Wildcat reardiff

**shw69wldct** · 10-27-2015, 07:28 PM

Looking for Carrier and spider gear along with pinion for my 69 wildcat...43-14....308..9 3/8 ring gear.. ..30 spline carrier....28 spline pinion....or complete rear end....seems to be no after market support!??.

**bob k. mando** · 10-28-2015, 01:05 PM

nope, none beyond bearings.

there are some differences between the 71+ 9-3/8s and 70 and earlier rears. you may still be able to use the gear sets and internals from the 71-76 rears. remember, all of these 9-3/8s rears are Oldsmobile production and are available across the entire GM big car lines. so a rear from a 1970 Olds 98, say, would work fine for you, swapping the whole rear end out or just stealing the parts.

another possibility is to look for a small block B-body ( LeSabre or Impala, for instance ) car from the same model year. the point of this, is that they came equipped with a rear end for the small block engine. ie - 1971-76, a LeSabre had an 8 1/2" ring gear rear end, which would bolt right up to a 71-76 Electra AND also has a gazillion gear sets and differentials available.

the 8.5" rear also offers a performance benefit over the 9 3/8s, as you've got a WHOLE lot less weight swinging around in the back end of the car. otoh, the big rear is almost impossible to kill so long as you keep up on your fluid changes.

i'm not sure if the 1970 small block LeSabres would have 8.5 or 8.2 rears.

**suntreemcanic** · 10-28-2015, 09:07 PM

Would this Oldsmobile family of rear ends also be found under a full size 1972 454 powered police car?

**shw69wldct** · 10-29-2015, 02:30 PM

Appreciate that information about 9 3/8 .....was kind of leaning towards an 8.5, but hoping I can find some 9 3/8 parts or similar axle from an olds...shw69wldct. ...ps..was a member under different e-mail address

**bob k. mando** · 10-29-2015, 09:00 PM

Would this Oldsmobile family of rear ends also be found under a full size 1972 454 powered police car?

all 9 3/8s rear ends are Oldsmobile production. no other GM division made them.

same with the 8 7/8s, except those are all Pontiac production.

8.5" rears were made by all of the GM divisions except Cadillac and there are minor differences between all of them. biggest is that the BOP 8.5s bolted the axles in out on brake housing while Chevy used the C-clips to retain the axles. this means that if you shear a half shaft on a Chevy housing, that wheel assembly is going to go flying off the car, while a BOP rear has a good chance of retaining the axle anyways.

all of the B-body and larger cars ( C, D, E ) should have come with the Olds rear in 72, except for the small block B-bodies which had the 8.5.

in 1973, all of the big cars went to the Pontiac rear. possibly even for small block applications.

**sabrerattler7** · 10-30-2015, 03:32 AM

My understanding was these dif's were in 67-69 Riv's with 430 eng, 225 Electras and Wildcats 68-69 and Estate Wagons 68-69.
Not many posi units, however I found one with 3:08 gears in a 68 Riv, so they weren't just GS options which were generally 3:42.
My dif shop said they couldn't find any listing for parts other than Buick of these years, so I would be very interested if Olds stuff would fit. I have a cage and posi parts with cooked spider gears that I would love to repair. Any sources would be welcome.

**bob k. mando** · 10-30-2015, 01:00 PM

My understanding was these dif's were in 67-69 Riv's with 430 eng, 225 Electras and Wildcats 68-69 and Estate Wagons 68-69

the rears track the different generations of the large body cars.

71-76 is a major generation and 65-70 is the gen before that.

https://en.wikipedia.org/wiki/GM_B_platform
"The GM B-body was introduced in 1926, and had at least 12 major re-engineering and restyling efforts, in 1937, 1939, 1941, 1949, 1954, 1957, 1959, 1961, 1965, 1971, 1977, and 1991"

within a generation, most of the suspension components are going to be the same or largely compatible.

be careful though, as not all full size cars are B-bodies and some of the large variants had some strange geometry. most obvious would be the E-body ( Toronado, Eldorado and Riviera ). the Toro and Eldo have always been FWD ... yes, even with a 500cid. the 63-65 Riv, while RWD, used a track bar for lateral location.

i'm not sure if the 66-70 Riv used a track / Panhard bar or not. if it does, you obviously can't swap the whole housing. but you CAN still use the internals with like year Wildcats, etc.

GM standardized the big car rear geometry from 71-76 as a normal 4 link, so any of those RWD assemblies can be interchanged as full units or, within the same ring gear size, parts wise.

**telriv** · 10-30-2015, 01:34 PM

This 9 3/8ths gear rear was started by Buick in 1936 & modified over the years for the diff. apps. nec. Mostly all the same with MANY changes in between. Then there was sharing with others starting in '71 on Olds & Pontiacs. Rivs. hard a panhard rod until '70 when the four links came out.