i just took a posi disc rear end off a 87 pontaic trans am. On the bottom of rear end, it has a part number. K8J5 then says borg wagner. what rear end is this???? what gears are in it??? please get back to me asap. How do i find out what gears i have.

 

It's a 9 bolt. Unless you know a lot of info about the donor car your best bet is probaly to count the teeth.

 

are u sure it isnt a 10 bolt???? thats what i was told it was

 

Count the bolts on the cover.

 

ok i am an idiot. why did i ask you that when i can just go upstairs into garage and check the bolts myself. your right, it is a 9 bolt. I guess they are from australia and parts for these rear ends are rare and when found - expensive. it is a 7 3/4 9 bolt. all these rear ends with disc brakes from factory are 9 bolts. but the thing is - i have a 10 bolt rear end that blew and that is also a rear disc. I guess that someone did a swap b4 i got car. How do i figure out what gears i have in there??? what do i count??? im new to this so bear with me.

 

Divide the number of teeth on the ring by the number of teeth on the pinion and that is your axle ratio.

 

9 bolts it's borg warner.borg warner has 3 gear:2.77, 3.23, 3.45,with the 5.7 l gm more often uses a 3.23 gear end.martin

 

a little fact is all 305 tpi 5speeds got the 3.45. all others were standard 2.77 but the option was available for a 3.23

 

yes, but the 350 the gear end is 3.23 and the 305 is 2.77,me I ever saw of 2.77 on one 350,if that exists, that must be very rare?martin

 

my 350 has the 2.77's my friends 350 has the 3.27's

 

ok i'm soory,me I ever saw.