6 lug 12 bolt

[Old Radio Tech]

On the GM 12 Bolt truck rear end used in 1960-66 trucks, was 6 lug or 5 lug standard?

[Ken Cook]

My 63' C-10 is a 12 bolt rear-end with 6 lug wheels. But I think the later model trucks had 12 bolt with 5 lug wheels.

[PGSigns]

6 lug was standard on 60 to 66. 5 lug did not come about till they went to front disc brakes. 71 or 72 for that.
Jimmy

[Captainfab]

The '60-'62 Chevy Apache 10 trucks used the Eaton HO322/33 differential which were 6 lug. The '63-'70 C10 truck 12 bolts were all 6 lug.

[rvrfoot]

6 lug.

[Old Radio Tech]

All, do you have any documentation to prove this? The reason I ask is that I went to my local gear shop to order parts needed to rebuild my 1965 Suburban 12 bolt 6 lug GM truck version rear and discovered after the parts had shipped that the axles sent were 5 lug. They think I should have told them I needed 6 lug and I think they should known and asked which I needed if there was a question. Now they are expecting me to pay for round trip freight to and from Alaska and a restock fee.

[PGSigns]

Here is my thoughts on this with more than 40 years of working on cars and trucks. The more exact you are about what you need and the more information you give the parts guy the better your chances of getting the right stuff. The parts books can be a bit lacking and the axles he ordered may say the fit your truck. Not everyone knows what goes in every vehicle and when they get more than 50 years old a lot of folks have never seen or delt with one. If I was in your position I would just have a conversation about you not giving them enough info and them not asking about the axles and see what can be worked out. Everyone has a part in this not being the right stuff and everyone needs to accept part of the responsibility for it.
Jimmy

[chevy_mike]

Originally Posted by Old Radio Tech

All, do you have any documentation to prove this? The reason I ask is that I went to my local gear shop to order parts needed to rebuild my 1965 Suburban 12 bolt 6 lug GM truck version rear and discovered after the parts had shipped that the axles sent were 5 lug. They think I should have told them I needed 6 lug and I think they should known and asked which I needed if there was a question. Now they are expecting me to pay for round trip freight to and from Alaska and a restock fee.

My guess is they ordered conversion axles, as it is common for people to want to switch to 5 lug in the rear, after changing to disc brakes, if using factory style front parts. GM did not start using the 5 lug pattern on truck until '71 when they introduced disc brakes. Prior to that they were 6 lug on 1/2 ton truck back to at least 1949 (not sure about earlier but I guess they were still 6 lug). In '71, 1/2 ton 2WD trucks were 5 lug and 4WD trucks were 6 lug. Starting in '88, GM had a light duty 3/4 ton 2WD truck with 6 lug and heavy duty 2WD trucks were 8 lug. 1/2 ton 2WD were still 5 lug. I believe around '99/'00 2WD 1/2 ton went back to 6 lug and ended 5 lug trucks to this day.

[Old Radio Tech]

I had much more info written down to give the gear guys (numbers off the case and tubes, gears, measurements, etc). They said no need, they had all the info they needed.

[aerotruk63]

I have a bunch of original literature for 60-66. You can go to gmpartswiki.com and look in the original parts books. I agree with you however, the seller should have known or had questioned you as to your preference.

[short&wide65]

Originally Posted by Old Radio Tech

I had much more info written down to give the gear guys (numbers off the case and tubes, gears, measurements, etc). They said no need, they had all the info they needed.

Well, I would tell them that obviously they didn't otherwise they wouldn't have sent the wrong axles.

[aggie91]

Originally Posted by Old Radio Tech

I had much more info written down to give the gear guys (numbers off the case and tubes, gears, measurements, etc). They said no need, they had all the info they needed.

Being as you gave them numbers off of the housing, is it possible that the housing is NOT original to your Suburban?

The codes on the axle tube could have lead them down a path of using a later model housing that was 5 lug standard. Now, that being said, the later model 12 bolt axle (mid-70 and newer) are wider than the 63-mid 70 axles.