Rearend I.D. help?????
 

So I bought this toy about three years ago.
It's a 66 Chevy short wide 4x4 with a small block 400 and an automatic.
After raggin the hell out of it, metal worms have finally made me tear it down to rebuild. (the cab floors were gone and the cab was settling)
I am trying to figure out what the rearend came out of.
It is NOT stock to this truck.
It is a GM 12 bolt, mounted on a ridiculous 7 leaf high arch spring pack. The spring perches have been remounted I am assuming to correct the pinion angle. (It also has 4" lift blocks.)
They have also been moved outboard one inch on both sides.
The previous owner (who did not build the truck) told me when I bought it the running gear was out of a '77 blazer. The frame numbers are from a '66.
I have searched on the web but can't find anything definitive.

So... anyone "in the know" who can help me verify what it came out of , I would really appreciate it... or maybe you could point me in the direction of where I could find it.

3896839 N -- casting number on the housing
E 4 7 -- date code on the housing
KAH 126W71 -- axle code on the passenger tube

Don't know what the gear ratio is as I have never had the cover off of it.
If anyone could help??????
Also forgot to mention the axles are standard chev 6 lug.

Re: Rearend I.D. help?????
 

:eek: WOW!!!! Nobody?????

Here's one for a giggle: In desperation I called the local GM dealer and talked to their parts guy. Gave him the info I posted above. Told him it was a 12 bolt with 6 lug axles. Told him I thought 70's era.
He said he didn't have a book that listed those numbers and he would have to call GM and would get back to me.
Called back about thirty minutes later and told me " your differential is a 10.5" ring gear 3.73 ratio rearend out of an 81 to 90 one ton truck or an
81 to 93 panel."
Hey..... I"m not a rocket scientist but "BULL****"
There is NO WAY this thing has a 10.5" ring gear. It would have to be a 14 bolt.
I can count.
I am going to crack it open when I get back to the shop and see if I can get some numbers off the ring gear.

Re: Rearend I.D. help?????
 

They were available a lot of years. I have a 72 with a 12bolt... as far as i know, a 12 bolt is a 12 bolt.. they were available in car and light truck applications. If you know its not original, then what more do you need to know?

Re: Rearend I.D. help?????
 

12 bolt truck diffs are different than 12 bolt car diffs. car 12 bolt had a larger pinion gear shaft diameter, different carrier, different cover etc.....with your date code 77 blazer sounds feasible. pics?

Re: Rearend I.D. help?????
 

Eturnit3- perhaps you could go to your nearest Oreillys or Autozone or whatever and tell them you need brake shoes ... or an axle seal.
Guess what they are gonna ask you? That is exactly the "what more" I need to know. Right now... I can't tell them its a 66... or its a 77... or anything... follow me?
I don't relish the idea of pulling a shoe off of it and looking like a moron telling them "I need a new one of these, its off a chevy 12 bolt."

Clinebarger -I am going to pull the cover first thing in the a.m. and try to get a date from the ring gear. I will snap a couple close-up pics and post them.

Re: Rearend I.D. help?????
 

If you bring in the shoes, the match them some how, i did it with mine, and with the wheel clyinders.

But, i would pull the cover and check the date there.

Re: Rearend I.D. help?????
 

If your worried about looking like a fool in front of a part store jockey, Dont be! all they know is to type s#it into a computer and look like a deer in the headlights.
up till 72 they used 11x2" brakes no cooling fins on the drums. most 4WD stuff of a later model has been 11x2 3/4" with cooling fins. So drum diameter & shoe width whould help narrow down the year

Re: Rearend I.D. help?????
 

don't have a close up on the rearend yet but here is the few shots I have of the teardown so far. Will post more tomorrow.

http://s676.photobucket.com/albums/v...gedEdge_album/

Re: Rearend I.D. help?????
 

OK... got the rear opened and got some more pics.

http://s676.photobucket.com/albums/v...gedEdge_album/

The gearset reads : 3817779 14 43 GM 2 71 1

and clinebarger... lol... no... I am not worried about looking like a fool in front of the counter guy at the local parts house. Exactly the opposite.. I went in for an outboard axle seal for my 89 chev 4x4 and after receiving the wrong seal TWICE I pulled the old one and took it down there.
Guy tells me its from an 89 chevy K1500. Well duhhh you asshat. I told you that both previous times.
I have really bad luck with parts people. Main reason I am looking for this info is so I can order online. Maybe I can break the mojo.

Re: Rearend I.D. help?????
 

KAH 126W71---1971 4WD Suburban Carryall---might explain the rediculously high arch springs with that number of leaves.

Re: Rearend I.D. help?????
 

:metal: BINGO!!!!!!
WE have a winner!!!! I will go with that.:c2:
That explains a LOT. The engine, trans, transfer, gearset all code to a 71.
What is weird is.... the frame numbers match the cab and code to a 66. A two wheel drive 66.Also
the date code on the rearend housing is clearly E47. And it has the finned brake drums but only two inch width shoes.
Now...... give it up.... WHERE did you find that info???????:banghead:

Man you DON'T KNOW how much I appreciate this!!! Being an anal OCD type it was driving me crazy not knowing.

THANK YOU!!!!

Re: Rearend I.D. help?????
 

The numbers came from Chevrolet Truck Chassis Service Manual for C-K trucks 1967-1971
it's out of print but if you search American Classic truck parts they sometimes have used copies in good condition. They also have a an online VIN decoder and one of your numbers is a partial VIN... which agrees with my manual. http://www.americanclassic.com
These guys saved my backside when I started my 67 stepside...same problem you have. Some gomer pulled it out of a field in Texas and proceeded to cobble together a truck out of whatever bits he could find. To fix it I had to ID all of that stuff he did. The only thing that matched was cab and Frame.

Re: Rearend I.D. help?????
 

Excellent!!!! I will check and see if I can find the manual you have. Maybe on Eplay.
Again... THANK YOU!!!
I think its exactly what you described... a collection of leftovers.
I am gonna continue with the rebuild, and may call on ya again if I hit a snag.