: Rear axle question

Angry Matt
05-18-09, 08:47 PM
I found a 1995ish brougham hearse in the junk yard today. First thing I noticed was the enormous sway bar (almost twice the thickness of a normal one) then saw the monster 14 bolt rear. The brake drums are huge. Does anyone know the difference in the wheels. They were stamped "limo only". I'm wondering if I go back to get the rear, are my wheels going to fit over the drums? Also, being a newer brougham, is there traction control that's going to give me problems? It would be going in my '81. I'm assuming it's a 3.08. That seems to be the standard commercial ratio, but no limited slip tag. How can I tell? Any info is appreciated.

05-18-09, 09:50 PM
The rear in your 81 is the 8.875". Very strong, and the 9.5" one from the hearse won't be much of an upgrade. It is a truck axle.

The 14 bolt rear didn't get traction control or ABS, so you don't have to worry about that.

Wheels "should" fit. Won't know for sure until you try. Best thing to do is bring one of yours to the yard.

To find out the axle ratio: find the SPID sticker and look for the "G" codes. G80 is posi. Here are the codes:

9.5" w/o ABS / HD disc/drum RPO J55 brakes

4ME / 2.93 (GW9)

2MP / 3.42 (GU6) w/locking axle'

If you can't find the SPID, turn the wheel one time completely and count the driveshaft revolutions after making a mark. This will tell you the ratio.

06-07-09, 09:11 PM
I'm going to look at a parts 91 350 soon and was wondering how you tell the difference in the rear axle. I guess theres a code on the axle itself but is that the only way to know. Is there a code on the truck lid?

06-07-09, 09:16 PM
Yes, just write down the codes that start with G. From my example above: GW9 is 2.93. Also, G80 is posi.

Angry Matt
06-07-09, 10:44 PM
If I remember correctly the code was GM7 on the hearse. It's still there and for $50 it's hard to pass up. I recently swapped mine for a 3.23, but it's an open rear. That's the only part that bothers me. I just hate knowing there's something better that's easily within my reach. I think though the 14 bolt might be overkill? And if you're telling me that it's either a 2.93 open, or a 3.42 posi, I would take neither. I'm gassing up every time I leave the driveway now.

06-08-09, 05:38 PM
GM7=3.68:1 open

06-12-09, 03:42 AM
it says GU4. Is that like a 3.04/3.07...? It was a ten bolt

06-12-09, 12:07 PM
GU4=3.08:1 open

06-12-09, 10:49 PM
GU4=3.08:1 open

GU4 doesn't tell you if it is open or not. If there is no G80, it is non-posi.

06-12-09, 11:15 PM
There was no G80 code. I still need it because mine is whining, but I might be getting another parts car with the tow package. If it was a 3.73, would it still bolt right up. Jay, you once said something about machining the yoke or something like that, does that apply if changing from a 3.08 to the 3.73 from the same year
(90) car. I'll be keeping the 200r.