3rd gen rear end install in 4th?

**transamjeff17** · 04-22-2009, 07:38 PM

Hello everyone! This is my frist time making a "real" post on this site. I do have to say this site is awesome and is full of very useful information!
Here is my situation, i have a 2001 ws6 auto. For the past 20,000 or so miles i can hear a whine coming from the rear end of the car and i feel that its not going to last much longer. I have advailable to me a rear end out of a 89 trans am 305 (auto) that is free. Im curious, will they be compatiable? I wont have any problem ripping out the old one although if things dont fit when i put the 3rd gen rear end in, then i will have a problem lol. Just want some advise before i continue. I dont know anymore information on the rear end of the 3rd gen other than it is a 10bolt also. If it isnt worth it, then sugesstions as to where i can order one from online.(complete bolt up)
Thanks!
Jeff

**thearborbarber** · 04-22-2009, 08:10 PM

I got a rear with 50000 miles from these folks

http://motors.shop.ebay.com/merchant/pick_a_part?_rdc=1

**teamgotoil** · 04-22-2009, 08:25 PM

This is too funny. I just posted the same question on LSXNation a week or two ago. Got some answers from there. Most said it will fit, but it is a little shorter. Requiring wheel spacers. I have yet to try it, but I should be trying it in the next couple of weeks. I will post end results on here. Good luck.

**Redphoenix1998** · 04-22-2009, 09:30 PM

you will need spacers and depending on the rear, you could lose your rear ABS or TCS

**big hammer** · 04-23-2009, 04:37 AM

Originally Posted by transamjeff17

Hello everyone! This is my frist time making a "real" post on this site. I do have to say this site is awesome and is full of very useful information!
Here is my situation, i have a 2001 ws6 auto. For the past 20,000 or so miles i can hear a whine coming from the rear end of the car and i feel that its not going to last much longer. I have advailable to me a rear end out of a 89 trans am 305 (auto) that is free. Im curious, will they be compatiable? I wont have any problem ripping out the old one although if things dont fit when i put the 3rd gen rear end in, then i will have a problem lol. Just want some advise before i continue. I dont know anymore information on the rear end of the 3rd gen other than it is a 10bolt also. If it isnt worth it, then sugesstions as to where i can order one from online.(complete bolt up)
Thanks!
Jeff

dude a complete bearing kit is around $100, plus another $200 for new gears if it needs it. just rebuild the one you have! i find it's actually easier then swapping out a complete diff, especially when you gotta start modifying stuff.

**teamgotoil** · 04-23-2009, 04:41 AM

I am sorry. I forgot to mention...my 4th gen is a drum brake rearend and the 3rd gen is a disc rearend. That could be some of the problem with it being a little more narrow.

**bigrondownhiller** · 04-23-2009, 02:16 PM

Originally Posted by big hammer

dude a complete bearing kit is around $100, plus another $200 for new gears if it needs it. just rebuild the one you have! i find it's actually easier then swapping out a complete diff, especially when you gotta start modifying stuff.

That is what I would do. The third gen is narrower than a 4th. Your wheels will stick out. The third gen could also have drums which would have to be switched to your brakes to work properly. If you want to upgrade a 12 bolt or 9" would be the way to go.