98 4WD. I think it's a 64HD, I'll have to go look again and make sure. I noticed it didn't want to shift so I looked under the truck and saw it leaking, so I'm gonna top it off. I've that it can take both ATF3 and ATF4, but that doesn't seem right.

 

it can...might as well put atf4 in it. does the same thing and is more available i think. you can go up in rating, but not down. regardless, i dont think your transfer case is a 64HD...depending on what model and year you have, i think the numbers are like 231d/hd or something like that. there should be a little round metal tag on your transfer case that tells you exactly what model it is.

 

1500 will be a 231. the proper fluid is atf+4, which supersedes 3. your owners manual probably calls for 3, but its unlikely you'll find any. 4 is better. it only takes about 1 qt to fill it. drain/fill plugs on mine are 10mm inside hex. be careful using a 3/8, it'll strip it. use a bolt head if you don't have a hex.

if its not shifting, you may have a bigger problem than low fluid.

 

Yep, 231. It will shift, it just doesn't want to. I bought it from my Grandfather, and he said it had been a LONG time since it had been changed. If I do have a bigger problem, it will have to wait. I blew all my $ on a plenum fix. How much hassle and cost is it to rebuild the case?

 

not much...but it was easier and took a lot less time for me to buy a used transfer case from a certified parts dealer and just swap them out. oh and the drain plug and fill plug on my transfer case is definitely a 30mm...holy crap.