1965 Chevy 1/2 to Rear End Gear Ratio

[duck457]

I was wondering if anyone has a guide to tell me the rear end gear ratio of a 1965 Chevy 1/2 ton? The vin # is C1545F150363. I emailed the GM Heritage Museum and they only went back to 1977. I know the 3.73 was common to this truck, but the vin # decoders out there do not list rear end specs.

[68gmsee]

Lots of years have passed. There could have been a replacement in the past. Best thing is to remove the cover and count the teeth or look for numbers.

As an example, on my 69, the number was stamped above the passenger side tube covered by 25 years of grime. Check to see if yours is there and if it is you can get a better look at it by removing the tire and then use a wire brush to clean the area off.

[aggie91]

vin # is C1545F150363

Breaks down like this:

C = Chassis Type = 2wd
15 = Series = 1/2 ton longbed 127" wheelbase
4 = Truck Type = pickup
5 = Model Year = 1965
F = Assembly Plant = Flint, MI
150363 = Unit Built = This was the 50,363 truck built that year. Each yr starts at 100,001.

The Vin does not specify the rear end ratio on the 65 or 66 model year. There should be numbers/letters stamped on the axle tube near the center section. You might have to clean it off real good to read them.
The code should be something like this: HA02 17W
it breaks down to this:

HA 65-69 3.73
0217 built February 17th
W by Warren Gear

That rear end example is off a rear end that I bought on craigslist. the gears, carrier, and axles had been swapped before I got it, I just wanted to know what year the housing was for my project.

Hope this helps.

[Captainfab]

The differential is one of the most neglected parts of a vehicle. More than likely the 12 bolt under your '65 could use a oil change. Just pull the cover, drain the oil and have a look and see what gears you have. The tooth count is stamped on the edge of the ring gear. That way, you will also be able to visually check the condition of the inside of your differential and you will know for certain what gears you have. Plus then you will have the peace of mind knowing that your differential is full of fresh oil. It'll only cost you a couple quarts of gear oil and a cover gasket.

[aggie91]

Captain has a good point, a small investment of time and money now would pay off in the long run.

Even if you are not using the truck now, you could pop off the cover and drain the fluid to check out the gears...

[wayparker]

[QUOTE=aggie91;6608295]vin # is C1545F150363

Breaks down like this:

C = Chassis Type = 2wd
15 = Series = 1/2 ton longbed 127" wheelbase
4 = Truck Type = pickup
5 = Model Year = 1965
F = Assembly Plant = Flint, MI
150363 = Unit Built = This was the 50,363 truck built that year. Each yr starts at 100,001.

The Vin does not specify the rear end ratio on the 65 or 66 model year. There should be numbers/letters stamped on the axle tube near the center section. You might have to clean it off real good to read them.
The code should be something like this: HA02 17W
it breaks down to this:

HA 65-69 3.73
0217 built February 17th
W by Warren Gear

That rear end example is off a rear end that I bought on craigslist. the gears, carrier, and axles had been swapped before I got it, I just wanted to know what year the housing was for my project.

Hope this helps.

Hi Karl,
I found this thread in a Google search and wanted to know the resource used to obtain the decoding of the numbers stamped on the axle as well as the VIN. I currently have 65 C10 and wanted to know the steps to validate your information (specifically to DMV). Is the reference a manual that can be purchased? Thanks for the assist.

Wayne

[The Rocknrod]

As an example and how if breaks down:

[The Rocknrod]

Same axle after cleanup, casting date of the center section:

[mattfranklin]

The resurrection of this is old thread is motivating me to check out my two rear axles and see which one I want to focus on.

[vince1]

My truck had a 3.73 which was totally too slow IMO. Astro vans that I had I think were around 3.46 or close to it and they had overdrive transmissions. My truck now has 3.07 gears and I wouldn't want it to be any slower than that, with the 1 to 1 transmission.

The roads must have been so much worse way back when these trucks were new or perhaps they spent most of their life on a farm.

[The Rocknrod]

Originally Posted by vince1

...
The roads must have been so much worse way back when these trucks were new or perhaps they spent most of their life on a farm.

Yes they were and yes they did or at least the were truly utilitarian.

[68Gold/white]

Originally Posted by vince1

My truck had a 3.73 which was totally too slow IMO. Astro vans that I had I think were around 3.46 or close to it and they had overdrive transmissions. My truck now has 3.07 gears and I wouldn't want it to be any slower than that, with the 1 to 1 transmission.

The roads must have been so much worse way back when these trucks were new or perhaps they spent most of their life on a farm.

Pickups back then were not used for purposes anything close to how they are used now, or even in the last 40 years.
Back then they were mostly work oriented. The gear ratio reflected this, and until 1967, a 327 was the largest engine available in a pickup. The 396 became available in 1968, I have one.
The smaller engines needed the gearing to perform the work needed. There wasn’t anyone running up and down the roads, back then, like today, cruise’n in their Cowboy Cadillac....