Tech / Tech Articles

Axle ID: A Quick Guide to Identifying Common Rear Axles

Seasoned car guys can often identify cars at first sight.

But how many of us can easily ID a vehicle’s rear axle? It’s a handy skill to have for sure — especially when you’re scouring a junkyard for a replacement axle or evaluating a potential project vehicle. We’ve put together this visual guide to help you hone your rear axle spotting skills.

It’s worth noting that rear axles can sometimes be positively identified by a casting number and date stamped on the differential cover or axle tube. However, road debris, dirt, grime, and general age can obscure these numbers. Fortunately, you can tell a lot about a rear axle by its shape and number of bolts on the differential housing.

Study up on rear axles with this infographic made by OnAllCylinders contributor Lori Sams.





  1. I dont see the Chrysler 8.75

  2. RICHARD H SMITH says:

    Useful stuff! Thanks for sharing Lori!

  3. Gary A. Anderson says:

    Would like to were 57 Pont. is at in your picture

  4. thomas sassin says:

    If You Cant Read The Title. It Says A Quick Guide To COMMON Rear Axles. If You Cant Read And Want To Bitch ,I Couldnt Find The Rolls Or The Jaguar Rear Axle Or The Model T Listed

  5. The 9 inch Fords varied greatly over the years, and they look like the 8s when your sliding in the mud under an old vehicle. Been there,done that.

  6. M. Longoria says:

    Not bitching, but Chrysler 8-3/4 is the most COMMON rearend wanted from us Mopar guys/gals…

  7. RONALD NEWMAN says:

    Thank you for sharing this information with us–I’m sure it will help many street rodders identify what is between them and the road!

  8. Bob Clevenger says:

    8.75″ MoPar is VERY common as millions were made. But it lacks a rear cover, so this page which defines rear axles by their rear cover designs does not apply.

  9. 8″ and 9″ look alike. An easy way to tell an 8″ is if you can get a socket on all the bolts, it’s an 8″. On the 9″, you need a box wrench to get the bottom two. A socket will not fit.

  10. I feel the BOP 8.5″ is a fairly common rear end; LeMans, GTO, Cutlass, 4-4-2, Skylark, GS, all BOP & Caddy full-sizers. Not shown. I won’t complain about not showing the Olds 12-bolt, though.

  11. No D50 either

  12. Pingback: Video: Everything You Need to Know Before Your Ring and Pinion Swap - OnAllCylinders

  13. Dustin Denner says:

    Yea, maybe instead of having just “GM 10-bolt” on the list, you should have “GM 7.5-inch 10-bolt” and “GM 8.5-inch 10-bolt.”

  14. Can you identify a 8.5 gm axle by id nbr? 1285197. It has bolt in axles and is 53 1/4 or 1/2 wide. Thank you for your information

  15. Stuart Saville says:

    Hi I have these numbers stamped on my GM 12 bolt, it’s got 3.07 gears any idea what ages it’s off??

    THS W018 2

  16. Need your help please. I have gm axle “cx0824”. 389914. Nwaww. It has bolt in axles. Can you identify my axle with brand and year? I would like to put in my 1965 chevelle if it will fit.

  17. Need your help please. I have gm axle “cx0824” 389914 Nwaww. It has bolt in axles. Can you identify my axle with brand and year? I would like to put in my 1965 chevelle if it will fit. These identify numbers and letters are they for axle tube. Ring and pinion gear is 2:65 I think it not 100 percent

  18. David Ashley says:

    How can you identify a 373 10 bolt 6 lug rear end 9.5. I know 11-41 is the 373 (GT4). I know to count the bolts on the cover but how do I find out by the numbers if it’s a 9.5 size? G80 is positive traction and possibly a limited slip. I know the locker mechanism and what it looks like but do you identify the size of a 9.5?

  19. David Ashley says:

    It’s for a 1998 Chevy z71 4×4

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