How do the transfer cases handle different rear gears?

I've got 3 diffs. One is a claimed gvr4 open (3.545). One is a viscous 3bolt (3.307). And the other is a viscous 4bolt (3.545) The 3bolt viscous works good (bolt spin the same direction immediately). The 4bolt locks after a full rotation (bad or worn coupler I imagine).

What should I be running? I know if it's a 4x4 you shouldn't mix differential gearing. But I'm not sure how AWD cars compensate?

My transfer case is a 23 spline (half aluminum, half cast)

The sticker I found on the trans is a barcode which states: BNH1752-NPXV

 

[Barnes]

You have to run the same ratio as the front differential.

 

How do I find out what the trans is?

 

[JNR]

there should be a code etched on the transmission near the bellhousing that begins with W, iirc...If you do a search on here, somebody had posted up the different codes on the various transmissions; bet it's in the how-to/info section...

But yeah, as mentioned, need same gear ratios front and rear, plus the same sized tires (OD) all around, or at least within say 1/8-1/4".

 

[pauleyman]

The transfer case doesn't care what you run but mitsubishi in their infinite wisdom did mix and match front, transfer and rear diffs depending on 5spd or auto and made an additional switch on 97 up dsm. I have no idea why they did this but they did. You must run a matched set of the three. 90-96 dsm and gvr4 5spd should all be the same for all 3, as far as ratios are concerned. There is of course the spline count difference for 90.

 

[doggietom]

I believe the 3.545 is manual and the other is for a automatic Trans