harrisonrick

if its on the car, if I put the car on stands, car in neutral, and ask someone to hold onto one wheel so it doesn't move, how much "play" should there be with moving of the free wheel until it would normally "lock" and cause the other to spin?

OR, if the tranny is on a bench the same would apply by grabbing the hubs that the CVs attach to?

wouldn't this determine if there is a pile of backlash or loose r & p bearings/internals, etc?

the tighter (less play) the better to coin a phrase?

need some guidance here.

thanks!

harrisonrick

anyone?

97xray

Ask Tifo - he's a wealth of information on tranny R & P, I think. (Sorry, Tifo, if you're dodging this one... can't help but point fingers at a true expert.)
-bump-

Mike C.

I'm not sure what to expect when it's on the car because you can't be sure where all of the play is coming from. With tranny off the car you can probably get a better idea if there is a gross problem but the proper way to measure R&P backlash is done with 5th gear removed so you can get a turn the pinion shaft directly. Then you need to buy/make a special tool that allows for measuring backlash with a dial indicator. Here are a few photo links:

http://img217.imageshack.us/img217/5488/p1010031am5.jpg
http://img217.imageshack.us/img217/3985/p1010032ax3.jpg
http://img217.imageshack.us/img217/3811/p1010033yw6.jpg

If it's off the car I would also pull the side cover and do a visual inspection of R&P for any signs of trouble.

tifosiman

Oops, sorry I didn't see this one yesterday~

Mike pretty much nailed it above. I'd also add that a small amount of play is actually normal.

harrisonrick

So...when you'd turn the shaft, how many degrees should there be of play...1/8 turn, 1/4 turn? I refer to the shaft turning itself before the r & p mesh enough to spin the other axle.

Thanks!

Mike C.

The service manual spec is 0.004 - 0.006 thousandths of an inch R&P backlash as measured the way it shows in my photos. If you assume the radius at the measuring point is around 4 inches from ring gear center of rotation, this would equate to roughly 0.07 degrees if I'm doing the math right. In other words, when measured correctly, damn little backlash.... How much beyond the factory spec is OK? Maybe someone who rebuilds them for a living can answer that.