68 C10 5 lug axle question please.

[GMJimmy]

Please forgive me for asking a question that has probably been discussed several times on this forum but I don't have the time to search and read them all.

Question is my 68 SWB C10 has a 12 bolt rear end and has 5 lug axles (5X4-3/4") and they need to be replaced. I was under the impression that these trucks had 6 stud axles from the factory? If so, Is there a 5 lug axle from another year that you use for a conversion or do I need conversion axles? The ones that need replacement look like old GM axles.
Thanks for the help.
Jim

[lolife99]

Car rearends are 4.75" bolt pattern.
Trucks have a 5" pattern.
Can you post pics of the rearend?
Either someone has swapped the entire housing or replaced the axles.
You need to determine if it is in fact a truck rearend and which width you have.
Companies like Moser Engineering sell replacement axles for a very reasonable price.

Let us know what you have,...

[Lees68GMC]

You need to determine whether your "12 Bolt" is actually from a Car or a Truck, they are different in several respects. Axles, 5 lug, 5 on 4-3/4" is a Car pattern, the Truck pattern is typically 5 on 5", 1974 C10 to 1980 approximately. Hope that helps, read and ask questions, visit and / or call Motive gear, West Coast Differential and others. Most have tech sections with lots of information. - Lee

Sorry Keith, I was typing (slow) while you posted I guess

[GMJimmy]

Well when I bought this truck I didn't really have a chance to check the bolt pattern but it's definitely a 5 X 4.75 pattern. Front wheels are the same.

Here are a couple of pictures. I don't remember seeing a panhard bar set up like this on a truck before?













I want to change the rear gear ratio and posi unit anyway so if the housing will accept the truck parts I'll do that and change the rotors to a 5 X 5 too.

Any help would be appreciated.
Thanks

[lolife99]

Does it have truck rally wheels on it?
If so its a 5x5 pattern.
Measured like this,....

[GMJimmy]

Keith
Looks like I'm mistaken about the pattern as I was measuring from center to center. If I measure it like your diagram It's 5 X 5. I checked the studs and they are 1/2 Inch.
Thanks.

[michael bustamante]

yup thats a 71-72 c10 rear end

[lolife99]

Get some rear shock relocators and "stand" those rear shock up.
They are layed over at a terrible angle.
All they can do is "pivot" on the shock bolts.
They need to compress to work.
Just my opinion,...

[lolife99]

Originally Posted by michael bustamante

yup thats a 71-72 c10 rear end

It could still be an early (narrow) 67-69 housing with conversion axles.
If you still need to replace them,... you will need to measure their length to get the correct axle.
That doesn't appear to be a coil spring rearend with the cast in panhard bar mount above the center section.
Could be a converted leaf spring rearend with a fabricated panhard bar mount on the right axle tube.

[GMJimmy]

Originally Posted by lolife99

Get some rear shock relocators and "stand" those rear shock up.
They are layed over at a terrible angle.
All they can do is "pivot" on the shock bolts.
They need to compress to work.
Just my opinion,...

I plan to replace the shocks and relocate them as you suggest. I would really like to ID this rear end though. Has anybody got any pictures of a rear end like this showing the panhard bracket like this? I plan to pull the axles in a couple of weeks and start on it and knowing what it is would help.

[michael bustamante]

Originally Posted by lolife99

It could still be an early (narrow) 67-69 housing with conversion axles.
If you still need to replace them,... you will need to measure their length to get the correct axle.
That doesn't appear to be a coil spring rearend with the cast in panhard bar mount above the center section.
Could be a converted leaf spring rearend with a fabricated panhard bar mount on the right axle tube.

yup it could be a converted 73+.
i dont see the mount hole for the factory panhard bar stud

[GMJimmy]

Are the dimensions on these axles like the width the same throughout the years say from 66 to 73 or so?

[lolife99]

Originally Posted by GMJimmy

Are the dimensions on these axles like the width the same throughout the years say from 66 to 73 or so?

No.
Pull one of your axles and call Moser Engineering.
http://www.moserengineering.com/axle...loy-axles.html

[GMJimmy]

Originally Posted by lolife99

No.
Pull one of your axles and call Moser Engineering.
http://www.moserengineering.com/axle...loy-axles.html

Thanks for the advice but I won't be calling Moser. I can get a pair (2) of high quality axles for the price of one Moser axle.

I'll be replacing the axles, bearings, seals and the gears in the next few weeks. I'm new to trucks but have been working on Chevy's for a lot of years. Never really got into the conversions though. It's going to be an interesting few months and with the help of the people on this site it should be fun!
Thanks everyone!

[lolife99]

I thought $260 a pair was reasonable.
Where are you buying two axles for $130?

[GMJimmy]

Originally Posted by lolife99

I thought $260 a pair was reasonable.
Where are you buying two axles for $130?

Actually it's $150.00 pr. I know a guy who works in a place that makes them.

[michael bustamante]

Originally Posted by GMJimmy

Actually it's $150.00 pr. I know a guy who works in a place that makes them.

homey hookups ae always a good thing

[GMJimmy]

Originally Posted by michael bustamante

homey hookups ae always a good thing

You got that right! Only thing is I only need axles once or twice in a lifetime!

[GMJimmy]

I just pulled the diff out of my 68 SWB FS and based on the info above I know the rear axle isn't original (I think). My question is can anyone help me identify it? Casting numbers are 3896839 H249 could be H248 and on the other side it has GM83. It would be nice to know what the axle face to axle face measurement should be. BTW the axles I took out were 5X5 and 31-5/16" 30 spline.

Another question is when did GM use the Cookoo clock posi unit? This rear axle has one.

Any help would be appreciated!
Thanks