How much free play should be in a limited slip rear end? Mine is starting to make a noise when I take off, like a thump. I looked at my drive shaft and it has some play when I crank it back and forth with my hands.

 

Total Backlash Check

1. Raise and support the vehicle.
2. Remove the driveshaft.

3. You will need to fab up a tool to bolt to the pinion flange. Clamp a rigid bar or pipe to the tool. Clamp the other end of the bar or pipe to the frame or a body member in order to prevent movement of the pinion flange.

4. Lower the vehicle so that one rear wheel is resting on a wheel chock to prevent it from turning. The other rear wheel will be used to measure total rear axle backlash.

5. Rotate the free wheel slowly, by hand, until the feeling of driving the rear axle is encountered. Place a mark on the side of the tire, 305 mm (12 inches) from the center of the wheel, with a crayon or chalk.

6. While holding the crayon or chalk against the tire, rotate the wheel slowly in the opposite direction until the feeling of driving the rear axle is encountered again.

7. Measure the length of the crayon or chalk mark on the tire.

lIf the length of the mark is 25.4 mm (1 inch) or less, the rear axle backlash is within allowable limits.


JMC

 

Is the play in the U-Joints or are you sure its in the diff? I would start there first, they usually go out before the diff.

 

That's a hell-of-a way to measure backlash. I have seen many 8.8's with the case worn out and allowing the cross pin to wobble. I believe this would multiply the backlash at the wheel due to the spider gears having excessive movement. This is not a good/correct way to measure backlash.

 

That's a way given in some repair manuals to get a rough idea of backlash. If you have little play OK. If a lot well it needs the dail indicator on a tooth etc.