maybe 50 or so. The trans temp reads 2.7v and 8128 degrees celcius. Could the temp sensor be at fault. Driving with the scanner hooked it shows 4th gear but it isn't. The truck has 3.55 gears and at 65mph is 2500 rpm. Thanks for the help I'm lost.

 

[95cummins5.9]

I would think you answered your own question in your post. 8128° C ???? Start there.

 

[bd blk 12v]

I hooked up a gauge in od and have 4psi. If I let off the throttle it jumps to 8psi. It doesn't slip or act like neutral. If I turn the od switch off it goes instantly to 0.

 

[LAmiller]

You probably have a cut seal on the overdrive piston.

 

[bd blk 12v]

Does the trans have a fale safe with the temp?