Projects whats the tallest gears that fit in a stock 59 apache rear end?

Hi all! Does anyone know what the tallest gear ratios that will fit in a stock 59 Apache 3/4 ton. Its a 235 four on the floor. It has an extraordinarily low rear end in it, I bought it from the original owner and he ordered it to be a delivery truck. I want to replace the gear ratio in the rear end just to get a little better highway speed. I'm thinking 3.08, I've heard guys say that no ring and pin set will fit in the pumpkin but I find that hard to believe. I can cough up a couple hundred bucks for a ring and pin set but replacing the transmission to a 5 speed is a little out of my budget right now, even then I'd still want to change out the rear end gears. I'm also aware that when you put in a new gear ratio you need to give it a break in period. I don't know what that looks like, just stick to town and not pull any loads I figure. How long is the break in period? I submit my quarry to you Oh great forum.

 

They are correct, when talking about the 8 lug 3/4 ton rear.

If yours was the 1/2 ton, I believe there is an aftermarket 3.36 gear set available, but it won't fit yours

You won't find decent 8 lug rears with the ratio you want, unless you use a Chevy/GMC rear end from the very later 1970s to middle 80s, but those are wider. Some of those had 3.23/3.21 I've seen in 4wd. Even early 70s to middle 70s 8 lug rears, the lowest number would be 3.73

 

It's either swapping out the entire rear end for another, or updating to an overdrive transmission; or both. Taller tires/wheels will help some. I am Butch/56sedandelivery.

 

so every Apache truck that was a 3/4 ton had the same rear gear ratios in 59? damn. I'm glad I asked before I started tearing things apart. I am grateful for the info

 

4.11 is the best you can get. I'm assuming your truck has the original rear axle. The center sections on 3/4 ton interchange from 47-72. Some late late 1960's have 4.11's rather than the 4.56 your truck should have. Check the ratio before you do anything ,guys used to more modern trucks think 3.55's are screaming at 60 mph. Who knows what gears are in there after all these years.
Swapping is ok but later GM 8 bolt rears are just a bit too wide and the wheels will stick out unless you spend more money on custom wheels.
I drove around for years with a 235 powered truck, 4.11's and 30 inch tall tires. 60 MPH was ok just don't pay attention to the noise under the hood...

 

How do I figure out what gears I got back there? The old farmer just told me they were "extra low". I looked at the outside of the pumpkin (I just took the bed off and had the frame sandblasted) and the pumpkin didn't seem to have any markings.

 

Easy way; Jack up one rear wheel only. Put a chalk mark on the tire and another on the driveshaft where you can see it while you rotate the tire.

turn the tire exactly TWO turns while counting the turns on the driveshaft.

If the shaft turns just a little over 4 turns, but not 4-1/2, you have a 4.11

If it turns just a tick more than 4-1/2 turns, it is 4.56

If it turns a bit over 5 it would be 5.13-ish or whatever ratios were available as an option on 1959
.

 

should be 4.56. I had a 57 single wheel one ton that came with 5.14 gears, so yours isn't really that bad

I put a rear from a 86 suburban in it, with 3.73 gears. But the 454 I swapped in had enough torque to pull those gears with a load...the 235 sure won't, that's why yours has 4.56 gears to begin with!

 

Properly installed and set up rear gears don't need a break in period.

 

Also to be fair you don't need fancy weird offset wheels for the extra wide rear swap. Just narrow the assembly to the right width. It'll cost less then weird wheels and it won't look silly

 

thanks for the heads up guys! I decided to just replace the whole rear end with a 70's gmc or something. It seems a whole hell of a lot cheaper and easier than screwing around with replacing the gears back there

 

Good call, make sure not to gear it to high. Maybe post progress as you do the swap?

 

That's funny about the noise under the hood. I always image how scary a tach would be

 

Get a GM Corporate 14-bolt from the boneyard.

Those can be geared down to 3.42:1.

The one under the GMC Savannah van or the Chevrolet Express van, both of the cab-and-chassis variety should be about the right width, but a tape measure will tell for sure.

I think that they are 63" wms-to-wms.

 

I put a 9" Ford rear end in my '58 Fleetside from a '60 Galaxie. It's 1/4" narrower than the original and it came with 3.10 gears. I took it to the machine shop so they can redrill the axle bolt patern to chevy and that was it.

 

His pattern is 8-on-6-1/2".

No 9" axle has flanges big enough to re-drill to that pattern.

 

I had an 80 chevy C20 pickup with a 3.21 ratio 14 bolt....they're rare, but they do exist.