: rearend install

01-30-06, 10:10 PM
Anyone know if there be a difference between 1986 fleetwood brougham rearend and a 1979 sedan deville as for as install is concerned? Want to install 1986 into 1979.

01-30-06, 10:15 PM
why would you install a 1986 rear in a 1979?
Second I am not 100 percent but I think they should fit but if you looking for a good rear to put in your car then you should be looking for a 1985 rear because of the gearing ratio it had a tow package. If you gonna change your rear end make sure you get your drive shaft balanced or lightened it helps alot to do either one since you have it out.

01-30-06, 11:28 PM
This 1986 brougham has a 2.73 posi. I was thinking it would be an improvement over the 2.28 if its not to much trouble to install

01-31-06, 12:36 AM
Should be no trouble, but you may need to check on uJoints, as there may be differences.

Do not tow with that rear (do not exceed a 1986 towing spec), else all should be fine.

Be aware, you are likely going from a 8.875" to a 7.5". It is weaker, but don't kid yourself into thinking a 425 can really hurt it. It won't, the 7.5" is still plenty strong unless harshly abused with racing and/or towing.

02-27-06, 11:36 PM
Hello All
I also have access to a 1991 brougham with a 5.7 the 5.7 was an option,also came with 8.5 10 bolt 3.08 gears.My problem is trying to find out if it will bolt into my 1979 sdv with out having to change the control arm brackets,the tread widths are the same 60.7in. anybody know if this is a gm corp.rear end that fits all gm cars from 1977-96

02-28-06, 06:44 PM
It should bolt in just fine.

Dig up NavyLifer on the Impala SS forums, he would know more about it.

But IIRC, doing car-part.com searches showed the 77-96 cars sharing rear ends for most cases. And being GM likely isn't going do too much custom work on a rear for one carline or one year, it should be fine. Get the control arms too.

The 8.5" is the corp 10 bolt, aka "Buffalo" gear, designed by Chevy division back in the late 60's. It was to replace the 8.2" Chevy rear. NOT to be confused with the superior design 8.2 Pontiac rear, which had bolt in axles. The 8.2 Pontiac died off for the 8.5" to the mass market rear end.

The 77-84 or so Fleetwoods had a different rear end, the 8.875" Pontiac "O" axle that was most commonly found with open 2.28's. Strong, but no aftermarket support. I would avoid for performance use only due to no support for it. The 8.5" is pretty tough for most use. Slicks will do it in with enough power, but will survive BB easily, w/o slicks. Once you start hooking up, all bets are off.

The 77-84 "O" axle can also be used, but is exclusive to Fleetwoods. There could possibly be some differences there in u-joints, etc.