Rear end axle change 1962

[Swed]

Hi guys,
Maybe I suck at searching and couldn't really find what I was looking for.
My idea is to change rear end axle on my 1962 stepside.
For the reason to get a better gear ratio, preferable 3.08 and 5 lug.
The truck is already with coil springs.

I found one rear end on CL from a 1986 Chevy truck for $150. Don't know the condition yet.

I'm wondering about the width on the current axle and the 1986 axle.
My truck is now on the other side of the pond for the export to Europe in 2 months so I can't measure.. Can someone be so kind to measure it?

I am aware of the different widths on the 60-62 from other models.

U think I can purchase the rear end and won't have too much headache to do the work? Or do you have other ideas what to use?
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[Bret B]

The '86 is wider than the '62 you have now. It will fit, but remember the '86 rear uses metric fasteners and some other minor differences that escape my mind right now.

If you really want a lower ratio and 5 lug, you will have to make some decisions. You can simply re-gear your rear end and install new axles. Or, go Impala SS '96-ish era if I rememeber. Or, Ford 9". Or, deal with the width and figure out wheels and tires.

[Swed]

Hi Bret,
Thanks for info.
Just as I thought, that its wider. Question is how much?
I haven't found any gears that fit my 62 though.. As far as I understand they used Dana 44 and 10 bolts and I don't know what's under there now..

I'm considering also the cheapest alternative, new axle with some work or renovate and fix the current one? Only gears is about $200-400 and then I'm still stuck with the 6 lug issue..

I have new wheels already and disc conversion is on the go to 5 lugs in front..
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[PoDuck]

If you are asking these questions, you probably don't want to undertake a rear end gear swap on your own anyway. It's a bit tricky getting things lined up properly, and should probably be done by someone that has some experience, unless you want to have a small explosion of rear end gears after a few hundred miles.

If it is truly a dana 44, I don't know why you would have trouble finding gears and parts. The local parts store should have them in stock, as they are very common.

[Captainfab]

The '60-'62 Chevy C10's typically have the Eaton HO32 differential. There is only one other gear choice other than the 3.90's that are likely in it, and that is 3.38 gears. I believe Yukon gear makes them. But changing gears does not address the 6 lug to 5 lug issue. No one makes conversion axles for those differentials. So you would have to have a machine shop plug and re-drill your existing axles. But there is also the possibility that your axles are worn at the wheel bearing surface.

That '86 8.5" 10 bolt differential is going to be 1.5" wider than your current differential. It will be setup for leaf springs, and a different shock location. To install that differential under your truck, the leaf spring perches and shock mounts will need to be cut off. Then a set of trailing arm mounts and a panhard bar mount will need to be welded on. This needs to be done with careful attention to the correct pinion angle.

An option for you would be to find a '63 to early '70 12 bolt, hopefully with 3.07 gears. The trailing arm mounts will still need to be moved, as the '60-'62 trailing arms are farther apart. The '63 & '64 12 bolt will have the same panhard bar mount as your current differential. The '65-'70 uses a shorter panhard with the mount in a different location, but is easily modified to fit. Now on to the 6 lug to 5 lug issue. There are aftermarket 5 lug conversion axles available for the '63-'70 12 bolts, as well as posi carriers, lockers and many gear ratios.


Either way, this may be a little difficult for you to coordinate from where you are, unless the person doing the work for you is familar with the work involved with changing the differential.

[Swed]

Captainfab,
Ah! this is the kind of information I need.
Thanks so much for this!

I'll be looking for another axle then, and thanks for adressing the issues.
I've had my mind in this direction too but it's always good to hear it from someone that have done it before about the things that needs to be done to it.

Have a great day!

[Captainfab]

Not a problem, glad to help.

Who says the Swede's and Norwegians can't get a long

Originally Posted by Swed

Captainfab,
Ah! this is the kind of information I need.
Thanks so much for this!

I'll be looking for another axle then, and thanks for adressing the issues.
I've had my mind in this direction too but it's always good to hear it from someone that have done it before about the things that needs to be done to it.

Have a great day!

[Brad54]

If your truck has a round cover on the back side of it, and the entire differential drops out from the front, then it is the Eaton unit.

If it has a cast center section, and a rear cover that ha 10 bolts, it is a Dana 44. (Here's a pic: http://www.speedwaymotors.com/Dana-4...FQ0GnQod4D0AMw)

If it is a Dana 44, you're in luck--The Dana 44 is the most used rear end in the automotive industry. It was found in everything from Studebakers in the '50s and Checker cabs through their entire production, to current Ford Explorers and other SUVs, Jeeps, and there was even a version of it in Vipers and the pre-Transaxle Corvettes.

What this means is that you can have your pick of gear rations, from high 2-series, to 6.00 and above, and you can find new posi traction units everywhere.
Jeep guys often want to put larger gears in their jeeps (4-series), so 3-series differentials are plentiful. I have a posi unit from a Jeep and 3.42 gears in my '61 Suburban.

Rebuild and bearing kits are plentiful as well.

This will not solve your 5-lug axle problem, but if you really want 5-lug axles you can have a machine shop plug and redrill the flanges, as was said.

The GMC trucks came with a Dana under them, while it was an option for the Chevy trucks.

In '63, they all switched to the 12-bolt rear.

I think a Dana 44 is the best rear out there for our trucks, due to availability of parts, including superior OE gear sets, rather than aftermarket gears.

If you can't find an original, or want to go another route, you can take your stock rear end and have a shop cut off the perches and panhard bar mount, and swap them over to your new rear end.

Hope this helps.

-Brad

[short62]

I'm swapping out my rear axle on my 62 GMC short step to a 85 C10 10 bolt with the bigger 2-3/4 x 11-5/32 brakes. before I start the conversion will my tires clear my rear fenders? I'm planning on using stock 15 x 6 steel rims. If its too tight clearance wise should I get the 11 x 2 shoes and drums?

[Pappyx3!]

Originally Posted by short62

I'm swapping out my rear axle on my 62 GMC short step to a 85 C10 10 bolt with the bigger 2-3/4 x 11-5/32 brakes. before I start the conversion will my tires clear my rear fenders? I'm planning on using stock 15 x 6 steel rims. If its too tight clearance wise should I get the 11 x 2 shoes and drums?

I did this same conversion on my 62 this winter, except I went with the GM 12 bolt, I used CaptainFab's perches to accmodate the trailing arm mounting. Regarding the tire question, For now I am using the 80's stock Ralley wheels that I have, equipped with 255/60/15's That is the widest tire that I can get under the rear since the truck has been lowered.

Good luck!

Pappyx4!

[vince1]

My 66 3.73 was trashed so I put in a 3.07, I believe from a 70 which still had the six stud axles. Personally with so many trucks going back to six stud I don't know why anyone would want to go to five but each to their own.

What about using a newer than 70 12 bolt rear end that has 5 stud axles, coil springs, and pan hard bar setup, if there is such a critter?

[Captainfab]

I can not say for sure on your fender clearance as I don't have any stepsides. I do know that the stepsides have less clearance than a fleetside. I would think that with those skinny wheels you should be fine. Changing to the narrower brakes will not change the WMS to WMS dimension of the differential.

Originally Posted by short62

I'm swapping out my rear axle on my 62 GMC short step to a 85 C10 10 bolt with the bigger 2-3/4 x 11-5/32 brakes. before I start the conversion will my tires clear my rear fenders? I'm planning on using stock 15 x 6 steel rims. If its too tight clearance wise should I get the 11 x 2 shoes and drums?

[Captainfab]

Most of the '71 & '72 C10 12 bolts of course are setup for trailing arms and coils plus they have the 5 x 5" wheel stud pattern. But in my experience they are difficult to find and $$$$$ when you do find one.

Originally Posted by vince1

My 66 3.73 was trashed so I put in a 3.07, I believe from a 70 which still had the six stud axles. Personally with so many trucks going back to six stud I don't know why anyone would want to go to five but each to their own.

What about using a newer than 70 12 bolt rear end that has 5 stud axles, coil springs, and pan hard bar setup, if there is such a critter?

[short62]

Thanks Guys I'm new to the Forum and I've been getting great information and tips from the members on the 60-66 Forum. This is my first 62 build very different from a 69 I did 15 years ago. You're right Capt the 71-72 12 bolts are hard to find and pricey if you do find one. Reason I went with a 85 C10 10 bolt was it was cheap and had 5 lug. The 10 bolt should fit. What might help I have two sets of factory 15" rims. The 85 rims have 3 1/2" backspace. The other set is off a 87 Burb it has 4 1/4" backspace. I'll try both sets and see which ones fit better and post my results. Thanks to all

[short62]

Update on 85 C10 swap. Yes it is 63.5" inches wide 1.5" wider than the Dana 44 I removed as Capt Fab mentioned. I found plenty of clearence on my stepside fenders. I'm using 15x6 rims off of a 87 burb with 4 1/2" backspace with P225 70 R15 coker wide whites. I can easily go with a 15x7 rim with P245 70 R15's with no problems. It's lowered 6" with 4" drop coils and 2" lowering blocks. pinion angle seems ok at this point. Hope this helps.