The Stovebolt Site Forums The Shop Area Engine Shop Identifying the rearend

I have a 53 3600 long bed with a 4speed tranny.

I assume the rearedn is an Eaton with a low gear ratio.

How do I know the gear ratio?
How can I identify if this is an Eaton and if so what model?

There is a number stamped on the diff.
8699565 (or could be 3699565)and under that a smaller 344.

Any clues to what this is?

You have an Eaton HO52, judging from your photos in your brake album.
You most likely have a 4.57 ratio, unless the 5.14 ratio was optioned with your truck.
The tooth counts will be stamped on your ring gear.
There should also be a two letter code stamped on your center section.
You can check it Here.

Ghostrider,

Thnaks for the decoder. This sight says that the 3600 came with 4:11. Can that be right?

If I jack up one wheel and turn the wheel one complete turn the driveshaft turns about 2.25 times. What gear ratio would this be?


Thanks again
Rich

Rich,
3600 didn't come with 4.11 in '53. You must have misread...4.11's were 1/2 tons.
What is your axle code??

I never mess around turning shafts and counting revolutions.
I just decipher the axle code or pull the cover. You've probably got a 4.57.

I crawled all over the rearend and the only mark I can find is the number in my post.
I looked over the entire axle when I couldn't find it on the center. There are no other markings that I can see.

Either way, I would still like to get a 4:11 in there as my top speed so far has been about 40 mph. Granny gear is real low 2 maybe 3 MPH. (and that's with my oversized tires)

Thanks for identifying it as an Eaton HO52. That is really all I need to know to try and find a later model 4:11 pumpkin.

Can you tell me where the 2 letter code usually is? Just for kicks I would like to find it.


Rich

Serial number locations

tclederman,

I found the serial number. I can not find the 2 letter code Ghostrider is describing.

Rich

Rich,
The first two letters of the stamped serial number should be the axle code.
My '52 3600 axle code happens to be KG, which is 4.57.
Your '53 code would start with an L.

Hey Rich,

You can find the location for the two letter code Here. It's a 54 chart and the same for 1953. The only difference is the first letter, year "M" changes to an "L" in 1953. The second letter(s) G & H remain the same.

There is a casting number 3969535 for 3/4 & 1 Ton from 47-57 w/ 4.57 ratio, teeth count 32 & 7.

Tom,
So I have the casting number and need to keep looking for the serial number
Thanks
Rich

Try these pictures Rich, should show you what the standard rear axle (Eaton HO52) was in your truck and the locations of the casting and serial numbers. http://www.pbase.com/dennygraham/eaton_ho52
Denny Graham
Sandwich, IL

Thanks Denny
I found them. Not quite so clear as yours but I am able to see that the first 2 letters are LG so I have a Eaton HO52 with 4:57 gears. I think I have found a 1972 pumpkin at eastwestautoparts.com. I bought my brake drums rrom them.
I am going to call now and confirm the details.

Thanks everyone all for your help!
Rich

Glad to help Randy, and you will love the 4.10 gear, it slips right in. I can now cruise at 55mph running about 2500 rpm and I occasionally kick it up to 60 or 65 for a brief sprint. I've even passed a few old people with the new gear.
The down side is if your still running the 216 it's going to seem kind of gutless and I would hate to think about trying to haul a load, but, that's not why I got the old gal, her hauling days are over and she's been put out to pasture as long as she's in my care. The most I haul with it now is a bag of groceries and my "big old wife."
Denny Graham
Sandwich, IL

I think I need to keep an eye out for a 4.11 pumpkin, too. Sounds nice!
Side note - The more I hear you call her your "big old wife," the more I think she looks like this.

I corrected my previous post, it is actually a 4.10 gear in the trucks. The 4.11 and 4.56 were popular ratios available for the cars back in the hot rod days of the 50’s and 60’s.
I had to look for a couple of years to find my gear but it’s worth the effort.

Yeah Dave, my sweetie face taint quite as bad as I make her out to be. She isn’t a Vargas pin up girl any more but on the othere hand she really isn’t a big mama either. I just get to feelin’ like a Wallace Wimple once in a while.
DG

did you determine what the ratio is. by also turned 2.25 times . how fast can you go.