I Bought Frankenstein

[2B32]

Over the course of the last couple of years, I have been going through the truck and undoing the weird stuff that has been done to it over the years as needed. This morning I lost my rear U-joint, which poses the next problem.

The truck (cab/frame) is a 71 K20, but based on what I've been told I don't believe the axles are original to the truck. The rear axle is a 12 bolt, 6 lug axle with the following casting and stamp #'s:

Casting #'s GM 53 3896838

Stamp # HB0130W2

Is there any way to find out where this axle came from based on those #'s so I know what U-joint and flange I need?

[geezer#99]

Not sure but might find something here that helps.
http://www.crankshaftcoalition.com/w...identification

[LockDoc]

-
According to the charts I posted here, HB is a 3.07 for '67, '68, and '69 1/2 ton.

http://67-72chevytrucks.com/vboard/s...d.php?t=578793

LockDoc

[wbc409]

If the pieces of the joint are big enough, you can take it to a parts store or driveline shop and they should be able to Mic it a day get you the right one.

[BILT4ME]

When I built my custom 69 K10, I had a 60 transfer case with a GM 12 bolt rear axle. I mic'd the driveshaft U-Joint and the yoke on the rear axle, and searched through the book until I found a cross (U-Joint) that was different dimensions in one axis VS the other.

Then, instead of the standard strap kit used on the corporate rear axles, I had to go with a fully enclosed machined "cap" that installed with Allen head screws. I sheared off two sets of the straps before I went with the caps. I had a 375 HP 350, 4 speed, 33" tires, and 4.10 gears and LS rear differential.

[bean]

Where on the differential is the code stamped? I saw the number that startswith gm but didntsee other.

[zosoppp]

Shouldn't a K20 have had 8-lug axles?

Also if it's a 71 C/K 10 it would have had 5 lugs, 6 lugs ended in 1970 for the 1/2 tons.

['68OrangeSunshine]

Originally Posted by zosoppp

Shouldn't a K20 have had 8-lug axles?

Also if it's a 71 C/K 10 it would have had 5 lugs, 6 lugs ended in 1970 for the 1/2 tons.

Not exactly. And there's no such thing as a ''C/K'' in this vintage. C/K Trucks was some marketing jargon about S/10s later on, but does not pertain to '67-'72s.

K/20=8 Lugs
K/10=6 Lugs
C/10=6 Lugs thru MY '70
C/10=5 Lugs MY '71 on.

2B32: How many lugs on your front axle?. Is it a 4x4?
Could you give us the first 6 or 7 digits of your VIN?

[zosoppp]

my use of C/K was just either C or K not meaning an actual "C/K" (didn't know there was such a thing)

['68OrangeSunshine]

Originally Posted by zosoppp

my use of C/K was just either C or K not meaning an actual "C/K" (didn't know there was such a thing)

Well yeah. Nobody's perfect. But your statement was only correct for C/-class trucks - Post 1971. K/10 [+K/5] trucks retained 6 lugs.