xjtje90f30

Hi all,

Not sure if anyone can help.. 90 jeep xj AW4 4.0 drives great in drive and 1-2 and 3… but whenever I put it in reverse it engages, but won’t reverse except for the normal load, when I hit the gas it doesn’t go any faster just revs up like in neutral. I lifted rear end and put it in reverse and the wheels spin, and when I hit throttle they spin faster. Not sure what’s going on, any ideas? I checked tranny fluid and even replaced the tranny fluid and filter. I uploaded a few photos of my tranny with pan off maybe someone will see something I don’t. Reverse works when I lift off ground and hit gas etc but when on pavement won’t go lol… so confused any help would be appreciated… trying to get this fixed ASAP got a trip to camp on beach in a few weeks.

cruiser54

Have you ever adjusted your throttle valve cable?

xjtje90f30

Never, any good reference on how to adjust, under the hood I noticed it was a little loose, atleast I thought it was I’ve never messed with throttle cable so I wasn’t sure if I was right
or not, could this be the issue? How tight/loose should it be? I did replace my TPS a few weeks back and that’s when I noticed.

cruiser54

xjtje90f30

Mr. Cruiser as always, you are right. Adjusted that bad boy and REVERSE it back in full motion. Thank you so much sir. At end of month I will donate to your website sir, you have now helped me 3 different times.

cruiser54

I love happy endings!!! Way to stick with it.

xjtje90f30

alright, so I thought it was fixed until I drove it today. Went to reverse now it definitely reversed more and faster than before but it’s still struggling to move quicker in reverse I really got to mash the gas sort of. I re-adjusted the throttle valve cable again but nothing. I attached a video of what attaches to TVC not sure if it’s suppose to be like this. Any other suggestions? It almost feels like when I hit gas to reverse the rear tires are struggling to turn against the ground? Seems like it locking up so to say?

here is a video of throttle valve cable.


and here is a video of me trying to reverse it’ll go but I got to mash the gas.

cruiser54

Try this. Disconnect the TV cable from the throttle body. Pull the throttle valve cable out as far as it goes. Clamp it with some vise grips. Re-do your test.

xjtje90f30

Im assuming you mean like this? If so… HOLY moly what a difference in both DRIVE and reverse… now how do I permanently fix this? My Xj gets up and goes now both in drive and reverse I’ve never seen it like this. So much more responsive when I hit the throttle… in both drive and reverse… will I n need to replace this cable? Or what could be the permanent fix? Because this XJ is my daily, and I am not sure if I can drive it normally like this with the vise grip? or should I put it back to how it was until I can permanently fix it.

cruiser54

You crack me up!!

I'm not a transmission person. But, this makes you wonder about a stretched cable or a screwed up whatever it is in the trans that the cable pulls.
You don't have a crimped metal cooling line do you?

FWIW, I'd rather drive it with the trans pressure high than low and slipping.

xjtje90f30

I can check metal cooling line tomorrow… in terms of driving it should be safe to drive with the vise grip holding it for a day or so until I can replace that cable… obviously I know you can’t guarantee but for the most part safe for like 1 day I can try to replace the line on Thursday, if I can find a cable somewhere.

I just found a bunch of stuff on stretched/
TV cable, hopefully I can do this in my garage at home. Ty cruiser if you thinking of any thing else let me know I trust your judgment. But I’ll tell you right now that jeeps responsiveness went from being a calm old buck to a hyper young buck from what you told me to do with the tv cable and vise grips.

xjtje90f30

so haven’t driven the XJ much since it’s been nice out been riding the motorcycle. But I thought this was a temporary fix… thought it worked in the moment but… since trying this with the TV cable pulled with the vise grips… it somewhat works in reverse, but my 1st gear is sluggish. Really works hard to get going. Reverse works some what. So put TV cable how it was normally and reverse acts like neutral don’t even feel it engage. I do feel it engage when I pull the TV cable. Any suggestions?

cruiser54

You have low transmission line pressure for some reason.
This Jeep have an auxilary trans cooler by chance?

xjtje90f30

nope just the factory setup. Any suggestions on how to troubleshoot low pressure? Do You think my TPS output voltage would affect this? I was going to check/adjust it tomorrow morning, via your tip and make sure it’s at 83%. I did have to replace the tps a few weeks back when the old one got wet and died on me, got it from advance auto parts.

Or possibly a TCM/TCU ISSUE? Ever heard of reverse issues being related to tcm/tcu failure? Or a bad ground by dipstick tube?

Or maybe one of my lines is cracked/leaking?

Or should I replace TV cable? So many damn things not sure where to start…

really don’t want to have to rebuild.

cruiser54

You could always unplug the TCU and see if anything changes. Try R and 1-2 and see if there's any improvement.
Line pressure can be checked with the proper tools/gauges.