There is a very interesting thread going on about the proper adjustment of a Ring & Pinion gear set. I have a question regarding Backlash. I recently purchased a complete TH differential, which has had new bearings & seals installed, and noticed that there is almost no Backlash at all. (I wish my steering box was as tight as the diff feels). I am concerned that the R & P are set up too tight (it does spin very freely, but hardly any play at all). Are there serious consequences of it being set up too tight?

 

Yes, you can get gear scuffing with no backlash; it squeezes the lube out and the gears rub. Before saying there is no backlash, with dry gears use a dial indicator to measure it. Harbor Freight has magnetic base dial indicators pretty cheap.

Racers used to go with very little backlash but these days don't.

 

When measuring at the perimeter of the ring, with new gears, the minimum is usually in the 0.005" - 0.009" range. Increase a bit for used gears. This assumes that the pinion is rigidly held, nothing is worn excessively, carrier bearings have correct preload, and the gears have been patterned properly.

 

If you are not sure if has been set-up correctly,put some compound on the teeth and rotate the pinion,while putting drag on the ring gear,and see what you get.
You can use lipstick for the compound.