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98 Auto trans expected miles before failure?

bvillebud

NAXJA Forum User
Location
Berryville
My 98 DD has about 125K on the clock. It has been my experience that the “average” automatic transmission has a lifecycle to between 150K and 175K miles; what is the story on the XJ auto transmissions? Any suggestions on a good source for a replacement when that time comes?

FWIW I change my synthetic oil every 5K and drain the tranny fluid, so I’m hoping for a few extra miles from the trans; we’ll see.

Thanks!
 
my 93 hass 199k and ive had ni issues with the trans and my 95 has 194k also no issues with the transitself, but i did manage to break the driveplate on the 95 due to lots of abuse and a couple missing bellhousing bolts
 
My first AW4 outlasted the engine it was attached to, which died at 211k miles. I replaced it with one that had almost exactly 200k on it, it still works to this day. My 4.0 and AW4 now have over 225k miles on them, and both are functioning rather well.

I must take this opportunity to state that my XJ's odometer now reads over 236k miles, meaning that if a suitable road existed, it could by now be on the surface of the moon. Of course I would have needed 790 gas stations, an engine, and 3 alternators along the way.
 
It would all depend on how it was used (Normal Driving, Racing, OffRoad, Etc.) and what Temperature the fluid was at while it was being used.

I use a 40,000 GVW External Trans Cooler. I do not use the Radiator Cooler. I live in Florida.

If one Lives or Travels in/to Colder Areas then one might Invest in a Fluid Control Thermostat Kit which allows fluid to bypass a cooler until 180° F. Shortens warm up time in cold weather.

Here a Chart for Transmission Temps:

heatchrt.jpg
 
Thanks, you are right, I have thought about adding a cooler. Where might one find the temp control unit? I'm googling & looking at Jegs now, but recomendations would be appreciated.
 
I guess I should add, my 225k AW4 has had a cooler installed for the last 25k miles. As far as how it was used:
Normal driving - check
Racing - check
Offroad - check
Frequent burnouts - check
and it has gone several miles, several times at 110 mph, and has frequently been spun at 5000 RPM.
 
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mine finally clunked out at 198k. a little early from what ive seen but this poor tranny looks like it had the original fluid and filter in it. so not bad in my book.
 
If you're not towing and using synthetic fluid, you don't need a cooler. If you are just draining fluid though, you are getting way less than half of it. Disconnecting a cooler line to run old fluid into a bottle and refilling (like a quart at a time, run and stop, refill, run and stop, etc.) until you get clean fluid will replace almost all of the old. Drain and refill the pan first. If you search the threads, you can find detailed discussion of this method.
 
My old XJ had 260K on the clock and the trans still shifted awesome. One of my buddies had an AW4 quit on him (towing without a cooler and then a horrable attempt of fixing it in replacing the torque converter). He swapped the tranny from his old Jeep and it now has about 290K and he drives his 3K every month. Still shifts good too.
 
The AW4 is pretty robust. The vast majority of tranny problems in the XJ as easy to fix electrical problems like a bad throttle position sensor or a bad shift solenoid in the tranny. Keep it cool and use the right fluid (not ATF4+ since its not a Chrysler made tranny) and you're good to go.

Speaking of TPS sensors. I cleaned up my oily engine bay with simple green and a hose a few weeks ago. Got in it yesterday for the first drive since then and it wasn't shifting right. Giving it more gas made it upshift, so I knew the problem right away - I killed the TPS sensor. Took about 10 minutes to swap in a spare one from the parts pile. Just when I thought I was being careful and didn't use the pressure washer...
 
The AW4 is pretty robust. The vast majority of tranny problems in the XJ as easy to fix electrical problems like a bad throttle position sensor or a bad shift solenoid in the tranny. Keep it cool and use the right fluid (not ATF4+ since its not a Chrysler made tranny) and you're good to go.
that, and keep an eye on the tranny fluid cooler lines, they like to come loose. and no AT can last long running dry.
 
Sitting on 212K on mine with weather from upstate new york or texas and florida and still runs like a champ. burnouts and offroad trips are still keeping it going.
 
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