From what I've gathered here, it looks like everyone with a 5 speed sc3 is recommended to get the mkiv supra tt automatic lsd. However, these two have a different gear ratio so doesn't that mean that the speedo would be off? Or am I missing something here? Thanks.

JM

 

Yeah the speedo would be off, but it would be very slight. Equivalent to running different sized tires, in the 5% range I believe. Further, the pluses outway this disadvantage. TT auto LSDs drop right into the sc without changing out axles or drive shafts. They are also cheaper than aftermarket options and since they are Torsen LSD that don't lock the axles in some kind of 2:1 or 1:1 ratio, they offer very nice street ride quality along with great traction off the line.

 

Ok, so swap your input shaft and ring gear and you have the same gear ratio. Most people dont necessarily want the same gearing anyway so they purposely change them.

 

On my SC400 I used a 1993 Supra TT Automatic LSD torsen and the gearing was exactly the same......I know this doesn't help you much, and I believe the manual sc300 and 1993+ Supra tt manual - LSD torsens won't match the casing bolt patters, you would need to change out the guts and use your stock sc300 Differential casing/pumpkin to make the swap work.. Now, I could be wrong on this manual swap stuff, but have read this manual swap on other threads....

I love my torsen and have been running on it for a year. It runs just like stock but instead of one wheel burnouts you now get two wheel burnouts, which I am sure you guys already know...Good luck...

 

The 6 speed diff (the actual LSD unit) is a 12 bolt design and the TT auto LSD/NAs are a 10 bolt pattern. All the SCs (300/400s, auto and manuals) use the 10 bolt pumpkin. So you will need an auto TT LSD to swap it into your stock diff case/housing. The auto TTs entire diff (housing/pumpkin) is a direct bolt-in and the 6 speeds is different from what Ive been told.

 

I used the auto supra TT diff, but I only used the carrier. I used the original ring, and pinion.
Took my pumpkin out of the car. took out the carrier. put the ring gear on the Torsen LSD carrier, and installed the Supra carrier with the stock gear back in the housing.

 

Cool, sounds good. Thanks for the info guys.

rdm20fan, what shop did you use in illinois for this? Thanks.

JM

 

Chrisman "Chris" is a good friend of mine.
He has a shop in Palatine.
He and I did it at his shop.

It wasn't a difficult job.
Took alittle time, but wasn't to hard.
Actually it took less time then I though it would.
3 hours maybe. I was thinking most of the day.

 

Cool. How did you find an used auto tt torsen differential? I haven't seen any mkiv supras in the junkyards around chicago and the suprastore doesn't carry the auto tt differential. Thanks.

 

www.supraforums.com and look for about 6 months.