I got this 88 xt6 full time 4x4 with auto trans, it just doesn't shift . here is what I know :

Tested all the solinoids inside and they all had the proper OHMS.

Tried another (known good ) computer.

Road test, in D it starts off in 2nd, will shift to 3rd, and that is all it will do .

It will do the same thing with shifter in 3

If you put the shifter in 2, the whole thing sort of locks and will not go at all

1st hold button seems to have no effect

It will back up in reverse.

If any of you are transmission wise please help me out to diagnose this ,

its a EAT 4 spd. with full time AWD Thanks !

change the fluid and filter/screen (i dont know if the 4EAT's have those tho) and get some LSD additive (the liquid kind for LSD diffs) and pour it in there along with the new ATF. Give that a spin.

Check this site out, they may have an answer for you.

I have the same tranny, but havent had the car long enough to know all the problems with it.

XT6.net

Does the speedometer work?

 

Any leaks or fluid loss?

 

Gaining fluid in the front differential?

what if the speedometer doesn't work, Shawn? I have pretty much the same symptoms (not all the time though (??)) and my speedo doesn't work

Well ,yes the fluid is fresh and no the diff and trans are not on a transfusion program, the speedometer does work , and the filter screen is not restricting fluid flow. I did have one other bit of info, the shifter cable was damaged from a front ujoint failure and it may have jerked the inhibitor switch that is mounted to the shift lever on the trans, (I did reset it )but if the switch was damaged and gave the trans computer bad information can this part cause these symptoms ? I'm hoping that a knowlegable trans guy will see this and help out. Thanks again !

Does the speedometer work?

 

Any leaks or fluid loss?

 

Gaining fluid in the front differential?

sounds like it's not going into the correct gear. does the gear light on the dash read the correct shifter position? there's no front u joint so i'm guessing it was the front axle or am i missing something? have you checked all the circuits to the inhibitor switch? seems like if that thing was compromised at one point, it or it's associated wiring could be damaged as well. have another one to swap out? there are plastic parts on the inhibitor which are not the most resilient pieces after 15 years of operation. i think this switch is an excellent place to start.

 

are there any actual shifting problem to indicate internal issues?

 

the FSM has tons of information for stall speed and line pressure testing if you have the patience to do that.