Bottom of post 2 for info saying that early sc430 diffs are swapable

http://www.supraforums.com/forum/sho...ferential-Info!

unfortunately no info on the gs430 diff.

 

I just swapped a gs400 3.26 diff behind the r154 / GE stock motor. Going to run this for a while the motor is being. In addition, I am running a ORC twin plate clutch, it is super grabby, should make this DD interesting.

 

I run a similar setup.
This transmission and differential gear combination with 295/35/19's in the rear, I'm cruising at 70 mph at about 2400 rpm's...should eek out decent mpg's for those that care about that. For those that are boosted, it gives the turbo room to work in each gear. (1st gear yields about 40 mphs at 6000 rpm's if i remember correctly).

 

I just took it for a drive, I am getting this grinding noise from the diff only when I am accelerating hard in 1st. Hopefully my diff isn't shot, I did change the fluid.

 

I went through the same thing with grinding only under hard first gear acceleration. Had the lsd professionally rebuilt with all new parts other than the lsd itself. Turns out that the 4 bolts that tie the drive shaft to the pumpkin are different lengths. There are 2 bolts that are about 1/2" longer than the other 2. What happens is when under load the drive shaft straightens out and the bolts and nuts were then impacting another part of the car causing the 'grinding' sound. Swapped them around and the problem was gone. The problem is there is no way to see this happening while the car is on a stand, but if you look closely at the nuts and bolts you may see that they are scarred from impact under load. If you see that, swap them around and the problem is solved. Simple fix that I hope solves your problem.

 

SCBlackOut, THANKS! I examined my diff again, the bolts are hitting the subframe. Need to change the bolts out.

 

has anyone ran the numbers for shift points for the stock SC diff/W58 vs Supra Torsen diff/W58? Here is what I get:

(Edit: I am running 255/40-17's on 9" wheels for endurance racing. Measured ground to center for effective diameter)







Here is another thing about the Supra Torsen swap. It is mentioned in most of the threads on here that you may have to change the input yoke. I read that, but when I got my diff I looked at it and said hey, it looks like it is the same as mine. Should have measured, it is only ever so slightly different. When you attempt to bolt it up, the holes are off by maybe 1/2 or 1/3 of a hole. So measure closely before you put the diff in, don't be a dunce like me and get it in then realize it has to be changed. And finding a socket that fits the nut for the yoke, now that was another challenge. I should have wrote down what I used, seems like a 34mm wouldn't fit the nut, I ended up using an SAE socket, but it's been a while back and can't remember exactly.

 

^^ Yes. The Supra MKIV (and GS/Aristo) flanges are different than the SC/Soarer flanges.

The spacing difference should be 101mm (SC/Soarer) vs 111mm (MKIV/GS/Aristo), if I recall correctly.

It's a 35mm deep socket that is needed. I used a Powerbuilt 647079 35mm axle nut socket from Amazon.

To swap the SC socket onto the diff of your choice, it does require using a dial-type torque wrench, not a common click-type torque wrench. You'll want to follow the FSM procedure precisely to make sure the rear pinion isn't over torqued... which could upset the internal gear alignment and shimming made when setting up or rebuilding the differential.

 

It took us 3 rebuilds before we figured that out. After seeing how easy the mistake was to make I was sure that I couldn't be the only one who that would happen to. Glad to have helped out.

 

My my 93 has a welded rear diff and it chews through tires like it's eating bacon I've been through two sets this year but like you said she'll slide everywhere

 

I am running a welded diff in my race car. It doesn't chew through tires like you describe, it just pushes entering turns worse than an open or lsd.