Help of a 07 chev front diff, losse bolts torque specs?

[Alan]

I have an 2007 silverado 3500 fwd. noticed an oil leak a few weeks ago, could tell from the smell it was differential fluid. Pulled the skid plate and most of the bolts connecting the axle housing to the differential were loose. I tighten them all but within a week it had started leaking oil again, some were loose, gave them a little more muscle this time but didn't want break anything. A couple of weeks later a "little" loose agian and a little oil leakage.

I can't find a torque spec, have not asked chev service dept yet. Any ideas? Just a matter of torque or more like a gasket replacement? Any thoughts?

I have attached a photo off the net, the bolts I'm referring to appear to be pink in the pic.

Thanks,
Alan

http://www.google.com/search?q=2007+sil ... H4b85SM%3A

 

[Alan]

At least on my iPad, when I hit the link it goes to my google search and then goes to the pic in a few seconds.

 

[BryanM]

first what size diff 8.25 or 9.25? are you talking about the five bolts attaching the right axle tube to the case? another thing are you re sealing or just tightening the bolts?

 

[Alan]

first what size diff 8.25 or 9.25? are you talking about the five bolts attaching the right axle tube to the case? another thing are you re sealing or just tightening the bolts?

Thanks for the response Bryan, I'll see if I can determine the size of the diff. If it helps at all, my truck is an 07 silverado, 3500 HD, Duramax with the Allison trans. I have not sealed the bolts, just tighten them without torque specs.

Thanks again, hope this helps.

Alan

 

[BryanM]

alan if its the five bolts that you are talking about the torque spec for 9.25 ring {which I bet you have} is 30lbs. there is sealant in between the case and tube that seals it. I have never seen these bolts come loose tho. I myself would probably put a drop of locktite on them. Just a drop and blue (medium) locktite. also make sure your breather tube is clean, I have seen a blocked or kinked tube cause leaks but never cause loose bolts.

 

[Anonymous]

I'll second the blue loctite. But remove the bolts one at a time and clean them first with some brake cleaner.

 

[Alan]

Thank you very much Bryan an hook! That's exactly what I'll do is a little lock tight on the bolts and torqued down.

Again thanks to both of you!

:tiphat:

Alan

 

[Kscattle]

A caterpillar mechanic told me a couple months ago that bolt manufacturers are designing bolts with a "one time use" theory. He changed wheels on a new cat loader and threw the old bolts away saying these new bolts once torqued will stretch to certain specs, and if loosened they need to be discarded since they can't be "stretched" again and they will come loose. I don't know about your application but you may need to ask the dealer.

 

[BryanM]

those are called torque to yield bolts, and yes theyare being used more often but usually head bolts, camshaft bolts, crank bolts etc.. Does not apply in this situation. a spec say on a head bolt would be 44ftlbs + 90degrees+90degrees