Does a 1997 Dodge 3500 RamVan's Rear Diff. require special fluid ?

Absolutely. The only thing "special" is a limited-slip additive, if you have a limited-slip rear. Any parts store will carry this, and the D70 axle takes about 8oz. of additive. If it turns out that you need this (ie. you have a limited slip differential), you'll need to either suck some fluid out from the fill plug hole, and add the fluid, or just jack the rear end up (or park on a hill, nose-low) and add the fluid (an extra 8oz. won't hurt anything).

If you don't know if you have a limited slip differential or not, put the van in park, jack up the rear, and spin a rear tire. If you can spin it (with the other tire spinning in the opposite direction), you do NOT have a limited slip. If you can't turn the tire, then you DO have a limited slip, and should add the modifier to prevent clutch chatter (ratcheting noise coming from the rear end while going around corners).

Good info. Thanks.

Dave; why are you posting as fast1970Vette *and* DaviinLakeVilla? Have you got some hidden agenda of perhaps answering yourself and agreeing totally just in case everyone else thinks you're talking out of the wrong hole? As they say; there's nothing new under the sun!