hey everyone,
so ive got a 98 expedition eddie bauer 4x4 with the 4r100 transmission...ive lost all ability to shift into gear. at first it only would go into first...but felt very difficult to move and then would shift hard into 2nd if i let off the gas and got back on it.
then all of a sudden it lost everything...even park. i was shifting through neutral to first and it made a big bang and then all of a sudden the truck drove perfectly again. went to park it backwards and then after i stopped, it lost all gears again.

what's odd is that everything worked perfectly then nothing. its almost as if the trans doesnt know where im shifting it. i ordered a new MLPS (manual lever position sensor) for it.

would anybody have an idea on what it could be? i know a lot of these transmissions have odd electrical issues and valve body issues with springs sticking and breaking. also the OD light is NOT blinking and there are no codes being thrown.

sorry for the wall of text! any help or insight is appreciated!

 

How many miles? If I had to guess I would say TQ issue? Hows the fluid level and the fluid itself?

 

Its got 189k. Fluid is still pinkish red and at normal level....tested it warm with the truck on. Doesn't smell burnt either

 

I dont know why but just from me looking around it seems the expys have more issues with there 4r100 than the trucks? Wonder if there is anything different in the 2 but I dont see why there would be. Im sure someone will chime in

 

It isn't the MLPS or anything else electrical. It is a mechanical problem. It could be a problem with the shift cable or something inside the transmission. It could be the transfer case, too.

 

That's what I figured since it didn't throw any codes.... The previous owner used it a lot to drive to lake Tahoe so its seen quite a bit of snow. The mlps looks pretty nasty so I figured replacing it wouldn't hurt.
I did forget to mention that when trying to shift into park it makes a loud gear grinding sound. I have to shift to neutral then shut off the engine to get to park....but even then it doesn't hold the truck. I have chocked the wheels.

Maybe the transfer case is stuck between modes?

 

Mark, thank you for suggesting the transfer case. I shifted to neutral and was switching to modes and it clunked into 4low pretty hard. I now have park and it will shift to first and second. Looks like the transfer case is stuck in 4 low.

 

Mentioning that would have helped. That bit of information confirms to me that the problem is in the transfer case, not the transmission.