So I very recently purchased a Jeep XJ (1998, 5spd Manual with the I6). Only paid 1500 for it, but it was mostly a pavement pounder and is pretty clean with 150K on the clock.
Anyway - I have been systematically flushing all the fluids on it and I finally got around to the transfer case. I dropped the old fluid (which was brown and disgusting) and put in about a quart and a half of new ATF +4 (cheap walmart brand for now, synthetic in a few hundred miles).

My driveway is slightly inclined (like 3% or so), so I jacked the rear up to level it out while filling, and overfilled it a little bit (there was still fluid running out of the fill hole when I put the plug back in). Drove it around the block in 4-hi and as I was coming home the check engine light came on. Put it back in 2wd but it stayed on (even after an engine restart).

I had only used 4-hi once before, and again just went around the block but I haven't seen a CEL pop up in the 50 miles I have driven it so far. I dont have a scan-tool handy to pull the code (will order one on Amazon right now), but I was wondering what I could have messed up - if the light is even related.

Anyone seen this before? First post on CF and I already ****ed something up

 

The CEL is unrelated most likely.

BTW don't drive the jeep in 4wd on dry pavement unless you have fulltime 4wd.

 

I pretty much figure its unrelated but Ill pull the code to be sure.

I only really did that to get the fluid to cycle fully through the gears (straight ahead for about 1/4 of a mile).

A tad bit more fluid in the transfer case isnt going to hurt anything, right? It was just below the fill port when I cracked it open, so maybe 200ml more fluid.

 

A little extra fluid is ok. Now find out what the code is.

 

If you used the Supertech ATF+4, it's as good as any other. ALL licensed ATF+4 us the same; Chrysler specifies that it be made from a specific Grp III basestock purchased from 1 of 2 companies, and a specific additive pack. This assures that ATF+4 purchased from WalMart, or NAPA, or the dealer, etc will all perform the same.

http://www.centerforqa.com/

http://www.centerforqa.com/licensedatf4brands.html

 

Nice, thats good to know.
I did read that somewhere but I have to believe that Supertech's QC is not as good as say Royal Purple's is.

Thanks for the help guys - I thought the CEL might be related but I doubt that it is.

 

I thought the proper fluid for the tranny and TC is Dex III/Merc. I'm sure about the tranny.

 

I don't think the 5 speed takes dex/merc. The auto does. But I do know you don't put atf+4 in a transfer case. Or the auto trans.

 

As long as it's a good quality ATF, the transfer case doesn't care if it's Dex, ATF+4, or even Type F. The difference between the fluids is the amount of friction modifiers, which only affects clutch materials (none in the transfer case).