Seems like the more I get into this, the more confusing it gets. I ordered a TrueTrac limited slip from Reider Racing for my car several months ago. I'm about ready to install (or to help a knowledgable friend install) so I've begun asking questions and I've managed to confuse myself all over again. Thanks to all of you that responded to my previous post. My car is an 82 242 w/5.0L conversion. Originally it had a 3.54 gear; however, the previous owner swapped in a rear end out of an 84 turbo wagon to get the 3.73 gear. There doesn't seem to be any surefire way of distinguishing the 1030 rear from the 1031 short of pulling the diff and measuring the ring gear diameter - 1030 has 7.25", 1031 has 7.75". I guess the 1030 is a Dana30, while the folks at Reider Racing refer to the 1031 as a 'corporate Volvo axle'. The folks at Reider racing know the TrueTrac will work with the smaller ring gear, they have no idea if it will work with the larger ring gear. Apparently the pinion gear is a different length and diameter in the 1031 as well.

So, anyway of telling which rearend - 1031 or 1030 - came in the 84 turbo wagon? Anyone know for sure whether the TrueTrac will work in either or both rear ends? A few folks have told me they think the TrueTrac will work with either size ring gear (this would mean that the inner ring gear diameter and bolt pattern are identical between the larger and smaller gears), but that the pinion bearings and races are a different size than the standard Dana30/1030 pinion components, and must be sourced from Timken or Volvo. Assuming all turbo 240's came with the 1031, anyone installed a TrueTrac lsd in one? If so, any particular issues/problems? Any help unravelling this mystery is appreciated as I've already bought the unit, and am trying to figure out if it's going to work, before I pull my stock one apart. Thanks - M