Bout to do a drain and fill on transmission fluid (99 with 160K). I know to check the level at normal running temperature before draining. On the refill, does the jeep need to be running? I've read some different threads that has made this point unclear to me. Thanks.

 

It doesn't need to be running while filling.
I think it takes 3 3/4 qts. Put 3 1/2 in and drive it.
Check it when hot.

 

Not correct. It needs to be running. It will only take about a quart or so before it runs out of the filler tube if it is not running.

I found out.

In addition, drain and refill on my '92 took about 2.5 quarts each time. I did it 5 times over a period of 300-400 miles or so.

 

Kingfisher is right on.

I'd just add that the reason you need to check it running (as opposed to how you'd check the engine oil) is because there's a fluid pump inside the transmission that pumps the fluid all around when it's running. Some transmissions don't run the pump in Park, so that's why they recommend checking it in Neutral sometimes. IIRC, the AW4 runs it in both P and N.

In any case, there's no accurate way to get a good fluid level reading with the engine off, as the fluid will gradually drain out of the TC and valve body (some of it, anyway) over a period of several days. That's why you need to do it when the pump is running. It should be hot, as the fluid expands as it's heated.

For contrast, the engine oil all drains back to the pan shortly after you shut the engine off, so that's why you can check it while off. My understanding is that it's all sitting in the pan, so the level won't change much hot vs. cold, unlike that trans that's filled with all sorts of small passages with most of the fluid in circulation rather than sitting in the pan.