Rear axle ID
 

The weather has broken enough that I can get back out in the garage, but I need to get some info together.

My rear axle is a 12-bolt, and I was told when I got the truck that its a 3:73 rear end, with posi. I have the code " N 3856525" stamped into the gusset. I can't seem to find a site to decode this. Is this a truck or car rear end?

Rear brakes are drums, it has 5-lugs, and its on my 66 with trailing arms. I couldn't tell if the rear end ever had leaf perches, since it was cleaned up and painted by the po. Its got Moser axles, and I was told it was a 3:73 posi rear. Anyone have a clue what rear this might be?
Thanks! :chevy:

Re: Rear axle ID
 

On a 12 bolt, you will find the axle code on the pass side tube. Look about six-eight inches out from the punkin, there will be some letters stamped in the tube on the top side a little bit to the front. Post the letters and we can decode them. Hard to say what is actually in there on an old truck without pulling the cover and looking.

Re: Rear axle ID
 

The code on the axle tube is only going to tell you what GM put in that housing. If it is known to have Moser axles, the only way to know for sure what else is inside, is to pull the cover and have a look. It's easy to do and it'll only cost you a cover gasket and a couple quarts of gear oil. Chances are the oil needs changed anyway.

Re: Rear axle ID
 

Ya, I have no problem pulling the cover. I'm not really worried about whether or not its a 3:73, I'm more concerned as to WHAT the rear end was out of. The pass axle code should tell me that correct?

Thanks

Re: Rear axle ID
 

A Yahoo search of the number you posted brought up a few pages with '64/'65/'66 trucks that had that rear end. Can't tell you for sure if it's original to the truck.

Re: Rear axle ID
 

I found the other code stamped in the axle. It reads HA 05020 W.

Re: Rear axle ID
 

HA code was used in 1969 C-10 12 bolt. 3:73.1 ratio

Re: Rear axle ID
 

Thanks very much john!

Re: Rear axle ID
 

The code on the differential that I just purchased is HA 0110k, can someone help me to identify it?

Re: Rear axle ID
 

What I can find shows a 67-68 truck rear end with a 3:73 non-posi
http://www.gmcpauls.com/67-72_chevy.htm

Re: Rear axle ID
 

thanks man, I really appreciate it. i have been searching all over and couldn't find anything.

Re: Rear axle ID
 

haha, I only saw your post because it popped up on my old sub'd threads, since I was the original poster. You really found an old one too!

If you google your axle ID, no info will come up, mainly because the specific code may not match enough others. If you look at the GMC pauls site, and a few others, you can start to get the decoding system down. Main thing is to look at those first to letters, the "HA"...which corresponds to the 3:73 gearset rear. The only trouble is finding the correct ledger to compare it to.

Re: Rear axle ID
 

I have a WC 6 17. DOes that mean a Posi 3.73?
And what does the 6 17 mean?
http://i220.photobucket.com/albums/d...pshnp1o8ri.jpg

Re: Rear axle ID
 

WC = 3.73 posi June 17

Re: Rear axle ID
 

My 12 bolt reads TBA W001 2

Can someone please decode this for me I have been looking all over. I broke and axle and I know this rear end does not belong to this truck.

Re: Rear axle ID
 

To get a new axle all you need to know is the number of wheel studs and the bolt circle, the length plus the spline count.

Re: Rear axle ID
 

Have you been to a parts store lately? The last time I went in to get a clutch master cylinder the kid actually asked me if I had an automatic or manual... It would be much easier if I could tell him what the axle was in or at least give them a year.

Re: Rear axle ID
 

Yes I have and I certainly would not even consider going to one of the chain parts stores to get an axle for an older truck. Get the info I mentioned above and then look online and see what you can find. You must have some sort of idea what the differential is? What year of truck is it in now? Is it a 2wd or a 4wd? What makes you think it is not original?

Take a look here.

https://www.yukongear.com/partslist....SpotlightID=14

Re: Rear axle ID
 

It's 4wd its a 12 bolt posi which wasn't offered in 85. Why are you even arguing the point? I just asked what the axle code translated to. The truck is a pile and I need a new axle. I don't want to wait a week ordering online and getting the wrong thing. A big box box store can help me just fine if I can find the year the rear end is from.

Re: Rear axle ID
 

Just trying to help you figure out what axle you need since there does not seem to be a listing with that build code.

A 4wd 12 bolt narrows it down to the years of '63-'79. There are only 2 different lengths of axles used within those years.

Re: Rear axle ID
 

OK well that's what's the axle says. I ordered a 75 one I'll find out tomorrow if I chose well.

Re: Rear axle ID
 

Thanks Capt, I appreciate your help even if some people don't;)

Re: Rear axle ID
 

Hi trying to find what ratio is on my axle this is the number I have found gm73 stamped on the diff casing one side

And the other side it has this number 3896839 and there is an n underneath that thanks any advice would be great thanks Pete

Re: Rear axle ID
 

Those numbers are just casting numbers and will not tell you anything about what GM put inside the housing 50+ years ago. For that info you will need the build code stamped on top of the passenger side axle tube. There is no guarantee that the original parts are still inside. Myself, I would just pull the cover and have a look. More than likely the oil needs changed anyway.The differential is one of the most neglected parts of a vehicle.

Re: Rear axle ID
 

Thanks captain a have since come across this number which way help.
Kax w25511 thank for your help Pete