I'm a new 99 xj owner and am installing an SYE, so I had to drain the TC fluid. The fluid that came out was black and seemed fairly light weight oil. I'm not sure of the exact type of oil that was in there, so I'm not sure what to put back in. I don't think ATF would be good because it would mix with whatever oil did not drain out?

Does it matter if I put a different oil in that what I drained out?

Thanks

 

The owner's manual says to use Dexron III Mercon, the same as
what goes in the automatic transmission. It takes about a liter.
The little bit of what was in there won't affect anything.

If you really want it to be cleaner, run it a few days and change
the oil again.

Take care to not over-tighten the plugs, especially the drain, or
you could end up with a little leak. Napa sells a convenient replacement
plug (Balkamp BK 7041048 19mm wrench 22mm threads) that works well.

 

might be good to do tranny now too. when i got my 2000 i did all juices and did tranny 3 times in three months,done for a while, good and clean.
mine was black too...

 

Anything with a chain uses atf and anything gear driven uses gear oil.