Blew up my rear diff - need rear end ID help - 1970 K10

[34GH111]

So I was going down the road about 40 and BOOM, rear differential decided to start trying to eject metal pieces through the housing.

I'm trying to read posts as fast as I can to figure out what I have and what I need but having trouble identifying...here are some pics.

What rear end do I have?

All I have to go on so far is I've got a 1970 K10 with 3.07 gears,
and this number on the axle TDG0313W
and this number on the carrier 3896839

and this hole in the pumpkin!!!

[34GH111]

Found this great post by LockDoc with axle decodings... based on the axle number I have it appears to confirm that this may be the original axle to the truck? Or at least same year?

http://67-72chevytrucks.com/vboard/s...hlight=3896839

[Stocker]

GM 12-bolt. That's a beautiful truck!

[HO455]

Welcome aboard! Wish it was under better circumstances.

Where are you and that great truck located?

[Ironangel]

GM Truck 12-bolt Positrac, excellent rear end and gear for a daily driver. Hopefully the carrier and posi survived. Those T-12's were used in 1/2 ton C/10's until 81. If you cant find a 12-bolt you can upgrade to a Dana 60 or 14-bolt with factory No Spin or Detroit Locker.

[Accelo]

I own an identical Transmission Jack. Didn't know they made the attachments you have for the differential. Likely handy for transfer-cases also.

If it was me I would replace the assembly. After this stress things are likely bent!
Sounds like this is your goal.
I will qualify this as I have seen amazing repairs with epoxy metal. Mostly when replacement parts were unattainable. If you pull the cover a picture of the carnage would be interesting.

As for the interchange, do the K truck (4x4) have different axle widths like the two wheel drives? Do any of them match the width of the K trucks? Obviously to use one out of the more common 2 wheel drive trucks it would have to be equipped with the rare leaf springs option, if it's a Chevrolet. Or from a GMC where, they all have leaf springs.
Nice truck. Differential only lasted 52 years! Did you put it in four wheel drive and drive it home like I may have. Differential was already dead. Can't hurt it much.
Cheers

[57taskforce]

Originally Posted by Accelo

I own an identical Transmission Jack. Didn't know they made the attachments you have for the differential. Likely handy for transfer-cases also.

If it was me I would replace the assembly. After this stress things are likely bent!
Sounds like this is your goal.
I will qualify this as I have seen amazing repairs with epoxy metal. Mostly when replacement parts were unattainable. If you pull the cover a picture of the carnage would be interesting.

As for the interchange, do the K truck (4x4) have different axle widths like the two wheel drives? Do any of them match the width of the K trucks? Obviously to use one out of the more common 2 wheel drive trucks it would have to be equipped with the rare leaf springs option, if it's a Chevrolet. Or from a GMC where, they all have leaf springs.
Nice truck. Differential only lasted 52 years! Did you put it in four wheel drive and drive it home like I may have. Differential was already dead. Can't hurt it much.
Cheers

Nice carnage!!! GMC’s had coils as an option too. Pretty confident the 67-72 2wd rear won’t work with out more work as the spring perch widths are different between the two. Id find a used housing and swap a new set of gears, and carrier and/or Posi too, if needed and maybe axle bearings and seals if they need it too while you’re there. I realize that’s an expensive list of parts, but in the end you would know exactly what you’ve got as opposed to a swapped in axle of presumably unknown miles/quality of life etc. etc. unfortunately unless you do a re-perch or go to a 8 lug rear axle (sqaure body K30 only 14 bolt FF would be my 1st choice if going this route) than you’ll have to find a 69-72 12 bolt housing to be a direct bolt in. My suggestion would be to look for the last option 69-72 housing and rebuild it before putting it back together.

[Bigdav160]

Now's the time to ditch those 3.08/3.07 pair and put in 3.73 gears

[34GH111]

Thanks for all the help so far...will post pics of the destruction when I have.

I'm in the Fort Lauderdale area. Any suggestions on where to look for a donor rear end? Willing to travel to get it. Or ship.

Yes my preference would be to do a simple direct swap and not modify. I don't mind the expensive list of internal parts - like you said, it would be nice to know for sure what's in there. But having trouble finding the right housing...looking all over on craigslist, FB, etc

So what I'm seeing is I need to find a GM 12 bolt rear from a 69-72 K10 as a 2WD leaf spring axle won't work without modifying mount positions. Is a 4WD GMC 1/2 ton axle also a direct bolt in?

[34GH111]

I'm seeing that the 73 and later K10 axles have a wider spacing on the leaf springs, is that correct?

[franken]

Yes, the frames are the same width, but the frame spring perch brackets are bigger.
As I recall the wheel mounting surface (WMS) (think drum face to drum face) is a bit more making the overall track width a bit larger.
BTW, I think I saw a for sale post for a 70 K10 diff here today.

[34GH111]

Originally Posted by franken

Yes, the frames are the same width, but the frame spring perch brackets are bigger.
As I recall the wheel mounting surface (WMS) (think drum face to drum face) is a bit more making the overall track width a bit larger.
BTW, I think I saw a for sale post for a 70 K10 diff here today.

Thanks - will look back through the parts classifieds and see what I missed. Thought everything I found was old/already sold.

[57taskforce]

Originally Posted by 34GH111

I'm seeing that the 73 and later K10 axles have a wider spacing on the leaf springs, is that correct?

Yep that is correct the only 73-87(91) rear axle that has the correct 67-72 perch spacing of 40.5” on center is from the 77+ K30.

[34GH111]

Originally Posted by 57taskforce

Yep that is correct the only 73-87(91) rear axle that has the correct 67-72 perch spacing of 40.5” on center is from the 77+ K30.

So what about 70-71 blazer axles? Are they a direct swap in for the K10 (leaf and shock perches)? Have a line on one and waiting for some measurements...

[57taskforce]

Awesome! Yep a 69-72 blazer axle should be a direct fit.