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AW4 shifting early!

Y

yamahjeep105

NAXJA Forum User
Location
california
Hey guys as the title says my 98 xj 4x4 with an aw4 trans all of a sudden started shifting very early, now ive researched for a couple weeks now and im finally crying out for help.

heres the setup 98 xj 4x4 3" rustys lift on 31s. i replaced the shift solinoids with the upgraded ones to fix my non down shifting problem when i first got the jeep about a year ago, i do have a constant P0700 and P0740 CEL which is torque converter lock up (had it since i bought the jeep). i have tested the lock up at 60+ mph by lightly pressing the brake and i see the rpms jump then it locks back up. was working great!!

but my problem now is that when it shifts into 2nd,3rd the rpms drop waay down to about 1000 at just light throttle its never done this before.
and at 60+ the TC dosnt unlock like it did before... please help its my daily

ive already
adjusted the TV cable 100 times
changed the fluid
tried anouther TPS
no changes thanks alot guys, im thinking i may need a new TC??
 
Brake switch needs to be adjusted or replaced.
 
Is there a separate tc switch off the brake pedal like the older ones? Do you have a scanner to watch the input/ output speed of the trans?
 
Hmm brake switch? I'll try it.. But my lights work fine. Would that cause it to really shift early? All I have is a cheap obd2 reader not a scanner so I won't be able to do that one
 
On the early xj with the aw4 there is a separate switch just for the TC. On my 89 it is the white switch above the brake light/ cruise control cancel. Im not too familiar with the newer xj but its something to look into to cover bases.
 
I'm definitely going to check that out tomorrow, it does feel like the TC is just constantly locked, when I cone to a stop it almost dies then it comes out of gear or whatever
 
It might not solve all your problems. But it sounds like your problem with dieing when you come to a stop or why the tc won't unlock when tapping the brake. The brake switch tell the tcu to unlock the tc. Check all your connectors for corrosion also. It can be frustrating as all hell but just diag one thing at a time and you'll fine the problem.
 
Okay I adjusted the brake switch and nothing changed, if I give it 1/2 throttle or more it will down shift and take off but idk once its cruising steady the rpms just feel too low.. And when I'm coming to a stop it will get to about 400-500 rpms just as I'm stopping then it comes out of gear like normal.. But going down the hwy at 60mph I'm right around 1000rpms just for reference.. Thanks guys!!
I've checked cleaned and dielectric greased most of the connections under the hood. I'm missing something its getting frustrating, could it be a bad TC?? Or bad transmission?
 
What axle gearing do you have? I doubt its the trans its self, the aw4 nearly bomb proof. I had a atf/ coolant mixture in mine with 200k+ miles, cleaned it up and its fine to this day. BTW what type fluid have you been putting in it? It uses dex/mercIII. NOT ATF+4
 
Yeah if I drive until it shifts to second then floor it it will down shift and pull to redline and shift normal, as far as gearing I cant remember off the top of my head I know it has the factory LSD though. I'm running napa Dex merc not atf+4. And it came out a little dark and didn't effect the shifting. And it got a new trans at 160k from the previous owner I have the receipts for it. I doubt its the transmission also but dang idk what else it could be. I'm about ready to put a new TC in it but I'll be pissed if that isn't it after all the work lol
 
Haha I'm on top of this lol I tried changing the tps with zero change so I swapped back. I haven't check the trans fuse is it in the fuse box under the hood? As far as codes I haven't driving it enough for them to come back. But every time I clear them it takes a couple drives for them to pop back up
 
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