Big Axle/Little Axle?

[itaracer]

I've been shopping for a new rear differential for some time. Till now I thought the whole rear axle assembly was interchangable between all 1985 1st. Gen cars. I knew there was a axle size difference but I thought all '85 diff's were the same. How do I verify the axle size so thsat I get the right Diff?

[tdw6974]

AH The 81-85 axle Puzzle. There is an interesting mixture out there. There is I think in order from 81 to 85. A: Small Axles,with Small bearings and small splines B Small Axles, Large bearings and small splines and C: Large Bearings Large axles and Large splines. Probably Mike at RX-7 Heaven can shed some light Dave at Maztrix any of the 1st gen builders I'm sure can help out.

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Tom Weaver: Logistics & Technical Support Manager IE truck driver for 1980 RX-7 ITA #63
"Hemi haulin' Rotary"

[Scott Nutter]

You need to measure the diameter of the axle at the splines that go into the diff. Then when you talk to whoever you are buying the Diff. from you can make sure your axles will fit. It is properly stated in mm but .001" will probably be ok.

Edit: Brain working faster than the fingers!

[This message has been edited by Scott Nutter (edited May 19, 2004).]

[ddewhurst]

itaracer, there are two different axle diameter rearends. The large axle assembly will measure approx 3 1/4 inches over the outside diameter of the hub behind the banjo flange that the brake caliper assembles to. The same hub on a small axle will measure approx 2 7/8 inches. The axle bearing fits inside these respective hubs. Nothing to take apart. Measure the assembled rearend while it's in the car.

If the axle is out of the rearend the large axle measures approx 1 1/16 inch over the spline.

Have Fun
David