Tcase and Transmission fluid change

[fony3]

I am hoping to do an oil change in my tcase and transmission this weekend and just wanted to get a quick bit of advice....

My transfer case is a NV231 and I am finding lots of options/opinions on oils. I have found people using ATF+3, ATF+4, Dexron 3 and possibly dexron 4. Is there a big difference between these four, i am guessing from 3 to 4 is just higher performance? Which will be better suited?

I am also wondering if I should drop the skid plate or not, I am guessing its a lot easier just to skip that step and use the drain holes, just makes a bit more of a mess?

The transmission is an NV-3550, and i have read that I need a syncromesh transmission fluid...Anyone know offhand if I can buy the pennzoil anywhere, or if the GM dealers carry it.

Thanks in advance!

[TheCaptain]

-Head on over to Mopac Auto Supply on 16ave and pick up 4 quarts of Redline MTF or MT90 (your pick).  Well worth the extra bit of change in the long run for your transmission.  It's exactly what you'll need. 

In regards to dropping the pan, I didn't have the time nor proper setup to drop it.  Just drain it into the skid plate and make sure you have a LARGE oil pan to cover it.  You can never tell where the fluid is going to find a low spot to drip down from.
Once you've drained/filled everything up take a can of brake cleaner to the skid plate and let that do most of the cleaning.  After that grab some blue shop towels and give it a wipe down.

Tada!!

And make sure to do everything well ventilated.  The brake cleaner fumes are nasty.