i have two possable torsen posi units. can someone please post some detailed pictures of a Torsen Zexel posi unit from a Camaro/TA that is not a heavy duty posi from SLP. Where would the part number be located on the posi unit. here are some numbers i have pulled from the side of the differentail case : D8 24 24 : K5 13 316 : 15D8 : UC-

not that this helps you a whole lot, but mine didn't have any numbers on the sides........ok so a cylinder doesn't technically have sides... Anyway, all the numbers were on the ends......but the couple pictures i took of it arent' good enough to pull any numbers from

I know it's an Auburn posi. what kind of auburn posi it is i dont know? i was told it came from an 98 fbody, its 28 spline is all i have to back that up.

First off, I may be a bit long winded, and it may take two replies to get the text & pics posted. Your original post asked about Torsens, then the second one mentioned Auburns.

First, this pic is of the two Torsen units used on F-bodies.

One on left is the oem Torsen (same as SLP take-off). Unit on the right is the HD TOrsen. Notice the difference in the paddle (cross-pin) design. The HD case is also more solid (thicker) where as the oem one is thinner and uses ridge castings for strength. Also, the HD unit has a solid flange for the ring gear, where as the oem Torsen has a scallopped thickness. These three features alone will ID the Torsen.

I'll post something on the 4th gen Auburn in a minute.

When I was looking at a fourth gen axle for my 92, here was a bit of info I was looking at since the donor axle suppossedly came from a 2000 SS that would have had the SLP Auburn (Turned out to be a std Auburn). These notes are from my e-mails back & forth with one of Auburns's engineers:

Auburns have the taperd cast body, with a round cross-pin instead of the rectanular paddle that Torsens use.

Following my conversations with Auburn engineering, the numbers cast and marked on the outside of the unit have little/no significance to help ID a std Auburn (from older years once Torsens became the oem offered diff) from the SLP unit. Some of the changes are visible, some are not.

These changes were specifically for better performance and durability for heavy cornering/autocrossing.

Basically, the oem Auburn has a standard set of pre-load springs inside the unit along with standard cone clutch angles. The HiPerformance series Auburn contains the standard cone clutch angles, but alters the pre-load springs to include 5 stiffer yellow springs which increases the holding power of the cone clutches. The Pro Series Auburn has 3 of the preload springs changed to even stiffer orange springs. The SLP Auburn unit is different in that it too uses the same yellow pre-load springs as the HiPerformance unit, but the angle of the cone clutch was changed to increase the speed of clutch engagement (agressiveness) and holding power. Additionally, the holes for the cross pin on all of the standard Auburn units are close tolerence fit holes, where the SLP unit is slotted by about .030" per side. This allows the pin to "float" side to side on the retaining screw shoulder during cornering. This prevents the end (against the pin) of the outboard axle shaft during a turn from exerting pressure upon the pin, which would then put stress & strain upon the Auburn case. This distortion can lead to failure.

its an Aubrun all right. spring type posi and the Auburn logo cast into the side of the case. If i understud what you said properly, i have a Auburn Hiperfromance serise posi because it has the agressive (yellow) but not too agressive (orange) springs also my pin has no room for play. if i bored and honed the hole for the pin, would that be the same as the SLP Auburn aside from changing the springs? basicaly if i want to reduce stress from the pin could i just drill the hole 0.030" bigger? Thanks for the help!!

I have the Heavy duty Zexel Torsion diff in my car now. It works,
but since I have a tweaked suspension, I can't light them up
like I used to.

In addition to the differances between the OEM "take off" unit
and the "H.D." SLP unit, is that the SLP HD one has all gears
inside of it, NO springs like the Auburn unit. Also, has two
times the amount of gears for posi ( friction?) than the
OEM take off unit.

Also, the SLP H.D. diff. is about $400 more! You get
what you pay for.

Just to clarify a point:

Around 96, GM still had the oem syle Auburn in the standard axles, and SLP/GM offered the HD Torsen as an option on the SS (FireHawk & Ram Air I recall too) cars. About 2 years later, GM had switched to the Torsen oem diff, and was offering the Auburn (spec'd out by SLP) as an option.

Both the oem Torsen used by GM and the HD Torsens use what Xexel/Gleason (Mfr of the Torsens) calls an Invex Helix geared type differential, not a cone clutch type like the Auburns.

This is correct! My friend's 1998 Trans Am has the Auburn
unit. We noticed that when he decided to replace his
3.42s to Richmond 4.10s. I had noticed that the unit
had springs in it ( yellow). I know that these are capable
to withstand some power. But for my 3rd gen, I went with
the H.D. SLP unit just as a back up, since those were put in
345 rear wheel hp Firehawks and Camaro SSs. My motor
is estimated at 290-300 rear wheel hp/340 rear wheel
torque, but I always like to "beef" up everything around it,
just in case!