VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Rear End Casting Number

A friend of mine is trying to identify a GM (possibly Chevrolet) 10 bolt rear axle assembly that he has. Here is the casting number on the differential:

GM F82 89812

Can anyone identify this rear axle assembly?

F82 could be the casting date which would be June 8th 1972? On the Passenger axle tube facing the front of the car will be some letters & numbers stamped into the tube. Example would be CBF1023G. Those number might tell the better story...Joe

Nope, F82 isn't the casting date. Found out that F82 indicates that the ring and pinion is a 3.23 gear ratio. Still need to know what the GM 89812 depicts. The above numbers did come from the passenger side axle tube.

You'll need to post more information about the rearend to get closer to what & where it came from.
10 bolt cover?
Leaf spring or coil?
u-joint held in with straps or u-bolts?
5 lug?
Disc or drum brakes
Anything else you can post. In your original post you said they were casting numbers not stamp numbers. GM uses stamp numbers for I.D. purposes...after the assmembly...Joe

Look at the bottom of this page to see if the cover matches any of these
http://www.drivetrain.com/parts_cat...tio_do_i_have_in_my_gm_or_chevrolet.html

From my first post above:

"A friend of mine is trying to identify a GM (possibly Chevrolet) 10 bolt rear axle assembly"

On the other information that you requested, I will get that information and then post it here. Hopefully, that will be of more help to identify the rear axle assembly.

Thanks Joe!

Hey Joe!

Here is the information that you requested regarding the rear axle assembly. Hopefully from the information below you can come up with an application.

Leaf Srings.

U-bolts.

5 Lug.

Drum

The numbers are cast and they are located on the cone housing of the 3rd member, drivers side on the flat part that bolts to the axle housing. There are no numbers on the front side of the axle housings.

All right. I think we're getting somewhere. U'bolt at the U'joint make it 1968 & older. Straps & bolts are 1969 & newer. If it has the original spring mounts they will be pockets. They would've had 2 insulators. Could it have had 1 leaf or several leaves? The only other thing I can think to ask the measurement from outside of drum to outside. Maybe he knows if it has bolt in axles. Ask him one more time to look at the axle tube on the passenger side about 3 or 4 inches from the center section maybe closer to 1 o-clock position instead of 3. Unless it's real rusty it should be there...Joe

Joe:

The springs are mounted on a block. There is no rear cover. The configuration of the rear of the axle housing where a bolted on cover would be appears to be like the second cover from the left on both the top and bottom rows shown on the link above.

The width of the axle cannot be measured since the rear axle is on the car. The stamped numbers on the axle housing on the passenger side are not visible.

Skip
I can only think of one other way to see if it's a GM axle & that would be all the numbers on the edge of the ring gear. If it's GM it will have a part number, a date code & a tooth count for ring & pinion. The other gasket you were looking at was Dana/Spicer....Joe

Hey Joe!

Unfortunately, checking the part number on the ring gear won't work since the rear axle is in the car (it is a driver) and there is no rear cover.

Oh well....at least we tried!

Are you by chance saying this is the old style, drop in pumpkin?...Joe

Don't know because I have never seen it. The rear end is on a street rod and the owner is trying to identify the rear axle assembly so that he will know what he has. All he knows at this point is that the rear axle assembly is a GM unit of some type and that it is possibly Chevrolet. I was able to determine by one of the code numbers that he gave me that the gear ratio is 3.23.

Depending on how old the rod is, it could be one of the tri 5 or one of those 57 Pontiac. If you get more info or pictures let me know...Joe

Okay, will do.

He's going to owe you a beer & me a diet Pepsi if we figure this out...Joe