How do I tell a Dana 80 from a Dana 70HD ? I've seen the pics @ Randy's but I'm still uncertain. I do have the VIN printout (courtesy of this great website) and I believe it has the optional 4.63 rear gears (correct, according to my "dream wheel", if I have 33" tall tires :( ). No mention of a locker or LSD !?

A D70HD has D70 stamped right on it. A D80 may or may not. You should have a D80 in that 3500HD.

Thanks , I suspected so much. I'll definately look into it further before purchasing anything for it.

4.63 gears = I need a min. 34" tire instead of these 32" :(

(4th gear pulls cleanly from 30 mph & up, can use third if you're going to just roll the stop sign ):h ! )

Don't all 3500HD have the D80?