Only when driven for a while and hot my kids 2001 RS has a horrible issue with binding and almost hanging up on a hard turn. CV joint? Low lube fluid someplace? Differential? It's a manual transmission 2-door.

All 4 tires the same size, brand, and tread wear? Properly inflated?

 

The center differential is the cause of the binding. When it gets hot it locks.

 

Mixing and matching tires (2 new and 2 worn) will cause the front and rear output shafts from the center diff to spin at different speeds which heats up the fluid in the diff and makes it lock.

If the problem is left too long it damages the diff and causes it to bind. The only fix is to replace the center diff, but you also need to correct the issue that caused the damage, which is tires. All 4 need to be same brand, style, size, and have even tread wear.

Manual transmissions are far less forgiving then Autos when it comes to torque bind. 

 

How many miles?

 

At this point there isnt much you can do as you need a center diff or transmission.

Tires all brand new Goodyear, matching size. Mileage around 150K. Where is the fluid fill for the center diff? I'll dump a small bottle of GM Limited Slip Diff Additive in it. Works wonders in the new vette tranny's with shifting issues.

It is a sealed unit filled with silicon fluid. Save your money as the fluid never reaches it.

if the car is new to you guys, maybe the prev. owner swapped trans or rear diff and they are different final drive ratios.

The car is an automatic-to-manual conversion but he's had it almost 3 years and this problem only started about 3 or 4 months ago. Biggest question...is it safe to drive? Also, what damage to the vehicle is he doing by continuing to drive it?

Not safe to drive in rain, could be a lot of fun in the dirt. You would be stressing everything from tires, to cv joints, driveshaft and transmission mounts, not to mention the diffs and the transmission itself.

The car is an automatic-to-manual conversion but he's had it almost 3 years and this problem only started about 3 or 4 months ago. Biggest question...is it safe to drive? Also, what damage to the vehicle is he doing by continuing to drive it?

 

Three years and how many miles?

unlikely the final drives are the same (unless internal parts were changed) unless the rear diff was swapped-over from the same car. So, the car has probably been operating under some degree of TB since the swap, and the center diff is now bad.

 

I could be wrong - but that issue needs to be double-checked or you risk performing a repair that will not last.

Wrong FDR would by have caused problems immediately.

 

Binding sresses everything. Axles, ball joints, tie rod ends, struts, front and rear diffs, driveshaft u-joints, everything that makes the car move and steer.

 

Owner of the car the trans came from could have had mismatched tires or driven with tires improperly inflated. Hard to say. Only thing you can do now is replace the center diff.

How do I determine the FDR's on the components?