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1998 2500HD 6.5 Detroit TD
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Discussion Starter · #1 ·
Hi all. I drive a 1998 6.5 2500hd with a 14 bolt rear diff with the full floating rear end. Today I was draining the diff fluid and a chunk fell from the diff(see pictures). My most recent issue was that the truck locked as if the brakes were seized right in front of my driveway. I proceeded to check the mobility of the wheels in the front, spun without problems and made no noise. The rear end then had the same thing, easy movement, no strange noises. I rolled the truck backwards and heard awful noises when I stepped in the brakes(which required way more pressure than normal). I had come to the conclusion, after pulling the drums, that the passenger drum brake had a bad MC, cracked shoe and a seized shoe and bad hardware. I figured this was the problem for the lack of movement in the truck as all signs for diff and trans were negative. I then proceeded to change diff fluid while the truck was in the air, and was met with this sheared piece of steel. If anyone has any idea of what it could be from and if my differential is fixable as my new wheels just arrived 馃槴. I appreciate any and all help!
642573

the over-all condition of the differential seems to be relatively ok. The teeth are not sheared or broken. Just your typical metal filings and this little pain in the *ss.
 

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I just guessing it looks like one of the pins that hold the spider gears inside the diff. What I'm talking about is circled in red. Capture.PNG
 
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I'll second that. Nothing else I can think of looks like a cylinder. I'm just amazed at how that would happen. Looks like you avoided serious damage, but it may be hidden, as it kind of looks like ring gear teeth marks on it?

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I believe you could be right. In terms of repairs, what kind of trouble am I looking at?
To be honest I have no idea. Ive never had a 14 bolt ff apart that far. Im sure someone else on here would be able to answer that.
 

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1998 2500HD 6.5 Detroit TD
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Discussion Starter · #6 ·
I'll second that. Nothing else I can think of looks like a cylinder. I'm just amazed at how that would happen. Looks like you avoided serious damage, but it may be hidden, as it kind of looks like ring gear teeth marks on it?

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I think you're right by saying that I avoided serious damage as the diff cover inside is in good condition along with the teeth on the gear. I read that the 14 bolt is over built with these pins. Is this something I should be concerned about? I did previous assessment and the diff seemed to function as it should.
 

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1995 Chevrolet Silverado Z71 6.5 TD
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Looks like the pin sheared off as smdk2500 shows in his pic.
Notice the roughness of the pin in the first pic.
Looks like the pin has been hit or possibly snapped off there then rolled around the rear end for awhile.
I'd pull it down clean and inspect.
 

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1998 2500HD 6.5 Detroit TD
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Discussion Starter · #8 ·
Is it possible that this caused the issue I faced with the truck feeling like the brakes were seized? I drove nearly 20 minutes at highway speed back from work with absolutely 0 problems, n clunking or vibrations in any way, then literally 1鈥 from the end of my driveway, the truck lurched like I stood on the brakes and then hopped into the driveway under decent throttle pressure. My other thought is that this is just an issue I stumbled across but I鈥檓 left curious as to whether it requires my immediate attention or not. Correct me if I鈥檓 wrong but is there a possibility that the remainder of the pin is now permanently in place?
 

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Yes, yes, and yes. I would say the only reasonable course of action is removing the diff and repairing it or replacing it. Don't know what gear ratio you have, but these rear ends aren't that difficult to find and many are still in good shape. Or you could go ahead and upgrade to a locker while you're in there
Either way, you were lucky so far, I wouldn't push it.

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I cannot believe it has not locked up or exploded yet.
14 bolts are sure tough.
 
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1998 2500HD 6.5 Detroit TD
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Discussion Starter · #11 ·
Yes, yes, and yes. I would say the only reasonable course of action is removing the diff and repairing it or replacing it. Don't know what gear ratio you have, but these rear ends aren't that difficult to find and many are still in good shape. Or you could go ahead and upgrade to a locker while you're in there
Either way, you were lucky so far, I wouldn't push it.

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I do believe it鈥檚 the Detroit locker unless the 14 bolt is different?
 

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It's a GM corporate 14 bolt rear end.
If you have G80 on your RPO label then it is a limited slip.
Otherwise it is an open rear end.
RPO label will also indicate gear ratio, if it has not been changed.
 

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I was actually referencing an air locker. I've never actually used or needed one.

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Discussion Starter · #14 ·
It's a GM corporate 14 bolt rear end.
If you have G80 on your RPO label then it is a limited slip.
Otherwise it is an open rear end.
RPO label will also indicate gear ratio, if it has not been changed.
I do have the LSD. I was confused by the statement haha.
 

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Discussion Starter · #15 ·
I was actually referencing an air locker. I've never actually used or needed one.

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I鈥檓 not too familiar with the air locker but the 14 bolt seems easy enough to dismantle and repair. Just a matter of finding the time. Considering it鈥檚 my daily driver, it鈥檚 going to have to become a priority lol.
 

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Unless they changed the design that late that doesn't look like the the stock guts so I'm thinking someone put an aftermarket limited slip in there at some point.
 

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It looks like a stock Gu80 14 bolt FF Gov-lock to me. In need of a rebuild.
 

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Looks like the broken piece has been sitting in there rubbing the back of the ring gear behind the teeth, you can see the wear in the photos. If it was stuck behind the ring gear and couldn't slide around in front of it, that is probably the only thing that prevented a castrophic failure!
 

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Does it look like the pin came out enough to repeatedly strike the inside of the diff case on top just left of the 12 o'clock position? Eventually snapped. Perhaps that's when it felt like brakes. Then, the broken pin fell after being snapped and got chewed up?
 
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