Differential Cover Bolts

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Kevan

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Hey folks. I noticed that my differential cover bolts have started to turn that lovely shade of orange and would like to replace them before that 'orange' begins to spread. (I don't want to say the "R" word) Plus, it looks like crap.

Does anyone know the size, thread/pitch, torque amount?
Or where I can score a nice stainless steel set?

Also, will I have to re-seal/re-gasket the cover if I just replace one bolt at a time?
 
You might try doing a search, someone just replaced theirs in the last few days. You will not have to worry about resealing the cover if you do one bolt at a time. There's a link posted in the last day or so for the service manual, it will have the torque settings in it. If you do search and can't find what you need and no one posts up the info, let me know and I'll find it all for you...
 
Kevan, bro, how ya doin? What I would suggest it to call ARP for a set. They do not list a set for the Dana, but they do list sets for the Chevy 12-bolt. Probably the same, but I would ask first. Their tech line is 1-800-826-3045, call 7:30-4:30 Pacific Time. Their website is www.arp-bolts.com. Part # for chevt 12-bolt is 437-3002. I would remove one of the top bolts from your cover and check the size, length and thread count before calling them. Then, they would be able to set you up with the right set without a doubt. You should be able to pull the bolts out one at a time without disturbing the seal of the original gasket. Don't forget to put some blue RTV on the new bolts before replacing, and torque to spec before working on the next one. Hope this helps.

Greg
 
Mine too!

Let us know how you resolve this issue...thanks.
 
Awesome Silver! Thanks!
I thought I'd read something on it, but couldn't remember if it was here or the 'other' forum.

JEGS link:
LINK REMOVED
$20. Not bad.
Thankfully JEGS is local and open on Sunday, so I'm going to stop over today in this oppressive heat and pick up a set, then work on the truck in the sauna....ahem...I mean the garage. :)

I'm still sifting through the 05 manual. There are only 8400+ pages.
:D

Torque specs for the diff. cover are on page 558 of the manual:
"Install cover and tighten bolts in criss-cross pattern to 48 N-m (35 ft. lbs.)"

Before and after pics will be posted soon.
 
Last edited:
Well, so much for a quick Sunday project.

The bolts that JEGS has are INCORRECT!!!

  • JEGS bolt package (P/N #070-437-3002): 5/16-18; 1.0" length.
    [*]SRT-10 Rear End Cover Bolts: 3/8-16; .75" length flange bolts.
The guy at JEGS tried to tell me they were Metric.
I'm not sure why I took his advice after that, but I did. I tried a local Sears Hardware store. No dice.

Tomorrow I will check with my local Fastenal store and another great bolt store I frequent.

Updates to come.
 
Ace Hardware - stainless hex head bolts 3/8X16X 3/4" with stainless flat washers $6.50 for all 20 items!

john
 
Thanks John, but I was trying to do it as a 1 pc. flange bolt and not with a separate washer.

I'll keep looking.
 
Ok, who's ready for some updates with pics? :)

Tip: Remove the spare tire from under the truck before doing the diff. cover bolts. It makes it SSSSSOOOOOOO much easier (and roomy!).

Here's what the cover bolts look like now (7100 miles on the truck):
http://tremol-no.com/images/woodblock/srt10reardiff/P1010180.JPG

Apparently, 3/4" 3/8-16 stainless flange bolts are EXTREMELY rare. After 9 different stops in the last 2 days as well as thorough searches on both McMaster and MSC, I found that Fastenal could order them....but....the flange has a serrated face.
This is very bizzarre to me. I would think that this size and thread would be VERY, VERY, VERY common and desired.

Maybe I'm way off base.

I went to the main JEGS store today, original bolt in hand. They do have an ARP set that will fit:
Part# 070-400-1102
They are header bolts for a BB Chevy engine.

Installed on the rear end, they look like this:
http://tremol-no.com/images/woodblock/srt10reardiff/P1010001.JPG
Looks fine, right? Well, get a little closer....
http://tremol-no.com/images/woodblock/srt10reardiff/P1010002.JPG
The flange on the bolt itself is a joke. The washer is not centered, and doesn't even come close to the old bolt regarding coverage.
The ARP bolts will be returned tomorrow.

I'm considering having the original bolts powder-coated, along with a few other items. Maybe Viper red? :)
 
Thanks Kalani!

I'll check into Penetrol (the US distributor is only about 2 hrs. away. That'd be a nice drive...heh heh).

It looks as though it's a thick/paint-type liquid. How did you spray it on or apply it?

I'd love to see the pics. Thanks!
 
Kevan said:
Thanks Kalani!

I'll check into Penetrol (the US distributor is only about 2 hrs. away. That'd be a nice drive...heh heh).

It looks as though it's a thick/paint-type liquid. How did you spray it on or apply it?

I'd love to see the pics. Thanks!
Click to expand...

I bought it in a spray can - i used 3 over 2 days (took my time) and slowly went around rust converting the bad spots and then spraying the nuts/fram rails/diff housing and really anything i thought would rust. It looks brand new as it dries to a clear film with a slight shine.

I got a bit lazy in the end and just sprayed it straight over some rusty bits but then once it dried i covered it with an underbody rust/tar spray - look at the link. I also used this on the seems and anything i wanted to cover up.

Ill post some pics on monday for you.

http://www.septone.com.au/detail.asp?item_cat=5&item_number=205&page_num=2

If you want - i could send you some - might be cheaper than the 2 hr drive?
 
Kevan said:
Ok, who's ready for some updates with pics? :)

Tip: Remove the spare tire from under the truck before doing the diff. cover bolts. It makes it SSSSSOOOOOOO much easier (and roomy!).

Here's what the cover bolts look like now (7100 miles on the truck):
http://tremol-no.com/images/woodblock/srt10reardiff/P1010180.JPG

Apparently, 3/4" 3/8-16 stainless flange bolts are EXTREMELY rare. After 9 different stops in the last 2 days as well as thorough searches on both McMaster and MSC, I found that Fastenal could order them....but....the flange has a serrated face.
This is very bizzarre to me. I would think that this size and thread would be VERY, VERY, VERY common and desired.

Maybe I'm way off base.

I went to the main JEGS store today, original bolt in hand. They do have an ARP set that will fit:
Part# 070-400-1102
They are header bolts for a BB Chevy engine.

Installed on the rear end, they look like this:
http://tremol-no.com/images/woodblock/srt10reardiff/P1010001.JPG
Looks fine, right? Well, get a little closer....
http://tremol-no.com/images/woodblock/srt10reardiff/P1010002.JPG
The flange on the bolt itself is a joke. The washer is not centered, and doesn't even come close to the old bolt regarding coverage.
The ARP bolts will be returned tomorrow.

I'm considering having the original bolts powder-coated, along with a few other items. Maybe Viper red? :)
Click to expand...

Look in the yellow pages and find a bolt retailer, they'll have polished stainless bolts. You're looking for a very common size, it should not be an issue. Worst case is you'll need to ue a washer under the bolt. I understand you're trying to use a one piece but at some point you have to give up if you can't find them.
 
Texas Yellow Fever said:
Look in the yellow pages and find a bolt retailer, they'll have polished stainless bolts. You're looking for a very common size, it should not be an issue. Worst case is you'll need to ue a washer under the bolt. I understand you're trying to use a one piece but at some point you have to give up if you can't find them.
Click to expand...
Oh, I know how common the size is. The only size more common is 1/4-20. :)

I did use the yellow pages (and the 'net) and contacted or researched 9 different bolt suppliers. None had any in stock, but Fastenal could order them for me. The only difference is that these flange bolts have a serrated face. The serrations are minor and should not impact the housing all that much. Plus, they provide a little bit of re-assurance, and that's fine with me.

I also know about the misconception that stainless steel is stronger than carbon steel. The bolts on the differential cover aren't load bearing (just pressure bearing), so overall strength and shear rating isn't a major factor. Stainless should be more than enough to handle the duties.

I picked up the bolts today. They look great and will be installed (with pics) as soon as the temp in the garage drops below 110F.

3/8-16 Stainless Steel Flange Bolt Info
  • Company: Fastenal (Columbus, OH) 614.221.4300
  • Contact: Matt York
  • Part Number: 11443-00382
  • Price: $1.50 ea

With tax and shipping, I paid $20.04 for the 10 bolts.
 
Kevan said:
I also know about the misconception that stainless steel is stronger than carbon steel. The bolts on the differential cover aren't load bearing (just pressure bearing), so overall strength and shear rating isn't a major factor. Stainless should be more than enough to handle the duties.
Click to expand...

The load bearing part may not be true. I don't know if you have a QC or RC. On the RC's the top of the differental cover is also the attach point for the torque shock that runs to the frame. That means that the cover bolts are seeing a higher tension load than standard cover bolts.

With this being said, the torque value is more important than normal. I would also recomment against using serrated head flange bolts. They will screw up the torque readings.

For those with a QC, you can ignore what I said. Or you can just ignore what I said anyway. Just wanted to make members aware of what is happening.
 
Damn. I hate when Silverback is right. LOL I forgot about that linear shock mount. Damndamn.

I just checked the specs on carbon vs. stainless for 3/8-16 bolts.
  • Carbon= about 120,000 to 150,000 psi. tensile strength.
  • S/S= from 80,000 to 115,000 psi. tensile strength.

Not exactly equal, but also not that far off. I think the S/S will hold that differential cover on just fine, even with the added force from the linear shock.

I think it'd be easy to compensate the torque for the serrations, no?

I'm going to try to email the folks at DANA and find out more info.


As much as I enjoy learning (esp. about the trucks), this is all of a sudden far too complicated. Next time, I'm gonna break out the BBQ paint and do it 'trailer park' style.
 
Silverback said:
The load bearing part may not be true. I don't know if you have a QC or RC. On the RC's the top of the differental cover is also the attach point for the torque shock that runs to the frame. That means that the cover bolts are seeing a higher tension load than standard cover bolts.

With this being said, the torque value is more important than normal. I would also recomment against using serrated head flange bolts. They will screw up the torque readings.

For those with a QC, you can ignore what I said. Or you can just ignore what I said anyway. Just wanted to make members aware of what is happening.
Click to expand...
Did you say somethin?:D

Bill.
 
WARNING!
It is next to impossible to get any sort of tech support from DANA. I went thru half a dozen menus, then several menu options, only to have the tech tell me that he couldn't find the rear end specs. When I asked about the bolts he flatly said, "We don't recommend changing any of the bolts."
Sounded like my dad.

The serrations on the flange are uni-directional (preventing loosening). That should not affect the ability to properly torque the bolts.
 
Texas Yellow Fever said:
Look in the yellow pages and find a bolt retailer, they'll have polished stainless bolts. You're looking for a very common size, it should not be an issue. Worst case is you'll need to ue a washer under the bolt. I understand you're trying to use a one piece but at some point you have to give up if you can't find them.
Click to expand...
I agree, if you feel that the colts may become loose, use a lock washer or some thread locker on the bolt. In my experiences I have never seen loose differential cover bolts, and people would use about any kind of bolt on the cover as well. :(
 
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