Rear end question

1964Jet*88 · 07-19-2008, 06:28 PM

Yes I tried to search but couldn't find anything...

I recently picked up an '86 Cutlass with a freshly rebuilt 305. if I take off easy it's fine, if I try to get on it to hard my rear end grinds.

I'll be heading to the local Pull-a-Part next weekend to grab the diff. and a door.

What rearends will bolt up? I'd like a better ratio if possible.
Any G-body should work right? '78-'87? Anything else?

Also what year doors match my '86?

monzaz · 07-21-2008, 02:40 PM

Well you have the diff correct. 1978-1987 ss montes and 1984-1987 GN and 442 came with the bigger 8.5 10 bolt...BUT you will have to also modify the drive shaft length to make that rear fit. If you are lucky to find this 8.5 nder a car...Take the drive shaft too, you will need it.

Ohter than that 7.5 10 bolt is all you get.

Probably the noise is a bearing ...carrier or pinion. see if the pinion is walking in and out the nut likes to unscrew itself if you do alot of pretty good launches.

If not then a carrier or axle bear is probably the culprit. The load will help magnify the bad bearing and or race surface. Like sand on a smooth hard floor. Jim

1964Jet*88 · 07-21-2008, 05:26 PM

I think I found a rear.. 1988 Monte 3.08 Ratio 7.5 $40

Should be all I need with the mild 305. I think I'm going to spend more money making it better handling than fast. As long as it's a decent cruiser with decent power I'm happy.

07-19-2008, 06:28 PM	#1 (permalink)
1964Jet*88 Junior Member Join Date: Jan 2008 Posts: 5	Rear end question Yes I tried to search but couldn't find anything... I recently picked up an '86 Cutlass with a freshly rebuilt 305. if I take off easy it's fine, if I try to get on it to hard my rear end grinds. I'll be heading to the local Pull-a-Part next weekend to grab the diff. and a door. What rearends will bolt up? I'd like a better ratio if possible. Any G-body should work right? '78-'87? Anything else? Also what year doors match my '86?

07-21-2008, 02:40 PM	#2 (permalink)
monzaz Senior Member Join Date: Jul 2006 Location: Richfield, Oh Posts: 108	diff Well you have the diff correct. 1978-1987 ss montes and 1984-1987 GN and 442 came with the bigger 8.5 10 bolt...BUT you will have to also modify the drive shaft length to make that rear fit. If you are lucky to find this 8.5 nder a car...Take the drive shaft too, you will need it. Ohter than that 7.5 10 bolt is all you get. Probably the noise is a bearing ...carrier or pinion. see if the pinion is walking in and out the nut likes to unscrew itself if you do alot of pretty good launches. If not then a carrier or axle bear is probably the culprit. The load will help magnify the bad bearing and or race surface. Like sand on a smooth hard floor. Jim

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07-21-2008, 05:26 PM	#3 (permalink)
1964Jet*88 Junior Member Join Date: Jan 2008 Posts: 5	I think I found a rear.. 1988 Monte 3.08 Ratio 7.5 $40 Should be all I need with the mild 305. I think I'm going to spend more money making it better handling than fast. As long as it's a decent cruiser with decent power I'm happy.