We have just noticed that we have 80W90 in the TJ 231. I know it is supposed to be ATF, but will the 80W90 do it any harm? Can I switch over to ATF with out problem? :confused:

yeah 80w90 is too thick. it'll probly overheat and/or gum stuff up and then you'll break the 231.

i'd recommend draining it, cleaning it out with solvent (brake cleaner maybe? NOT WATER!!!;)) and filling it with ATF. or could go the expensive way, get 5 gallons of ATF, take it to a shop, and have them pump it through the case until you're almost absolutely sure it's clean.

Like WillyPete said, you may burn it up. The mechanical pump inside is made of plastic and cannot pump the thicker fluid as well if at all. You may burn up the bearings as well as melt the pump and other plastic components inside the 231. Flush that sucker!

If it were mine, I'd just put ATF in and run it for a short time, and then change it again.

I'd drive it in 4hi and low to make sure all the piece parts move around and get cleaned out.

AFT has alot of detergent in it should clean out any residual gear oil in there.

I'd get the gear oil out of there ASAP and not even worry about getting it warm, just get ATF in there and it should clean things up. Do the second change with the oil warm so any trapped gear oil will flow out easier.

- Dan

Originally posted by Dan-H
If it were mine, I'd just put ATF in and run it for a short time, and then change it again.

I'd drive it in 4hi and low to make sure all the piece parts move around and get cleaned out.

AFT has alot of detergent in it should clean out any residual gear oil in there.

I'd get the gear oil out of there ASAP and not even worry about getting it warm, just get ATF in there and it should clean things up. Do the second change with the oil warm so any trapped gear oil will flow out easier.

- Dan

Thats what I would do! It's not a very expensive service to do either, they only hold 2 1/4 qts. Good luck.

False alarm, I'm not as dumb as I though I looked.
I cracked the drain, and it's blood was red.


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