The Stovebolt Site Forums The Shop Area Driveline ring and pinion choices

I am new to this forum and am learning that I know less and less all the time. I have a 1959 Chevy 1/2 ton truck with a flatbed, 3 on the tree, and a 235 six cylinder. It has a real low geared rear end. I would like to get the ring and pinion gears changed to some where around a 3.0 to 1. The highest that I have found is a 3.38 to 1. I am not going to be hauling much but would like to go down the highway better and get better mileage. I would really like to keep the 3 speed and it would be nice to not have to change the whole drive line. Does any one have any suggestions?
Thanks a lot,
Gene

shouldn't be "real low geared", just the standard 3.90 .... 3.38 is the best you'll find for the original rear, but that'll give you a decent highway speed and still let the 235 get you rolling from a stop - if you want lower highway RPM yet, get an original style [55-70] OD 3 speed that'll bolt right in, but the 0.7:1 OD on top of a 3.55:1 rear might leave you wanting a stronger engine

and welcome to the garage Gene, lots of help around here

Bill

I second the 3 speed od with stock 3.90 gears.

I "third" using the 3 speed column shifter with OD.

I will give you another option. Find a 1957-1959 gmc 1/2 ton with a 3 speed. The 57-59 gmc trucks ran a spicer rear with 3.08:1 rear gears. I had that rear and a 3 speed with a 270 6 cylinder in my first truck. I never did understand why so many people were complaining about not being able to drive the freeway.

I bought a set of 3.38 gears for my current 59 gmc 1/2 ton. My 447 inch pontiac v8 motor destroyed the axle. I currently have 3.7:1 gears in my 59 with a .73 OD. Sometime in the near future, I will be changing the gears to 4.3:1. I want a little bit more grunt from my truck.

Higher gears like 3.08 are great for economy, but poor for acceleration and towing. Lower gears like 3.90 and 4.11 are great for acceleration and towing, but not so good for cruising or economy... unless you have an OD. 3.90 gears with a 27%OD will feel like 2.85 gears in OD. 4.11 gears will feel like 3.0 gears in OD. With an OD you get the best of both worlds. If you crunch the numbers, A truck with 3.90 gears and od will be tacking less than a truck with 3.08 economy gears and no od on the freeway.

Tire size will also affect gearing. In my case I had 28 inch tall tires with 3.70 gears. When I changed to 31 inch tires, it made the 3.70 gears feel like 3.34 gears. There was a "loss of gearing" when going to the larger tires. In my case the loss of gearing was not desireable. Changing my 3.7 gears to 4.11 will put me back to where I started. Changing to 4.3 gears should make my truck pull a little better than before.

How do the 3 speed od transmissions work? I have heard of them but have never seen one. It sure sounds like the way to go if I could find one at a reasonable price. For right now I am thinking of starting out by going to 16" wheels. I should be able to get some at the salvage yard pretty cheap and I am going to need tires soon anyway. That should help a little until I find a rear end or an OD transmission.

All there is to know about the Borg-Warner 3 speed overdrive.

Thanks for all the information.I got to thinking and my truck used to be a 4 wheel drive so I think maybe it is a little lower geared than most. The rear end is howling anyhow so I have another one that is probably a 3.90 to 1. If the gears look good I will probably put it in and start looking for a 3 speed overdrive. It sounds like that would solve all my gearing problems.

How many lugs on your wheels? 6? 8? other?

If your truck has the 1/2 ton rear, 3.90 and 3.38 gears are about the only options. There was a very rare 4.11 gear set, but it is not likely to be in your axle.

3/4 ton trucks likely have a 4.57:1 ratio
1 ton trucks likely have 5.14:1 ratio.

When you say used to be 4wd, does that mean a NAPCO 4wd, or something that may have been cobbled together on a farm?

It is 6 lug and the 4 wheel drive was supposed to be from the dealership and not factory. The guy who sold me the truck was a liar so I really can't be sure of anything unless I can verify it myself.

Look for 1 inch letters cast into the front of the axle that says NAPCO. It should be visible from the front bumper when looking under. With a NAPCO front axle, there is a 50/50 chance of it being factory or an upfit. Without the NAPCO axle, there is a "ZERO percent chance" it was factory. Lots of folks swap dana 44 fronts or 10 bolt fronts on these trucks.

If you have a NAPCO axle and transfer case on your truck, you would have a fairly rare truck. Lots of people looking for your axles and such.

Of course there is also the possibility that the previous owner did a frame swap and put the old sheetmetal on a more modern chasis. Usually done with a 70s blazer frame. But others have also been used.

The guy I got it from kept all the 4 wheel drive assembly and swapped front axles to a 2wd front axle. I only know this because I saw the truck before he switched it out. The front axle that is under it now is just an ordinary 1959 chevy front end.