Heavy duty differential cover
07-16-2003, 09:37 PM
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Heavy duty differential cover
How do I determine if I have an aftermarket differential cover? Mine has this mark PAT 278 570 on it. The diff has been apart as the shown by the amount of silicone. As well my yokes have caps. I understand that originally in 1974 there were u bolts here. Is this the case?
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07-17-2003, 05:00 AM
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Re: Heavy duty differential cover (Tired74)
I have an aftermkt cover on mine, with the Pat. 279-570 & a 'TFS' marked above it. It has approx. 1/2" thick horizontal spring/x-mbr mounting webs, and approx. 3/8" side suppt. webs. This sucker is HEAVY, in weight that is.
The mounting webs were known to crack on the orig style. (I would assume that the orig covers prob had a 'GM' trademark on it somewhere.) When replaced, it was common to upgrade to a heaver unit. You would see the difference between the two if side-by-side, as the aftermkt units were thicker in the web suppt areas.
Most of the aftermkt units are made of cast iron. The spring mount threads in mine were either stripped out, or about to. I debated about buying a new cover, but figured that with a little time, I'd be back in the same ballpark. So I opted to recoil the threads. At $50 a pop for the recoil kit, and the borrowed odd 19/32" drill size, I figure I'm still ahead of the game. :cool:
As far as your U-bolt caps, these were std on BB cars. SB had the U-bolt config.
[Modified by ROD NOCK, 5:04 AM 7/17/2003]
The mounting webs were known to crack on the orig style. (I would assume that the orig covers prob had a 'GM' trademark on it somewhere.) When replaced, it was common to upgrade to a heaver unit. You would see the difference between the two if side-by-side, as the aftermkt units were thicker in the web suppt areas.
Most of the aftermkt units are made of cast iron. The spring mount threads in mine were either stripped out, or about to. I debated about buying a new cover, but figured that with a little time, I'd be back in the same ballpark. So I opted to recoil the threads. At $50 a pop for the recoil kit, and the borrowed odd 19/32" drill size, I figure I'm still ahead of the game. :cool:
As far as your U-bolt caps, these were std on BB cars. SB had the U-bolt config.
[Modified by ROD NOCK, 5:04 AM 7/17/2003]
