dying aw4

[ratrapp]

i think my 186k mile aw4 is dying.in the morning it shifts perfect.when it warms up it progressivley takes longer and longer to shift each gear until it quits shifting.it doesn't slip and always goes in gear,just doesn't want to shift.i tried a fluid to change but it didn't help(didn't figure it would but i tried anyway).after you let it cool off it 'll shift again for while.you can't manuallly shift it when it does this anf both tcu fuses are good and i even swapped the tcu out for another but it does the same thing.i don't want to try a used tranny as most in our local yards have as many miles as mine.any suggestions as where to get a new one?i checked at team cherokee and they have ones for the 91 up xj for 1425 plus shipping.

[Motion Offroad]

Have you changed out the filter?

 

The AW4 uses solenoids to change the gears. Does it do it in every gear change or just a specific one (for instance 1st to 2nd)?

[ratrapp]

i tried a filter and it does it in every gear.it starts in overdrive first and works its way down to drive and then second.i let it sit a few hours and it starts shifting again when it cools down.

[JeffN]

maybe your cooler lines are clogged somehow and keeping the radiator from cooling the fluid off

[deziped]

There are 3 solenoids in the AW4. Check OMH's on them, they should be in 11 - 15 ohm range to be good. Any less or more than that they are probally bad. However it is unusual for all three t0 go out at the same time. You can check them by unpluging the TCU and with the key OFF use a circuit tester. Ground tester in slot D7. Insert positive end in C 14 (Converter Clutch Solenoid), C 15 (Shift Sol 2 which is 3rd gear), and C 16 (Shift Sol 1 which is 1st & 2nd gear). Jusst another step you use in searching for problems.

[sinkrun]

Old rubber line collapsing after it gets hot???

[ratrapp]

i unplugged my tcu and i can manually shift it fine.i'm going to check the ohms on my solenoids today after work.at least i know my tranny itself is good which is a big relief.still seems funny when it's cold it'll shift fine until it warms up but i'm checking the solenoids today.

[ratrapp]

checked ohms today.shift solenoids 1 &2 are both 18 ohms and the converter clutch solenoid is 33 ohms,ouch.i haven't felt the converter lock up in years and that may be why.may also contribute to 15 mpg on the highway.anyway i ordered a complete set of solenoids new from tranmissionpartsusa for $158 shipped.i checked mopar and the 1 and 2 solenoids were $135 apiece and the converter lock solenoid was $240 so i went another route.i'll manually shift it until they come in.it worked fine today manually shifting it.thanks for the help so far.

[ratrapp]

i replaced all 3 solenoids and they read the same as the old solenoids.it still doesn't shift unless i unplug the tcu and manually shift it.i'm now wondering if the used tcu i tried is good and i may try to find another used one.i think it only fits up to 90 as i i found another used one out of a 91 and it wouldn't plug up.

[mnkyboy]

I knew a guy that was having a similair issue turned out to be a bad ground.

 

Also have you checked the TPS? I've seen it cause shifting issues

[ratrapp]

i got my scanner from the shop and it only shows .37 volts at the tps and it only moves to .39.i think the less than 1 year old tps from mopar is going bad.they sais something about not warrantying it when i bought it because of it being considered a vintage part.i wish i could adapt a new ho tps to the renix wiring because i've already got a ho throttle body.

[ratrapp]

i replaced the tps and it registers correct voltage and idles good again but still no shift.i'm wondering if my new shift solenoids are any good or the used tcu i tried was any good.before it wouldn't come out of first unless i unplugged the tcu(which i think was from the bad tps.i unplugged the tcu so i could manually shift it.i replaced the solenoids and i plugged up the tcu and it wouldn't move unless i put it in 1-2 gear.it never did this until i relaced the solenoids.i wish i had checked tps voltage first but i didn't.i'm going to stick the old solenoids back in wednesday and try again.

[ratrapp]

problem solved.the tps was the original culprit.i replaced the 3 solenoids first and one of the new ones was defective.i put the old ones back in and all is fine.