Are my gears toast?

[TheFleshRocket]

I've been noticing a clunking noise from the rear end of my '89 Mustang. I assumed it was a U-joint going out, but I checked them out and they seem to be tight. The clunk is coming from inside the pumpkin. When I twist the driveshaft by hand, it moves about 1/4 of an inch before I hear a clunk and then the drive wheels start to turn.

So it seems that there is too much clearance between the ring and pinion gears. My question is whether or not there is anything inside the pumpkin that can be adjusted to tighten up that clearance, or if my gears are just worn and need to be replaced. What do you guys think?

The car has just under 80K miles on it, but the 3.27 gears I've got right now I bought used (probably a mistake--the next set will be brand new) and had them professionally installed about a year ago. I'm seriously thinking about going with 3.73s instead because the 3.27s are just too damn tall.

 

[meze1111]

All things point to yes IMOAnd yes go 3.73. And m ake sure someone that knwos what there doing installs.

 

[89MustangGX]

I still lean towards the u-joints unless you took the driveshaft out and checked things. The ds has a way of transmitting sound and making it sound like it might be insude the rear when it's not. Besides -- you're better off taking the ds out to check the u-joints anyway, and they're much easier/cheaper to replace than going inside the rear.