justin8798

hey yall ,
im new here so i have a 1998 xj sport 4x4 and im having a pain wid the tranny , ive replaced all selonilds x2 pcm and the tcm x3 and tps , it starts out in 3rd gear @2300 rpm , it dont up shift or down shift automatic only manual . iv checked all the wiring to and from pcm , tcm and tranny and all the fuses . and its still codes out po758 and po700 . its my dd so please help.

sik_xj

have you checked the tps? I had a buddys cherokee that the tps went out on on the trail and it wouldnt shift at all. and swapped a good one in and fixed everything. Other than that I had a cavalier that one of the selenoids went out in and it was buried in the trans and it was easier to swap the trans then replace it...you may just need a new trans..

And I am not quite sure what you are saying....you have an auto trans, and it will only shift when you shift manually by putting into 1 and then 2 and so forth?

justin8798

yes sir if i manually shift it goes all thru all the gears but if i put it in OD it will only shift 3rd and OD

sik_xj

I'd test out and try to swap out your tps. I would just see what happens, Id say that you are probably would be better off swapping in a new trans though

justin8798

damn im lost stuck at a stand still replace the tps again and still zip any ideas

Radi

Do you have a solid ground connection to the trans case? The Manual says the trans grounds through the harness. It doesn't. At least not well enough to operate the solenoids. There needs to be a solid ground path or they won't operate correctly.

Also verify that you are getting 12V at the solenoid connectors when shifting. Run a couple test lines from the trans harness into the cab and connect a DVM. Don't count on probing the TCU output to tell the truth. Check @ the trans itself.

bajaxj

Have you adjusted the tv cable? Its the one that goes from the throttle body to the trans.

justin8798

@radi i do have 12v 2 them when shifting but im not sure about the transfer case tho but ima do that in the am, @bajaxi ive done and and saw it at the pump thanks yall

Radi

By "trans" case I mean the transmission, not the transfer case. Sorry for not being clear.

Those solenoids pull a fair amount of power and the little tiny ground wire in the transmission harness is marginal at best when it's new...and degrades over time like the rest of your grounds. The solenoids need a good ground to operate, they normally find one through the chassis. If not, they can show +12V but not operate with enough force to do their job.

justin8798

@ radi i didnt mean transfer case but i knew what you was saying