The Stovebolt Site Forums The Shop Area Driveline 1998 S10 six lug

Happy New Year brothers.

I have found a six lug S10 rear axle. I want to swap this axle into my 1942 3/4 ton. Before I drop the bucks to buy it, I wanted to ask the advice of our resident experts, or anyone who has used the S10 six lug to upgrade a 41-46 3/4 ton truck. If you have any experience or advice about using this axle in the Art Deco series of trucks, I'd be very thankful for your expertise.

Honored to know you all, and share our common interests.

A six lug S10 axle would be a new one on me, as I have always been under the impression that they had a five lug pattern.

To the issue of strength, contemporary wisdom would answer negative, that the 3/4 ton axle in new trucks is larger than the half ton axle, and that again larger than the S10.

Thanks for your response. I understand what you're saying, and I agree that the standard S10 axle may not be a good choice for my 3/4 ton.

My limited research on this 6 lug S10 axle indicates that the 4x4 S10s had a six lug axle set up. Since I have already swapped out the ole stock Muncie 4 speed trans, it sort of makes sense to match the axle to the trans. I don't really do any heavy hauling in my 42 3/4 ton, just the occasional run to Home Depot, or Tractor Supply. Living in South Jersey, we also do not have any hills that would challenge the driveline in any way, even with a full load.

Because I'm running a 1962 Chevy 235, I'm not producing enough torque/horsepower to break the S10 diff/axle. Given the lack of available/usable parts for the OE 3/4 ton rear, and it's deteriorating condition, I need to do a swap anyway. The 3/4 ton rear parts are even harder to find. I've been looking for new side gears for more than 3 years now. With that issue, and the worsening leaks and noises, it's not gonna last much longer anyways.

I've asked the seller for the numbers from his axle so, we'll see what that tells me about suitability for my truck.

Your 3/4 ton probably has 8 hole wheels. You will need different wheels & they would not match the front.
George

Thanks for your response, and Happy New Year. My 42 BL 3/4 ton has OE six lug 15 inch wheels. That's why I want the 6 lug version of the S10 rear axle.I will still need to confirm the lug pattern for this rear axle, to make sure it matches my 1942 bolt pattern. Enjoy the holiday.

I've never heard of a 6 lug S10 rearend. The 03-05 Astro van had a 6 lug rearend that used 28 spline axles and 7.5 ring gear, which is similar to the S10. The 04-12 Chevy Colorado used a six lug rear too. It is basically a beefed up version of the 7.5 " 10 bolt. These rears can be had for cheap in the salvage yards. The only issue is with the rim centers and they use metric lugs, so you'll have to choose your rims accordingly. The Colorado rear uses a 8" ring gear and 28 spline axles. It's similar to what was used in the Trailblazer and H3. Unfortunately, the Trailblazer used a small 6 lug bolt pattern, however the H3 used the 6x5.5 , same as the Colorado. The Trailblazer and H3 had a 8,.6 and 30 spline version also. They used the same housing as the 8" rears, so it may be possible to build a heavier rearend with parts out if the GM catalog, but probably not really worth the effort. Like you stated in a previous post, the 235 drivetrain doesn't gave enough power and torque to break it anway.

Thanks for your response. The seller stated this was an S10 rear that he had rebuilt. I'll take your word for the Blazer and van axle information.

I posted this thread because I have limited knowledge of the later Chevy vehicles and even less knowledge about the rear ends.

As I had stated, I need to replace my OE 1942 rear axle because parts are no longer available, it leaks badly, and is becoming noisier each year. I'm looking for advice concerning the best candidate for a replacement axle in a 42 3/4 ton. Primary requirement is retaining my OE 6 lug Artillery wheels. I like the stock look, and I want to avoid any serious mods to the frame. I'd prefer to modify the axle housing rather than cut on the trucks OE frame.

All input is welcome. But it sounds more and more like I will need to make a decision by this spring.

Thanks again, and Happy New Year.

Here are some parts for a 1942 rear axle.
Some are for 3/4 ton.
You most likely are aware of these companies, or, you are set on finding a more modern rear end.

https://www.oldchevytrucks.com/cart...FRear+Axle+%26+Differential&station=
https://www.chevsofthe40s.com/shop/...p;searchtype=FT&method=KeywordSearch
https://www.rockauto.com/en/catalog/chevrolet,1942,truck

Tim:

I appreciate your advice. I have already purchased all of these parts. It is not possible to find a decent set of side gears for the 1942 3/4 ton rear diff. Also, the spider gears are no longer available. The gears I have are badly scored, and IMO, no longer usable. Rebuilding the OE diff, while replacing only some of the parts, is not a practical solution. Most likely would begin leaking again within only a few miles, and get noisy not long thereafter.

I considered doing the pumpkin swap for a GM 55T diff, (tech article on this site) but quickly discovered that these parts are also no longer available for the GM 55T. I have not found any supplier who is making these gears. No professional service is willing to take on the task of fabricating new gear sets for this rear end.

As I posted earlier, I've spent more than 3 years now looking for these diff gears, with no luck. It is now time to move on to a more serviceable rear end, or park the truck till I find usable gear sets. Not willing to do the latter.

If you know of a good source for 1942-46 3/4 ton diff side gears and/or spider gears, or the same gear sets for the GM 55T, I surely would appreciate that assistance.

Thanks again for your response, and Happy New Year.

Several of the Japanese pickups like Toyota, Mazda, Nissan, etc, plus Dodge Ram 50 and older Ford Couriers run the same 6 lug bolt pattern as the Chevy pickups. You might expand your search to include some of them, as they're mostly rated as "1/2 ton" weight capacity. The older Toyota Land Cruisers also run a 6 lug wheel that's a direct swap with the 6-lug Chevy wheel.
Jerry

Thanks Jerry. I'll give these some consideration. I have found a new set of side gears for my GM 55T center section. As a result, I'm now leaning back toward using that 55 1/2 ton differential in my OE 1942 axle. Time will tell as I completely disassemble the center section.

Thanks again, and Happy New Year.

Well ... I have found a NOS set of side gears locally. I also now have two good used spider gears on the shelf. The issue that I now face is that the differential carrier is also badly scored. While I'd like to replace the carrier, it's doubtful I can find one that is in decent shape. I'm going to take the one I have now down to my local machine shop, and ask them if there is anything they can do to address the heavy scoring on the surfaces that mate with the side gears and spider gears. Anyone ever tried to repair the gear bearing surfaces of a diff carrier? Frankly, I think the carrier is beyond repair, but I'll ask the experts. I really would like to keep the OE appearance of the original axle housing, if at all possible.

I am still open to additional suggestions/advice/experience, as to what rear axle would be best for installation in my 1942 3/4 ton. Thanks to all for your advice, and answers to my uninformed questions. All the best in the new year.

Do the side gears have hard steel thrust washers between the gear and the carrier? If not, a really accomplished machinist should be able to machine the scored area back a little and fit that type of washer. A lot of later model rear ends had that type of arrangement, and a washer doesn't care if it's in a Chevy, Ford, MOPAR or even a (shudder!) Studebaker!
Jerry

The side gears and spider gears did not have thrust washers. I printed out a parts diagram of the GM 55T differential, and these washers were never a part of the OE design. I agree that a good machinist should be able to polish the surfaces, and fabricate some thrust washers to fix this problem. I assume the question will be, how much wear has occurred, and can the carrier be cut down, and then brought back to original specs by the thrust washers? Thus far, the ring & pinion look good, and being a 3.90, they should be an improvement over the OE 4.55

I'll be disassembling the carrier today, and taking it to my shop for evaluation. I'll post a followup when I have some more information.

Still looking for recommendations for a good replacement for the OE 3/4 ton axle. Seems this GM 55T 1/2 ton differential swap is the best way to upgrade the OE 3/4 ton axle. If this cannot be done, then replacing the axle may be my only remaining solution. I'm still leaning towards the 55-70 Chevy C-10 12 bolt, because it is still GM, and it is widely supported for parts and upgrades. Aside from that, the Dana axles from the jeep series may also be a good alternative. I'm not a fan of putting a Japanese axle in a 1942 Chevrolet truck.

Parts don't care where they come from, or what vehicle they're installed into. Vehicle owners, on the other hand, can be pretty prejudiced. If I could find one with 6 lug axles, I'd choose a Ford 9 inch rear end over anything GM has ever made. It's what virtually every NASCAR racer is running, and there are hundreds of options available about ring and pinion ratios, limited slip center sections, disc brakes, custom axles, and other stuff. Strange Axles can probably make a set of 6-lug axles for a 9" rear end that would let you bolt the original wheels on with no problems.
Jerry

Thanks Jerry

I hear ya concerning the Ford 9 inch. I agree that they are a great choice. Thus far, the research I've done tells me that acquiring and modifying a usable Ford 9 inch, or having one built to my specs, would cost me somewhere between $2K and $3K. More than I want to spend on this upgrade. Of course, as I still do not have an estimate from the machine shop for reconstruction of the GM 55T, I have not taken the Ford 9 inch option off the table.

I'll be taking the GM 55T to the shop on Monday morning for an evaluation. Hopefully, the tab for it's repair will not approach the cost of a new Ford 9 inch.

Well, since I'm accustomed to spending $10K+ just for a crankshaft, connecting rods, and pistons for some of the round track engines I've built, sometimes my perspective on what's an acceptable budget gets skewed. Of course, I'm usually spending "somebody else's money" who wants to win races. Good luck on finding something that works for you.
Jerry

I put a diff in my 54 3100, it came out of a 78 4x4 chev suburban,12 bolt posi, 6 stud axles, stock springs etc. Had to rework the mounting a bit. Its been in there 30 years now and i havent had to touch it once,except to service it once in a while. Partsvavailabikity is still good.

Thanks for the recommendation. I looked at the later Suburban & 1/2 ton axles as an option. The main issue would be the WMS to WMS measurement, and the mounting configuration changes. My OE 1942 3/4 ton axle is 61 inches WMS to WMS. From what I can find online, the later axles are 63.5 inches. That would push my rear wheels out a bit too much. Since I do not want to abandon my OE artillery wheels, I'd like to keep the total difference down to an inch or so, and stay with the 7/16 wheel studs. That limits my options for a Chevy rear end to the 1955-70 pickups, and Camaro/Chevelle/Firebird from mid 60s to mid 70s.

I'll continue the research.

Agree Jerry. The budget for this is going to have to grow, if I am to wind up with a quality result. The more I look, the more I realize that there is no easy, cheap solution. Even buying a 12 bolt from the correct source vehicles would still mean it has to be gone through by a pro, reconfigured to my requirements, and brought back to specs, before it could be installed. Given the cost of that acquisition and repair, it may be advisable to simply cut to the chase, and have a Ford 9 inch built from scratch, to my specification and needs. At least then I could be sure it would be a straight bolt in solution, without mods to the frame.

BTW, went to my local machine shop yesterday and found that they, "would not be set up to cut and polish" that 1955 GM 55T diff carrier. I'm going to check a couple more shops locally before I abandon that approach. However, it does look more and more like the custom rear axle may be the best alternative. If I'm forced into that solution, I will spend a little more, and order the Ford 9 inch.

Thanks again for helping a rear axle novice to educate himself, and seek a solution.

A brief update. I have found a local machinist that is willing to tackle the job of rehabilitating the 1955 GM 55T differential carrier. He's going to machine it down to a polished surface, and then I will need to have some thrust washers custom made. Worth a try. I'll post again after this effort is completed.