auto tt lsd for sc300
03-11-15, 09:43 PM
#1
Driver School Candidate
Thread Starter
auto tt lsd for sc300
I have come across a deal with a auto tt differential from a mk4 supra for my sc300. Im here to see what i should be looking for before i buy it, the vendor has told me so far its a 2 way lsd, and its 2.0?
03-12-15, 04:03 AM
#2
Hello and welcome, cabrerajzz!
Good find! These are not easy to come by.
If it's a genuine 3.769:1 ratio TT Auto 200mm differential then it sounds like the original Torsen 1.5-way geared LSD was removed and either a TRD 2-way, Kaaz 2-way or other 2-way clutch type LSD was installed. It could have also been one of the 1997-1998 TT Auto differentials that were not optioned with the Torsen from the factory.
Rule of thumb with stock TT Auto LSDs is that you should be allowed to see a picture of the inside to verify it has a Torsen and not an open diff. The reason for this is that a Torsen acts exactly like an open differential when you apply the turning test. It only acts like an LSD when it's operating loaded in the car with both wheels on the ground.
1993.5-1996 Supra TT Automatic vehicles came standard with Torsen LSDs
1997-1998 Supra TT Automatic vehicles came with open diffs standard and had to be optioned with the Torsen LSDs at the time the cars were ordered from Japan. Some were optioned and some weren't.
Since he's specifically telling you the LSD is a 2-Way this means it's an aftermarket clutch-type. Technically this is considered an upgrade if it's a TRD, Kaaz, Cusco or OS Giken. 2-Ways have their own driving quirks during turns but are considered more predictable and safer than factory gear type Torsens at 500whp and above.
So:
1.) If it's just a factory TT Auto LSD you should be allowed to see a picture of the inside of the pumpkin with the rear cover off.
2.) If it's a 2-Way aftermarket clutch-type LSD you should be able to apply the wheel turning test to verify it's an LSD. Or the seller could show you a picture just the same.
Market ballpark price a few years ago for a stock TT Auto pumpkin with the factory Torsen was $900-$1,000. I'm not sure what people value 2-Way TRD LSD swapped diffs at.
Also, all TT Auto and Supra MKIV pumpkins should have cooling fins cast into the exterior instead of the smooth casing Lexus vehicles come with. Both casings are equally strong but this is what it should look like.
Good find! These are not easy to come by.
If it's a genuine 3.769:1 ratio TT Auto 200mm differential then it sounds like the original Torsen 1.5-way geared LSD was removed and either a TRD 2-way, Kaaz 2-way or other 2-way clutch type LSD was installed. It could have also been one of the 1997-1998 TT Auto differentials that were not optioned with the Torsen from the factory.
Rule of thumb with stock TT Auto LSDs is that you should be allowed to see a picture of the inside to verify it has a Torsen and not an open diff. The reason for this is that a Torsen acts exactly like an open differential when you apply the turning test. It only acts like an LSD when it's operating loaded in the car with both wheels on the ground.
1993.5-1996 Supra TT Automatic vehicles came standard with Torsen LSDs
1997-1998 Supra TT Automatic vehicles came with open diffs standard and had to be optioned with the Torsen LSDs at the time the cars were ordered from Japan. Some were optioned and some weren't.
Since he's specifically telling you the LSD is a 2-Way this means it's an aftermarket clutch-type. Technically this is considered an upgrade if it's a TRD, Kaaz, Cusco or OS Giken. 2-Ways have their own driving quirks during turns but are considered more predictable and safer than factory gear type Torsens at 500whp and above.
So:
1.) If it's just a factory TT Auto LSD you should be allowed to see a picture of the inside of the pumpkin with the rear cover off.
2.) If it's a 2-Way aftermarket clutch-type LSD you should be able to apply the wheel turning test to verify it's an LSD. Or the seller could show you a picture just the same.
Market ballpark price a few years ago for a stock TT Auto pumpkin with the factory Torsen was $900-$1,000. I'm not sure what people value 2-Way TRD LSD swapped diffs at.
Also, all TT Auto and Supra MKIV pumpkins should have cooling fins cast into the exterior instead of the smooth casing Lexus vehicles come with. Both casings are equally strong but this is what it should look like.
03-12-15, 08:32 AM
#4
Kahn hit the nail on the head.
Steve
Steve
03-12-15, 06:24 PM
#5
Hello and welcome, cabrerajzz!
Good find! These are not easy to come by.
If it's a genuine 3.769:1 ratio TT Auto 200mm differential then it sounds like the original Torsen 1.5-way geared LSD was removed and either a TRD 2-way, Kaaz 2-way or other 2-way clutch type LSD was installed. It could have also been one of the 1997-1998 TT Auto differentials that were not optioned with the Torsen from the factory.
Rule of thumb with stock TT Auto LSDs is that you should be allowed to see a picture of the inside to verify it has a Torsen and not an open diff. The reason for this is that a Torsen acts exactly like an open differential when you apply the turning test. It only acts like an LSD when it's operating loaded in the car with both wheels on the ground.
1993.5-1996 Supra TT Automatic vehicles came standard with Torsen LSDs
1997-1998 Supra TT Automatic vehicles came with open diffs standard and had to be optioned with the Torsen LSDs at the time the cars were ordered from Japan. Some were optioned and some weren't.
Since he's specifically telling you the LSD is a 2-Way this means it's an aftermarket clutch-type. Technically this is considered an upgrade if it's a TRD, Kaaz, Cusco or OS Giken. 2-Ways have their own driving quirks during turns but are considered more predictable and safer than factory gear type Torsens at 500whp and above.
So:
1.) If it's just a factory TT Auto LSD you should be allowed to see a picture of the inside of the pumpkin with the rear cover off.
2.) If it's a 2-Way aftermarket clutch-type LSD you should be able to apply the wheel turning test to verify it's an LSD. Or the seller could show you a picture just the same.
Market ballpark price a few years ago for a stock TT Auto pumpkin with the factory Torsen was $900-$1,000. I'm not sure what people value 2-Way TRD LSD swapped diffs at.
Also, all TT Auto and Supra MKIV pumpkins should have cooling fins cast into the exterior instead of the smooth casing Lexus vehicles come with. Both casings are equally strong but this is what it should look like.
Good find! These are not easy to come by.
If it's a genuine 3.769:1 ratio TT Auto 200mm differential then it sounds like the original Torsen 1.5-way geared LSD was removed and either a TRD 2-way, Kaaz 2-way or other 2-way clutch type LSD was installed. It could have also been one of the 1997-1998 TT Auto differentials that were not optioned with the Torsen from the factory.
Rule of thumb with stock TT Auto LSDs is that you should be allowed to see a picture of the inside to verify it has a Torsen and not an open diff. The reason for this is that a Torsen acts exactly like an open differential when you apply the turning test. It only acts like an LSD when it's operating loaded in the car with both wheels on the ground.
1993.5-1996 Supra TT Automatic vehicles came standard with Torsen LSDs
1997-1998 Supra TT Automatic vehicles came with open diffs standard and had to be optioned with the Torsen LSDs at the time the cars were ordered from Japan. Some were optioned and some weren't.
Since he's specifically telling you the LSD is a 2-Way this means it's an aftermarket clutch-type. Technically this is considered an upgrade if it's a TRD, Kaaz, Cusco or OS Giken. 2-Ways have their own driving quirks during turns but are considered more predictable and safer than factory gear type Torsens at 500whp and above.
So:
1.) If it's just a factory TT Auto LSD you should be allowed to see a picture of the inside of the pumpkin with the rear cover off.
2.) If it's a 2-Way aftermarket clutch-type LSD you should be able to apply the wheel turning test to verify it's an LSD. Or the seller could show you a picture just the same.
Market ballpark price a few years ago for a stock TT Auto pumpkin with the factory Torsen was $900-$1,000. I'm not sure what people value 2-Way TRD LSD swapped diffs at.
Also, all TT Auto and Supra MKIV pumpkins should have cooling fins cast into the exterior instead of the smooth casing Lexus vehicles come with. Both casings are equally strong but this is what it should look like.
03-12-15, 09:03 PM
#7
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03-13-15, 01:34 AM
#8
CatManD3W, I feel your pain. You just have to keep looking and checking the SF forum classifieds. I looked for about a year before I finally snagged one. It was a full fourteen hour trip to pick it up in person. I missed many, many opportunities by mere hours and in some cases a mere hour because I hadn't checked the classifieds just a bit sooner. Unfortunately TT Auto Torsens really do get snatched up THAT quickly.
Alternatively you could invest in a TRD 2-Way LSD and have that installed. It would depend on your driving style though.
Alternatively you could invest in a TRD 2-Way LSD and have that installed. It would depend on your driving style though.
03-13-15, 11:03 AM
#9
CatManD3W, I feel your pain. You just have to keep looking and checking the SF forum classifieds. I looked for about a year before I finally snagged one. It was a full fourteen hour trip to pick it up in person. I missed many, many opportunities by mere hours and in some cases a mere hour because I hadn't checked the classifieds just a bit sooner. Unfortunately TT Auto Torsens really do get snatched up THAT quickly.
Alternatively you could invest in a TRD 2-Way LSD and have that installed. It would depend on your driving style though.
Alternatively you could invest in a TRD 2-Way LSD and have that installed. It would depend on your driving style though.
03-23-15, 09:07 PM
#11
Jumping over from the SC430 forum ... I am swapping the OEM differential for a Supra TT LSD 3.769 differential from a 1998 Supra TT. It is suposed to be from an auto tranny but it has the smaller companion flange and doesn't match the large flange on the SC430. There is a 10 mm difference in the distance between the far edges of the bolt holes (102mm vs 112mm on the SC430).
I am reading in this thread that the flange difference is well know to you all. HELP - how do I get the pinion nut off? I saw that the nut is crimped to a groove in the pinion so it doesn't move once the preload is calibrated so I puched out the crimp by hammering a screwdriver in there. However the nut still doen't move. I am using a 34mm deep socket and an impact torque wrench.
Any tips?
Thanks much
Pd. FYI I am upgrading with the poly pinion ear and rear bushings from Figs.
I am reading in this thread that the flange difference is well know to you all. HELP - how do I get the pinion nut off? I saw that the nut is crimped to a groove in the pinion so it doesn't move once the preload is calibrated so I puched out the crimp by hammering a screwdriver in there. However the nut still doen't move. I am using a 34mm deep socket and an impact torque wrench.
Any tips?
Thanks much
Pd. FYI I am upgrading with the poly pinion ear and rear bushings from Figs.
03-24-15, 05:08 PM
#12
SlvBullet,
The bushing upgrade is good but the companion flange issue from TT Auto to SC430 is something I am not familiar with. I remember hearing that it's not uncommon for SC430 owners to swap Supra TT Auto LSD rear diffs into their cars but I never looked into just how this was done.
I recall using a 35mm deep socket and a DIAL TORQUE wrench. That's a crucial wrench type to use in his case when you swap over whichever companion flange is correct. You do not want to over or under torque the flange as it will either be too loose or too tight beyond the Supra FSM specs and could affect the pinion alignment with the ring gear internally. A normal torque wrench can read far too high into ft-lbs for use on a companion flange nut.
The bolt hole alignment is similarly why we swap SC companion flanges onto TT Auto diffs. Is there an issue with the depth of the SC430 flange not fitting into the diff correctly at all?
As for the 35mm nut, it's a good idea to obtain another one but depending on the condition you should be able to reuse the original one.
The bushing upgrade is good but the companion flange issue from TT Auto to SC430 is something I am not familiar with. I remember hearing that it's not uncommon for SC430 owners to swap Supra TT Auto LSD rear diffs into their cars but I never looked into just how this was done.
I recall using a 35mm deep socket and a DIAL TORQUE wrench. That's a crucial wrench type to use in his case when you swap over whichever companion flange is correct. You do not want to over or under torque the flange as it will either be too loose or too tight beyond the Supra FSM specs and could affect the pinion alignment with the ring gear internally. A normal torque wrench can read far too high into ft-lbs for use on a companion flange nut.
The bolt hole alignment is similarly why we swap SC companion flanges onto TT Auto diffs. Is there an issue with the depth of the SC430 flange not fitting into the diff correctly at all?
As for the 35mm nut, it's a good idea to obtain another one but depending on the condition you should be able to reuse the original one.
03-30-15, 05:40 PM
#13
Thank you very much for the information. I completed the project and the car feels like it wants to jump out of its skin! It turned out that the late model Supra TT differentials can have one of three possible flanges and only the 'large' flange fits the OEM SC430 drive shaft. The diff I recieved had a flange 10mm smaller between mounting holes. I also learned that the nut that holds the flange in is crimped so that has to uncrimped. Lastly the impact deep 35mm socket I have was too fat to reach the nut and a thin wall socket has to be used. I ordered the correct matching flange and a new nut and had the motorsport shop I use (Mach V) to replace the flange and apply the proper torque. Great idea anout the dial torque wrench - I need to get one of those.
No problem with the install and fitment once I had the correct flange.
No problem with the install and fitment once I had the correct flange.
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