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| | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | It is not the 8.5" 10 bolt. It is the 9.375" 12 bolt, used from '55-'62. The AJ code may actually be a 3.90, rather than a 3.70. If you're checking from the same source I'm using, there is a typo on the '59 specs, it lists it as a 3.70. Same code for '58 is 3.90, and the shop manula makes no reference to a 3.70 gear. The only options were 3.90, 3.38, and 4.10. There was also a 3.92 gear, but that was the optional Spicer 45 Positraction axle, a one year only option on Chevrolet (was the standard equipment rear, with or without Posi, on GMC).
Bill Burmeister
| | | | | Joined: Sep 2007 Posts: 61 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2007 Posts: 61 | Bill, I am a little confused. There are 10 bolts on the Diff. Cover, not 12...
'59 Apache
'67 Mustang
| | | | | Joined: Apr 2009 Posts: 431 Shop Shark | | Shop Shark Joined: Apr 2009 Posts: 431 | the only way to be sure is to take the cover off and get the numbers off of the edge of the ring | | | | | Joined: Sep 2007 Posts: 61 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2007 Posts: 61 | I need the information because I wanna buy an installation kit (pinion bearings, seals,...). It is really necessary to take the cover off?
Summitracing.com wants to know the size (8.2" or 8.5") and the bolts. Thats it.
@Oilrag
isn't the 235 a 6-banger? I have 16 all in all ;-)
'59 Apache
'67 Mustang
| | | | | Joined: Oct 2003 Posts: 5,152 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Oct 2003 Posts: 5,152 | Summit is probably not the best vendor for something like this. They are oriented to more recent car stuff.
While the number of bolts holding the cover on is a convenient way to identify many GM rears, its not they way they did it back in the 50's.
1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble... | | | | | Joined: Apr 2009 Posts: 431 Shop Shark | | Shop Shark Joined: Apr 2009 Posts: 431 | necessary to take the cover off?
aside from jacking it up and counting revolutions, wheel/ driveshaft, it's the only way to be absolutely sure, bec you don't know what anyone did prior to you owning the vehicle. you don't even know the condition of what's there. what if there are very worn/chipped teeth, or the shims were incorrect and the wear pattern is off? bearings and seals won't cure that | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | You might want to give Patrick's a call. They carry a kit that has all the bearings and seals in it. The cover does throw people off sometimes. While the cover has 10 bolts, the ring gear is 12. Summit does not carry parts for it, nor does Jegs. Also, disregard the limited slip units they list that fit "'62-'76" 12 bolts. They are only good for mid '65-'76. The '62 is the '55-'62 design (like what you have) and the '63- early '65 have a different spline count.
Bill Burmeister
| | | | | Joined: Feb 2000 Posts: 5,194 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 5,194 | Don't you have to pull the cover to work on it?
Clean it out with the cover off and replace the oil, so when you are ready to work on it, it will be some what cleaner.
Last edited by Joe H; 08/16/2009 2:14 AM.
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