Re: 12 bolt rear diff cover
 

Went to order it and it shows out of stock...

Re: 12 bolt rear diff cover
 

Go figure. the part number is: A9070PBK, and when googling that, I found the below one.

Diff Cover

It shows as out of stock as well. You might email or call them to determine when these might be back in stock.

Re: 12 bolt rear diff cover
 

Thank you for that. Looks like they are the same place. I called and he said 4 to 6 weeks. I will keep an eye on it. I don't have to have one right away.

Re: 12 bolt rear diff cover
 

I will keep my eye peeled for a good straight one since your not far from me. I frequent the Springfield craigslist page.

Re: 12 bolt rear diff cover
 

Picked this one up several years ago off ebay. :gmc2:

Re: 12 bolt rear diff cover
 

Z10, that looks good! I saw it on eBay as well for roughly $70.

Re: 12 bolt rear diff cover
 

I mounted my cover on and it fits as it should with no issues. I still need to sandblast and paint it, but I’m happy with the results.

Re: 12 bolt rear diff cover
 

On another note I purchased ARP cover bolts and to my surprise they are too long. At this point I can grind the excess off and true the bolts up with my bench top grinder or stack washers which would be far less time consuming. Not sure if others have ran into this and ARP may make a shorter 12 bolt cover bolt. Sorry in advance for the sideways pictures.

Re: 12 bolt rear diff cover
 

The bolts that come with the aftermarket covers are too long as well. I just re-used my originals.

Re: 12 bolt rear diff cover
 

I purchased washers to use to decrease the length of the bolts, but am unsure if I will use them. I might just reuse my stock bolts.

Re: 12 bolt rear diff cover
 

I did some more digging and the stock rear diff cover bolts are 5/16-18, .50” in length under head, serrated. The ARP bolts for a 12 bolt rear cover are 5/16-18 and .750” long under head, part # 437-3002. A more ideal ARP bolt to use would be the 612-0560 bolt, it is 5/16-18, .560 under head length and after using the washer the bolt is right at .50” in length under the head of the bolt while using the washer.
I know this is nerd bolt info but maybe it will help somebody down the road that is using the stock steel cover. The ARP .750” length bolts might work well with an aluminum cover if it’s a thicker casting.

ARP Bolts

Re: 12 bolt rear diff cover
 

Nice, great info. Thanks for sharing!

Re: 12 bolt rear diff cover
 

Thanks for sharing. Picked up front and rear black differential covers from Assault Racing Products to replace the chrome covers on my 72 Blazer. Less than $12 per cover plus $10 for shipping is a great deal.

https://www.assaultracing.com/item/4...-truck-12-bolt

Re: 12 bolt rear diff cover
 

They are nice pieces for the price! Mine was the same thickness as OEM.

Re: 12 bolt rear diff cover
 

Ahh posting on years old threads... Big Block Chevy/Pontiac oil pan bolts are the perfect bolt for the diff cover. I like to use stud kit on 2x4 trucks that aren't likely to be in rocks and keep bolts on a 4x4.

Canton stainless stud kit on Amazon less than $20. Same with Mr. Gasketbolt kit. And you get 20 of them instead of 10. Two sets will let you do 3 diffs with 4 extra bolts.

Re: 12 bolt rear diff cover
 

The price on Spicer differential bolts surprising ($1.41 ea to 16.99 ea)

An alternative would be nice.

Is this the Mr. Gasket Bolt Kit you are referring to?
https://www.amazon.com/Mr-Gasket-608...1369688&sr=8-7

Re: 12 bolt rear diff cover
 

Yes, that 6086 kit is the big chevy/pontiac kit.

Here is the Moroso version:
https://www.amazon.com/Moroso-38560-...1405271&sr=8-1

The Canton stud kit:
https://www.amazon.com/Canton-Racing...1405285&sr=8-1

Milodon bolt kit:
https://www.amazon.com/Milodon-85005...405430&sr=8-17

Re: 12 bolt rear diff cover
 

Replaced the chrome differential covers front and back with black OE style covers. It looks cleaner in my opinion. Thanks for your help tracking these down for only $35.

Re: 12 bolt rear diff cover
 

Sweet Blazer! I agree that the black cover does look cleaner as well.

Re: 12 bolt rear diff cover
 

Another bolt with a hex head in stainless (less cost)
https://www.boltdepot.com/Product-De...?product=17455
Or even less cost (zinc plated) Grade 5
https://www.ebay.com/itm/25210350877...8AAOSwvx5bYvjN