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AW4 slippage while sitting on steep inclines while wheeling

indirocz28

NAXJA Forum User
Location
tx
Have a 1999 XJ, I haven’t wheeled with it too much. It’s on 35s and long arms with 4.56 gears. About as “built” as you can be for a “stock” rig.

While wheeling this weekend, we noticed on these steep incline rock ledges that if you don’t make the obstacle within the first one or two attempts the transmission seems to starts slipping in all gears, and reverse.

It will still move, but definitely requires quite a bit more RPM.
Once you’ve made it back to flat ground, and let it sit for maybe a minute or so, it operates properly again. I’ve checked the trans fluid in neutral at operating temps multiple times, and it is all good.

There is also an external trans cooler installed.

The last rig I had was LS powered with a TH400, and it never had any type of slipping like this if I had to sit on an obstacle for a while.


Trans works great in all other scenarios. Well, I can’t say for sure while going down, because those usually go quicker, but it never seemed to care.

Where should I be looking?

Has anyone ever installed an accumulator for reserve trans fluid?
 
Are you using the specified Dexron-III/Mercon ? Some XJ Cherokee owners report AW-4 slippage and weird shifting when using alternative ATF types.
 
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