The Stovebolt Site Forums The Parking Lot '60-'66 Trucks KS10 rear end

I have this 1963 C20, it has the KS10 No-Slip differential. Can this be rebuilt to a different gear ratio?

I am not sure what ratio it is, however, I may want to get something taller. And, I would like to keep it 8-lug.

Yukon Gear sells kits with everything you need to rebuild your diff. in lots of different ratios.

That appears to be the GM Corporate Eaton HO52/HO72 style rear end. It is more than likely a 4.57:1 ratio. There is a huge amount of information on this site regarding that differential. To the best of my knowledge there is only one "higher" ratio available and that is a 4.10:1 from 67-72 trucks with an auto trans. It may be even more difficult to find a gear set for a "NoSpin" unit. You may be better off installing a manual overdrive, Gear Vendors overdrive, or an automatic overdrive transmission and leave the rear end alone.
Fred

The overdrives seem quite pricey!

What automatic trans would work?

Will a 700r4 bolt up?

Or, is a TH350 better for the low geared rear end?

“Will a 700r4 Bolt up”.

Bolt up to what? If your talking the 292 in your signature line, you would need an adapter unless the bell housing is the same as a SBC.

Yes, I was referring to the 292, where do they sell these adapters?

If I do bolt up a 700r4, will it get me higher gear on the freeway, with that rear end I have now?

You will have the overdrive of the 700r4 but 1st gear to 2nd gear shift will be at about 5mph pretty much normal after that.🛠
Let’s wait on the experts before jumping on the adapter band wagon.

I checked with that overdrive company, their OD setup for my trans is about $3400!
That’s a pretty big investment, definitely something I would do only if I was sure I was going to keep the truck. At this point, just not sure. Need to do the brakes and get it rolling down the road first.

I really want to know my options though.

Also read something about these no-slip differentials causing the wheels to chirp when going around corners, is this true?

700-R4 would bolt to the 292, but not the strongest but can be improved with stronger internals. Getting the TV (throttle valve) cable set up correctly is a must, that's the only thing that controls line pressure. G.M. changed the naming and the became 4L60. Later 4L60E was better unit but got to have a computer to run it.

If you are lucky you might be able to find a NP540 od. Harder to find than NP540 direct but they are out there, some will spline right up to your clutch. OD units have 3rd to far right & up where direct drive have a normal shift pattern of 3 center & up, 5th far right & up.

No spin takes some getting use to as the inside tire will drive the rig, outside tire will overrun until traction is lost.
If you lay the hammer down coming out of a curve it may tend to want to go straight. They were used in school buses when I was young so they can't be that bad!
I have put that style in my 2000 K2500 10.5" axle & love it.

I thought I had read somewhere that the 292 bell housing was the same as a SBC. That’s why I said let’s wait. Thanks BC59.

BTW, I’m running a 700r4 behind a 400+ hp 350 in my ‘62 C-10 with only the short 1-2 shift issue.

Are there any other 5 speed overdrive transmissions that would fit the truck with a 292?

Overdrive options include but not limited to:
Manual:
SM319 Muncie 3 speed w/BW overdrive, factory option for 55-65 trucks. Available, reasonable.
Saganaw 3 speed w/BW overdrive, factory option for 66-70 trucks. Limited availability, costly.
A833 New Process 4 speed OD, used on mid 80's GM trucks and misc Mopar vehicles. Rare, costly
5 speed factory option used on late 80's/90's trucks. Unknown availability, cost
BW T-5 used in S10 vehicles 80's & 90's. Available, reasonable

Gear Vendors OD w/adapter. Use existing SM420 4 speed trans, bring lots of money

Automatic
700R4, available, semi reasonable
2004R, available, semi reasonable

Fred

Note: All of the above will require driveshaft mods, some will require shift linkage changes.

The driveshaft mods would not be a problem, I’m more concerned about mating those to my bellhousing and output shaft.

The Borg Warner T5 sounds like a good option.

What about a BW T45 that was removed from a 1996 Mustang? Would it fit?

From Moderndrives.com

The T-45 five-speed overdrive transmission was developed primarily for high-performance cars with relatively high-engine torque requirements but is adaptable to other light-duty applications such as sport utility light trucks.


What kind of racing you plan on doing?

4.10 3rd members are around.

All 230/250/292 6 cyl engines use the same bellhousings as small block and big block V-8's. Subsequently, the transmissions used in those vehicles will mount to the bellhousing as well. Output shaft issues can be addressed with the driveshaft mods. Ford transmissions will not fit GM vehicles without an adapter. Look up Advanced Adapters. They are generally expensive as well.
Fred

Thanks for the info on the adapter company.

Thanks to all for the replies!

I sent you a PM.
Fred

I found a T45 nearby, wondering if is worth pickup and installing. Hoping to get that overdrive going.

I think the trans is out of a Ford; would that mean I need a different bellhousing or will it just not work?

Save your money, it's not going to work.
Fred

I wanted taller gears but I kept burning up 700R4s and I couldn't justify a 5 speed, so I simply pulled an axle of a 97 suburban with 3.08s to replace my 4.10 out of the 65. It made the stance a few inches wider but so did my front disc brake conversion so it all worked out.

Perhaps this could be an option.

I fail to see the relationship between having a 4.10 rear end and "burning up 700R4's". Traditionally the main problem with 700R4's is not adjusting the throttle/kick down correctly.
Any replacement rear end assembly in that era truck will require extensive welding. If you have the skills and the equipment or can pay someone you are good to go. Other changes to consider are universal joints, brake lines, and parking brake components.
Fred

That's because there is no relationship, Fred. I had bad luck with automatic transmissions, including 2 700R4s and a turbo 350. (Poor quality rebuilds, not because I had 4:10 gears.) I went back to a 4 speed manual and just swapped rear-ends.

What extensive welding do you think is required? The kit for my C10 with trailing arms was bolt on. I fail to see where full leaf springs would require welding as well. Like I said you have to torch off the shock towers on your donor but that's it. The u-joints can easily be easily be adapted (I went to a driveline shop and told them what different sizes I needed and they put it together in less than a day.) Brake lines required one brass adapter. I never hooked up the parking brake but could do so easily.

Long story short, it is much easier to swap rear ends than it is to change and adapt transmissions. I know. I've done both.

Since your conversion was for a C10 and the subject of this discussion is a C20 there could very well be some differences.
However, it sounds like a great opportunity for you to write up a "Tech Tip" for the bolt in conversion of a 97 Suburban rear end with suspension to 60's C10 and C20 trucks. I'm sure there are lots of owners of these trucks that would be interested in a detailed description of the parts needed and the processes involved.
Fred

You have a point, because the C10 has trailing arms. The C20 might just have full leafs, but I'd imagine as long as the axle tubes are the same size you could unbolt one and bolt in the other.

I did the conversion in 06 and never took pictures so a write up would be difficult to understand. But after swapping transmissions back and forth (causing me to cut out then reinstall the transmission crossmember) and try to change a ring and pinion, swapping the entire axle in a couple of hours was a dream.

Not to mention I put new brakes on the rear end in March, and parts were much easier to find.