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Bought a 4.1 N/A Supra LSD
bought a OEM 4.1 N/A Supra LSD full pumpkin for my stock 97 SC300 5 Speed (w58). Is it completely bolt on or can anybody provide tips or needs before I get started. Thanks in advance
john |
It is bolt in after you swap the companion flange (the spinning three-spoke input flange that connects to the driveshaft) for one from an SC300 or SC400. You can use the one from your original differential or you can find one in the classifieds or ebay. I would hang onto the Supra diff's original flange just in case you ever need to pair it with the diff again.
Key is that the Supra's companion flange has a 111mm spacing between each of the three ears while the SC (and Soarer) companion flanges have a 101mm spacing. It is subtle but critical which is why the correct flange for the car the diff will go into must be swapped on. There is an identical procedure for how to take the flange off and put one back on in both the SC300/400 and MKIV Supra TSRMs. Careful attention must be paid to the correct torque required using a dial torque wrench. This is to prevent upsetting the delicate balance of the internal ring and pinion alignment and mesh pattern-- you don't want to throw that off or you could damage the diff and gears once it's connected to a running car. A driveline shop should be able to handle this if you are uncomfortable with tackling it yourself. If you look up the TSRM procedure and don't feel comfortable that you can do it correctly, let a professional shop handle it. It's not a big deal and doesn't take long at all but it must be done right. Replacing the pinion seal on the diff during the companion flange swap since it's accessible at the same time is also a good insurance policy. As for removing a diff and installing another one, the rear of the car is jacked up and put on stands (or a lift), and a hydraulic jack or transmission/differential jack is propped under the differential. While locking the parking brake (and unlocking it as needed to rotate the axles for access) the six hex bolts on each side are loosened and removed with two bolt shims on each side. Order a few spare axle bolts to have handy on standby just in case they are needed. The main diff bolts at the rear and front ears are loosened and removed with the hydraulic jack supporting the weight of the diff (it is 90+ lbs so be careful). I don't recall the torque required to reinstall those bolts offhand but it's listed in the TSRM for the SC's and MKIV's-- all the 200mm diffs have the same torque values. The diff is lowered with the support of the jack (a solid block of wood for spacing under the diff can be used). Be slow and careful and ALWAYS keep the diff from wobbling or losing its balance so as to avoid it falling on the ground-- or on you. A trans/diff jack sometimes has metal side guides to avoid this. As the diff is lowered down the axles will drop from the sides of the diff. With the jack fully compressed, roll it and the removed diff out from under the car. Installation is in the reverse order. Again, make sure you use the correct factory torque values for diff installation. A torque wrench you know has good calibration is recommended. Harbor Freight sells $30 digital torque adapters in either 3/8" or 1/2" drive that can be used to roughly test torque wrench calibration accuracy if you're unsure of yours. I believe the side axle hex bolts are supposed to get 64 ft-lbs if memory serves but it has been some time since I looked at the TSRM pages for this. Since you are installing a Supra NA 4.083:1 Torsen LSD (this is often abbreviated to "4.1") into your car which came with a 4.083:1 open diff you will not need to use any aftermarket speedometer recalibrator (such as a YellowBox). In your case your speedometer will read exactly the same as stock. For diff oil it is the same as with your OEM open diff: regular 75W-90 diff oil (such as Mobil1 Synthetic if you prefer) or you can use Redline Heavy ShockProof diff oil. You shouldn't use any special gear oil with a "friction modifier" intended for clutch-pack LSDs. The Torsen doesn't need any special additives and doesn't benefit from them. It's all gear based and the internal Torsen unit itself never requires rebuilding. The factory change interval for open diffs and Torsens is every 30k miles. Other than that, you'll get used to the improved handling and just be aware that once you have a Torsen LSD in these cars you need to be mindful of driving carefully in the rain. Good high performance summer tires with a good rain traction rating and good reviews for wet traction are recommended. Lastly, enjoy! :) |
What great advice and guidance. This is the best of internet and thank you so much. I have a low milage 97 5 speed that i want to keep bolt on stock but Supra it up a little bit sound and handling wise.
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I am looking to install an LSD in my SC300 as well.
Great response, thanks for the detailed answer it saved me lots of search time. |
56k miles true 97 5speed. Will have it installed in the new two weeks.
https://cimg2.ibsrv.net/gimg/www.clu...c0ffe23aaa.jpg |
Very clean! Low miles and 5 spd, nice find! That LSD will make it so much more fun to drive.
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https://cimg3.ibsrv.net/gimg/www.clu...d509e33a5c.png
Got the car back with the LSD installed. Amazing OEM quality and a surprising amount of smoothness reintroduced with all the new seals and bushings. Amazing difference going from the open to the LSD. Not so much for the braided brake lines but can’t win them all. Tracking down the 97 Supra part to match fitment and the ratio was the right call https://cimg7.ibsrv.net/gimg/www.clu...5743401cae.png |
^^ Excellent, Crypto! It really is a significant difference, isn't it? Baffling that this was never standard or an option on the 5-speed SC's from Lexus.
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Originally Posted by KahnBB6
(Post 10036457)
^^ Excellent, Crypto! It really is a significant difference, isn't it? Baffling that this was never standard or an option on the 5-speed SC's from Lexus.
thank you again KahnBB6, you guidance was spot on and gave us the confidence to (sub out the flange and rebuild to a trans shop) :uh: having them rebuild and do it right made the rest Supra easy and give me peace of mind that the part was in good Knick. I do think Lexus missed an opportunity to have a part swap R model but guess they didn’t want to cannibalize Supra sales. Far and away the best mod I have ever done to a car. Just about done with the Lexus, I have the one I wish they had built from the factory. Now if only I could find a proper front strut bar. Low miles 1997 5speed Cat-back exhaust k&n drop in TEIN adjustable coil overs 18in 3 piece aluminum rims OEM LSD Stoptech Crossed drilled rotors and braided break lines yellow fogs and high beams TRD color matched stitching shift knob |
There is a JDM Chop house in Miami which is where I got mine.
100% recommend drag international |
Originally Posted by KahnBB6
(Post 10014881)
It is bolt in after you swap the companion flange (the spinning three-spoke input flange that connects to the driveshaft) for one from an SC300 or SC400. You can use the one from your original differential or you can find one in the classifieds or ebay. I would hang onto the Supra diff's original flange just in case you ever need to pair it with the diff again.
Key is that the Supra's companion flange has a 111mm spacing between each of the three ears while the SC (and Soarer) companion flanges have a 101mm spacing. It is subtle but critical which is why the correct flange for the car the diff will go into must be swapped on. There is an identical procedure for how to take the flange off and put one back on in both the SC300/400 and MKIV Supra TSRMs. Careful attention must be paid to the correct torque required using a dial torque wrench. This is to prevent upsetting the delicate balance of the internal ring and pinion alignment and mesh pattern-- you don't want to throw that off or you could damage the diff and gears once it's connected to a running car. A driveline shop should be able to handle this if you are uncomfortable with tackling it yourself. If you look up the TSRM procedure and don't feel comfortable that you can do it correctly, let a professional shop handle it. It's not a big deal and doesn't take long at all but it must be done right. Replacing the pinion seal on the diff during the companion flange swap since it's accessible at the same time is also a good insurance policy. As for removing a diff and installing another one, the rear of the car is jacked up and put on stands (or a lift), and a hydraulic jack or transmission/differential jack is propped under the differential. While locking the parking brake (and unlocking it as needed to rotate the axles for access) the six hex bolts on each side are loosened and removed with two bolt shims on each side. Order a few spare axle bolts to have handy on standby just in case they are needed. The main diff bolts at the rear and front ears are loosened and removed with the hydraulic jack supporting the weight of the diff (it is 90+ lbs so be careful). I don't recall the torque required to reinstall those bolts offhand but it's listed in the TSRM for the SC's and MKIV's-- all the 200mm diffs have the same torque values. The diff is lowered with the support of the jack (a solid block of wood for spacing under the diff can be used). Be slow and careful and ALWAYS keep the diff from wobbling or losing its balance so as to avoid it falling on the ground-- or on you. A trans/diff jack sometimes has metal side guides to avoid this. As the diff is lowered down the axles will drop from the sides of the diff. With the jack fully compressed, roll it and the removed diff out from under the car. Installation is in the reverse order. Again, make sure you use the correct factory torque values for diff installation. A torque wrench you know has good calibration is recommended. Harbor Freight sells $30 digital torque adapters in either 3/8" or 1/2" drive that can be used to roughly test torque wrench calibration accuracy if you're unsure of yours. I believe the side axle hex bolts are supposed to get 64 ft-lbs if memory serves but it has been some time since I looked at the TSRM pages for this. Since you are installing a Supra NA 4.083:1 Torsen LSD (this is often abbreviated to "4.1") into your car which came with a 4.083:1 open diff you will not need to use any aftermarket speedometer recalibrator (such as a YellowBox). In your case your speedometer will read exactly the same as stock. For diff oil it is the same as with your OEM open diff: regular 75W-90 diff oil (such as Mobil1 Synthetic if you prefer) or you can use Redline Heavy ShockProof diff oil. You shouldn't use any special gear oil with a "friction modifier" intended for clutch-pack LSDs. The Torsen doesn't need any special additives and doesn't benefit from them. It's all gear based and the internal Torsen unit itself never requires rebuilding. The factory change interval for open diffs and Torsens is every 30k miles. Other than that, you'll get used to the improved handling and just be aware that once you have a Torsen LSD in these cars you need to be mindful of driving carefully in the rain. Good high performance summer tires with a good rain traction rating and good reviews for wet traction are recommended. Lastly, enjoy! :) Wow thats a lengthy description of how to change a diff. As someone that has done this multiple times here is an alternative version going from memory.
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If anyone here is looking for just the Torsen LSD...PM me, I have one coming available.
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