66 Rear Axle #s (Help)

[Wayne M.]

Re: 66 Rear Axle #s (Help)

...The cap-type axles have threads for the hex head bolts that retain the caps. The u-bolt type axles have no threads. The u-bolts are retained by nuts.

Tony -- here's a pic of both styles; the big block with cap(s) is on the right; the U-bolt on the left. In this shot the U-bolt is from a '64-dated rear, and the cap style is off a late '65 diff.



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[Anthony P.]

Re: 66 Rear Axle #s (Help)

Great Pictures Big Help

Thanks Tony

[Anthony P.]

Re: 66 Rear Axle #s (Help)

Ok so I could't wait any longer, pulled the diff unit out today, got the #s off the rear cover Date H-26-5 casting 3871375, going to pull in apart and put in the correct stub flange on the right side since the left has the caps! and new seals, inspect the unit. also I marked the pinnion and axle and it apears to be a 3.08:1, so next question is what should the finish be on the unit and flanges? and are the gears stamped with a date?
Might as well go though the e/brakes at this time just because!!!

[Joe L.]

Re: 66 Rear Axle #s (Help)

Ok so I could't wait any longer, pulled the diff unit out today, got the #s off the rear cover Date H-26-5 casting 3871375, going to pull in apart and put in the correct stub flange on the right side since the left has the caps! and new seals, inspect the unit. also I marked the pinnion and axle and it apears to be a 3.08:1, so next question is what should the finish be on the unit and flanges? and are the gears stamped with a date?
Might as well go though the e/brakes at this time just because!!!

Anthony-----


That's the date on the COVER. What's the casting number and date on the carrier CASE? They will be found on either side of the case.

The ring and pinion gears usually do have dates stamped on them.

[Anthony P.]

Re: 66 Rear Axle #s (Help)

I will check when I get home tonight, how about the finishes paint , natural, or somthing else?

[Wayne M.]

Re: 66 Rear Axle #s (Help)

.... #s off the rear cover Date H-26-5 casting 3871375, going to pull in apart ....... and are the gears stamped with a date? .....

Tony -- that casting date on your rear cover indicates August 26th 1975, IMO, because they weren't dating the '375' rear covers until the '69 model year. (Yes, I know there are those reporting cast dates even on the earlier "303" covers).

If you still have GM gears, they are stamped on the edge, as shown below. The part # and tooth count 10 : 37 is for 3.70 final drive. Also, the pinion is stamped on the end facing the rear cover; you may have to use a flashlight and look beyond the top of the posi case as you rotate the gears to read all the stampings (date, and tooth counts).



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[Anthony P.]

Re: 66 Rear Axle #s (Help)

Wayne Thanks!! I assume the date on the gear is just the month and year?. I bought this car in 1974 and it has just realy sat till now a few occasional rides, cover dates seem odd. I can understand someone braking it in the 8 years before I owned it, will have to see what the gears tell us!

Tony

[Anthony P.]

Re: 66 Rear Axle #s (Help)

Ok just checked the case #s Casting is 3899143, Date is hard to see but might read 1 or I-2-0 ????

[Joe L.]

Re: 66 Rear Axle #s (Help)

Ok just checked the case #s Casting is 3899143, Date is hard to see but might read 1 or I-2-0 ????

Anthony-----


Well, you know it's not original to the car because the 3899143 case was first used for the 1967 model year. Regarding the date, I doubt that the last digit is a "0" because 3 character codes were used for 1970 and your case is apparently stamped "AB", a 2 alpha character code. It might be a "3" or a "5".

[Anthony P.]

Re: 66 Rear Axle #s (Help)

I will try to get pictures of the case date, cover date, and ring gear once I get it apart and post them so I can accuratly determine what it is, and document this portion of the car, and not misrepesent it if I ever choose to sell.