How do I find out if the 91 cummins I just bought came with any kind of limited slip rearend? It's a D250 2-wheel drive

 

Burn out and check the skid marks :-)

 

give your local dealer the vin number

 

Jack the real wheels off the ground ..

spin one ..if the other one goes opposite direction ,you do Not have limited slip
If they both go in the same direction ..you do have

 

I would have told him to do that but it doesnt always work.
I have the factory limited slip and the opposite wheel spins the opposit direction.
I believe most LSD require pinion torque to actuate them in order for this to work. That is unless the LSD is a helicaled geared LSD.

 

The clutch type LSD's do require input from the pinion. Some will and some won't give you the desired effect by turning the tire. The gear driven units act just like a locker and will turn the opposite tire in the same direction if you turn one tire.

After X amount of spins the clutch packs load up and grab the other wheel.......to a point.

I know on my '04 SD that the LS unit let go when it got to about 125 lb/ft of torque difference between the two wheels. So basically, you could call it a limited traction rather than a limited slip.

 

Hook a chain to a tree............. And PuLLLLLLLLLLLLLLLLLLLLL........... Just do not pull the tree down on ya with that Cummins..