The Stovebolt Site Forums The Shop Area Driveline 1959 Apache rear end questions

I have a 1959 Apache 3200 stepside with a 235 engine. I took the cover off the rear end and counted the teeth (39 and 10) so I know I have the 390 gears. I mostly drive highway miles but do occasionally pull a vintage boat with the truck and put it in at the lake ramps. I would like to change te rear end ratio so I could drive 70-75 down the Interstate but also be able to pull the little boats (500-600 lbs.) out of the lake without slipping a clutch.

What ratio do you guys recommend and where can I get them at?

P.S....I wish the little trucks had a 2 speed rear end option.

I would like to add that I can currently do 70-75 mph down the Interstate but not at the rpm's I would like to have. I would like to achieve the 70-75 at around 2600 rpm's.

There are many ways to achieve your goal.

1) 3.38 gears to put in your rearend
2) Change out the rearend for another with more gear choices
3) Install an OD transmission

I have a 59 gmc 1/2 ton longbed, and I would reccommend option (3)

Changing the gears also changes the ability to pull a load and the ability to accelerate. Put an OD transmission in and you can have your cake and eat it.

I also agree with option 3. If you have a 3 speed truck, swapping in an SM318 with the Borg-Warner overdrive is the easiest way, as it was a factory option.

I do have the three on the tree.

Where can I get a SM318 with the Borg-Warner overdrive and what would it cost?

You might try down in the Swap Meet area, Ebay and Hemmings are also good places to look. You can also find them at car show/swap meets, too. Don't overlook a passenger car version of the transmission, they are essentially the same as the truck version, there's only a few differences, depending on year. Mainly, you may need to swap the side cover and shift arms from your existing transmission. Expect to pay about $100-150 for one, expect to at least put new gaskets and seals in it. If possible, se if the solenoid works, as they are not available new (good used ones can be found, though).
I installed one in my 3200, best thing I ever did for it. It'll cruise at highway speeds easily, but still have the takeoff power for in town driving. I like them setup more or less as the factory intended, with the overdrive working automatically. I did add a switch to cut power to the solenoid when it's locked out for in town driving.

Thanks, I will start the search. I think the overdrive option is the best.

I second the emotion. I love the one in my burb.

I agree that The 3 sp OD is the best way to go but the days of finding a good one for $100 to $150 is over. The last one I bought at a swap meet cost me $125 and was very needy. I have numerous parts in stock but it needed a mainshaft which was $100. I wouldn't try to put one in service without tearing it down as most now have many miles on them and need bearings among other parts. In most cases I have found the BW components to be good but the syncros and other trans parts well worn. The good part is that the gears and other components can be switched from a regular 3 speed to build an OD. Except for the mainshaft.
Fred

I agree with all the good comments given here. I would add that it is well worth the effort to study the Chevy Shop Manual section on the o/d transmission and set your o/d up as in the manual ( including the gas pedal kick down switch, relay, etc.). The manual also gives complete instructions on how the o/d trans drives and operates. The bracket to hold the kick down switch on the carburetor might be the most difficult to find but can be made out of a piece of 1" x 3/16" steel. I have a drawing of how to make the bracket(sent to me by a fellow Bolter) if you can't find an original. The three on the tree o/d and 390 combination is very sweet and fun to drive,

I have a '59 3600 Fleetside. Original gears were 4:56, which made highway driving impossible. Transmission is the SM420 4 speed, but the granny gear means that it's really a 3 speed unless you're pulling a stump. I replaced my rear end with a Dana 60 from an '87 Dodge 2500. Limited slip with 3:54 gears. Had to widen the spring perches and buy a new yoke for the U-joint, but other than that, it was a bolt-in operation. I can now cruise with ease at 70+, although my truck is an original V8 truck with a 350 in it.

Chris