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

I have a true trac trac tec installed in my 82 242Ti. I had a local 4wd truck
specialty shop install it. The differential is a 1031 model if it came from a turbo model 240. Basically what you have been told is correct. The ring gear and
the pinion are different from the 1030. The differential does fit the 1031 axle and ring and pinion.
I purchased an installation kit and when performing the install the shop needed
a new bearing or race for the pinion. I don't know the number but they sourced
it from timken. Just be sure the diff is matched to the ratio. There are different diff models for the available ratios. The turbo wagon rear is the 3.73 1031 model. The worse the weather gets the more fun my car is to drive.

If your V8 is really built up I recommend you take it easy on the diff if you are going to use really sticky tires. The Dana 30 is not a large really strong rear and the gears in the trac tec aren't as big and strong as say in a Dana 44. I can't say how much torque the rear can take but the shop that installed mine said it is a really strong rear. Just not as strong as a bigger one. ATB diffs are great! One of the best improvements I've made to my car. I've got about 30k on mine and it shows no sign of any problems. I drive my car enthusiastically every day. This is also the time to replace the rear wheel bearings and seals. Have them packed with a high quality synthetic grease like
Redline. The rear wheel bearing should be packed with grease.

Dave 82 242ti 278k mi.

Interesting thought; I don't have the length of a Jeep Axle (must be close)but all the older models have Dana 44's and most with 3.73 gears in the rear. Grind off the perches and weld on the Volvo mountings. good to go. Hmmm

I've busted my spider gears in the Jeep but I'm spinning up 33" tires with a healthy Chevy 350 and it's non posi.
A Dana44 with Volvo sized tires, and Tru Trac, I bet you can smoke the tires off the car without problems.
--
'75 Jeep CJ5 345Hp ChevyPwr and two motorcycles: it wasn't Volvos safety , it was Longevity that sold me

Hi Tony,
I believe the front diff on your Jeep is also a Dana 30. The rear diff is a Dana 44. When I was looking up my tru trac it listed the Dana 30 as the front diff on
Jeep CJ models. I have a 1966 MGB GT with a Jeep rear adapted to it. It looks
bigger than my Volvo rear so I believe it's got a Dana 44 in there. I've seen
Volvo 240s that people have adapted Ford 9" rears to by adapting the mountings.
They get the ones from the 80s Lincolns and the turbo model Tbirds with the rear disc brakes.

You really have to be careful with the sticky tires that are available. They
grip the road so well you have to be careful not to trash your driveline. I'm
using Bridgestone Potenza S-03 tires and they are definitely a tire with
incredible performance. Even in the small 205/55-15 size that I run.

Dave 82 242ti 278k mi.

I have a TrueTrac in my 745T. You will be happy with it! I had the install done by a 4X4 shop. 240 turbo cars are supposed to have the 1031. On the 700 series there is a decal on the rear of the left axle tube that lists the axle type and part number. Usually this decal is covered by undercoating and crud. I use a rag and solvent to carefully remove the undercoating so I can read the numbers.