MannyZ28

iTrader: (1)

I have been doing searches on here, but really never got the answer I am looking for. It seems to me that just about every 98 car has a Auburn diff, while the 99 and up cars got the Torsen diff. I did read somewhere that a few SS's had the upgraded Auburn diff. I know the difference between the two is the absence of a clutch pack in the torsen, but which of the two is really the more desirable rear end, and why did GM decided to abandon the Auburn in 99 in favor of the Torsen?

Does anyone know?

BillS

iTrader: (13)

Ok, Pre 99 the std diff in all Z28/SS cars was the base auburn. On all SS cars up to 99 they offered both a heavy duty auburn and a torsen( heavy duty, but same bias ration as the 99+ oem) as an optional upgrade.
In 99 the lighter duty torsen became OEM . SLP then only offered the heavy duty auburn as the upgrade

GM dumped the auburn due to Warrantee claims. It was not uncommon for a oem auburn to wear out in 20k or less. Competive autoxers were eating 2-3 a season. The torsen works roughtly the same for its entire life, instead of progressively less each day like the auburn. The down side of the torsen is that GM had the torsen "cheapened" when they took it as a OEM diff. The bias ratio stayed the same as that was a function of the pitch of the gears, but they decreased the number of worm gears in the design. So if you over task a oem torsen you are more likley to have a total failure.

The auburn design uses a cone shaped friction material that rubs directly on the inside of the case of the diff carrier. If you excede the grip if the friction material it slips, so you tend not to have the total diff failure in an overpower situtition, but the grip of the cones weakens constantly.
Also the Auburn is not rebuildable like a ford trac-loc becaude the case itself is worn away by the cone friction material, as the ford unit uses replaceable steel plates and friction disks. the upgraded Auburn uses grippier friction cones and stiffer springs forceing them into the case, but when it is worn it is still trash, unrebuildable.

Torsen also makes the T2R diff which is much beefier in its design and has a much higher bias ratio. It has great steet manners but is much more expensive , due to the larger and more numerous gears inside it. I have never heard of someone exploding a T2R like a oem torsen, as the rest of the 10bolt becomes the weak link.

Geared diffs like the torsen and the tru-track have great life, but they are not immune to wear, Some roadracers have seen the gears inside them wear
causeing the noise to increase and seen them develope some slop internally.
Dragracers hit a diff with a shockload, more on stick cars then autos, That tends to find the weak link in your drive train The auburn type diff will slip if overpowered, where as a gear diff will explode. The tru-track diff is working well in many high hp cars because it is built like a tank, but if it is overpowered and is the weakest part in the driveline then it will go boom too

I have had and raced ( drag and autox) the auburn, oem torsen, slp torsen, T2R torsen and now a tru-track in my camaro And I will say the T2R was the best in autox, but the tru-track is close there and it has had no issues on the street and strip. I ate up the auburn X2 is no time and the oem torsen, due to its lightening up, you were able to get it to unlock in tight rt turns underpower, not good in a autox. I never ran the SLP torsen as it cost the same as my T2R at the time.

MannyZ28

iTrader: (1)

Thanks for that explanation...I had no idea. In a way, I am happy that I have the Auburn since, according to what you wrote, it won't explode but just slip and fail gradually. Since I don't auto x or take my car to the track, I will probably have a pretty long life with my Auburn and won't have to deal with my rear end detonating with a Torsen.