Im not looking for what size socket i need. I need to know what size pinion nut i have. I have about 3 pinion nuts now for my 9 bolt and they are all to small. All of them work on 2:77 pinion however will not fit on my 3:91 pinion. I need to know how to figure out what size i have or what size are on normal 3:91 pinions and where to possibly get one fast.
Thanks

 

buy a new one they aren't reuable. go to gm parts or any source of rear end parts and get a new one

 

I understand that however i have been their a couple of times and they keep giving me the same pinion nut which is too small. Is there a difference between a 2:77 pinion nut and a 3:91 pinion nut. Perhaps the danna 44 pinion nut will work.

 

Toxinz:

I assume you are referring to the thread size on your pinion gear. Any "9 Bolt" gearsets we have worked on or sold have a thread size of 0.750" and a thread pitch of 16tpi(threads per inch). The original nuts from the 1985 to 1991 era have a flange behind the hex body, like a Ford nut. However, we have been unable to obtain that style for some time now and have been using the Dana 44/60/70 nut along with the washer Dana specifies to use with this nut. Any GM, Ford, or Chrysler dealers Parts Dept. should be able to supply you with this nut and washer. If not, we have them.

Have a machinist friend check the thread dia and pitch on your pinion before purchasing.

Don