Rear Diff w/ Carbonetics LSD

[minus500]

What is the spline count for the rear differential side shafts on a US Spec 1993.5 TT Automatic? Info is very limited on this subject. The one article I did find had them listed as 30 spline. Kaaz, Carbonetic, etc all state that their lsd's will only work in Open/Auto TT differentials with 30 spline side shafts. Can anyone elaborate on this?

[BamaDave]

I’m not sure you’ll get a good response here; you might consider doing a search specific to the Carbonetics LSD and PM the different owners as well as email them, also you can catch them trough Twitter or tech support at 310-635-3555.

[Wreckless]

What is the spline count for the rear differential side shafts on a US Spec 1993.5 TT Automatic? Info is very limited on this subject. The one article I did find had them listed as 30 spline. Kaaz, Carbonetic, etc all state that their lsd's will only work in Open/Auto TT differentials with 30 spline side shafts. Can anyone elaborate on this?

The 200mm open and 200mm Torsen LSD stubs are different but the spline count is the same. The difference is that the OEM Torsen LSD stubs fitted into an aftermarket LSD or open diff will be slightly too long. The inherent slop in either CV axle is enough to compensate but it's not ideal for longevity of the CV axles. Some people have had issues with the axle stubs popping out of a TRD LSD slightly when used with the TT auto LSD stubs, especially after severe wheelhop.
The best solution is to go to your local Pick n pull junkyard and pull the axle stubs from a 92-97 SC300 or 92-97 SC400 as those axle stubs will be from an open diff 99.9999% of the time. If the SC400 is fitted with traction control, the CV axles are worthy for use as spares in a TT auto or NA-TT using a 200mm rear diff carrier, and depending on the year, might be beefier than your existing TT auto axles. Use a caliper and measure the shaft thickness to be sure.
An early GS300/GS400 might also use the correct open diff axle stubs but double check the bolt spacing on those stubs (wouldn't be a bad idea to check the SC's as well, I haven't gathered solid information for all model years of SC's yet) as some axle stubs used a smaller bolt pattern in later years, particularly in 2JZ-GE models. The change seems to correspond with the adoption of VVTi engines but I'm not 100% sure on that. Basically, the earlier the model, the more likely it's what you want!

[minus500]

Thanks guys. Carbonetic and Kaaz both have special notations saying that their diff must be used in Open/Torsen Auto rears with 30 spline side shafts and that models prior to 96 with 35 spline side shafts need a different LSD. I really don't wanna have to pull my diff just to find out that they are 35 splined. Mine is a 93.5.

Check this link to see what I'm talking about. http://www.carbonetic.net/match/usa_lsd_toyota.html

I'm wondering whether I should just go TRD or stick with the Carbonetic LSD? The thing that bothers me about the TRD is that it's 2 way. I think for my purposes and experience a 1.5 way would be better which steers me towards the Carbonetic LSD.

PS - Wreckless, did you ever find out about the late model GS300 differentials and the possibility of a 3.615:1 gearing? My research indicates that they don't have this and that it was only offered on a middle eastern version of the gs300.

[Wreckless]

Thanks guys. Carbonetic and Kaaz both have special notations saying that their diff must be used in Open/Torsen Auto rears with 30 spline side shafts and that models prior to 96 with 35 spline side shafts need a different LSD. I really don't wanna have to pull my diff just to find out that they are 35 splined. Mine is a 93.5.

Check this link to see what I'm talking about. http://www.carbonetic.net/match/usa_lsd_toyota.html

I'm wondering whether I should just go TRD or stick with the Carbonetic LSD? The thing that bothers me about the TRD is that it's 2 way. I think for my purposes and experience a 1.5 way would be better which steers me towards the Carbonetic LSD.

PS - Wreckless, did you ever find out about the late model GS300 differentials and the possibility of a 3.615:1 gearing? My research indicates that they don't have this and that it was only offered on a middle eastern version of the gs300.

Not yet. As I'm sure you've noticed, information regarding the various differentials installed in all of these Toyotas through the 90's is cryptic and spotty at best. My recent trip to my local u-pull yard did have a '98 GS300, but the differential had already been pilfered. As soon as I find a GS300 to check out in depth, I'll be sending you a PM for sure.

As for the spline count difference, that might also account for the differing bolt pattern size on the axle stubs as well, which started happening during late '96 or early '97 - speaking actual date of production, not model year.

[minus500]

I spoke with a rep at Carbonetics and even he was unable to tell me whether it is 30 or 35 spline side shafts in the Auto TT diffs. He did say that he thought that 30 spline was probably what I had but that he couldn't be sure and that I should just disassemble it to confirm. I really don't wanna do that so we'll keep this thread alive until there is some sort of definitive answer.