3 Bolt Rear Swap for a 4 Bolt Rear Question

[BlackHawkAWD91]

I picked me up a 4 bolt rear for a great price. After the fact, I later realized it came from a A/M car. I cant use this rear with a manual car can I? Different final drive cause problems???

Thanks

 

[MackZ24]

Unfortunately No. There are different ratio's in the rear between the M/T and A/T.

 

[sho_pow]

I made the same mistake and blew my Center Diff

 

[twenty5psi]

I would also like some info on a auto to manual swap with the gears in the case..Would this work?..They both run the same case just from the visual aspect..If anything,you can use the axles and buy (good luck finding) a 4 bolt manual pumpkin..

 

[sbiggi]

yes you can just swap the ring gears and pop it back in your 3bolt case.

I did, worked great

One thing though is I had to use the bolts from the 4 bolt diff. The ones from my 3 bolt seemed softer and stretched when I tried to torque them down.

 

[BlackHawkAWD91]

Well the trans is out of the car right now, any easy way to make the change in the trans to make it work with the rear? Thanks for any help.

 

[Goobdog]

What rear gear do a/t's come with ? There should be a sticker on the cover.

 

[BlackHawkAWD91]

Mine says...
Viscous LSD
J1H
3.307

 

[BlackHawkAWD91]

"If someone wanted to change the final drive ratio on an AWD, you need to change the ring gear on the front diff along with the stubby Front Output Shaft that is driven by the center diff. These are both inside the transmission. Then the rear differential ring and pinion gears must be changed to match"

Got that info from vfaq. How hard is it to change those 2 things? Would it be worth it to have longer gears?