What rear end gear ratios do I have?

['65 chevy lover]

I have a '65 chevy pickup that came with a 283 and Powerglide trans. Does anyone know what rear end gear ratios that most likely came in the rear end? Don't really want to pull off the cover and check but, realize that would be the only way to make sure. Anyone know? Thanks in advance for any help.

[Palf70Step]

I'd say the majority were probably 3.73.

[66Submarine]

Originally Posted by palf70step

i'd say the majority were probably 3.73.

x2

[Bret B]

My '65 had 4:10 but was a 3spd

[LVPhotos]

Jack truck up, spin tire, watch the rotation... drive shaft to tire, if its 3 plus a little =3.73, if 4 plus =4.11 ;p

[60-66]

Look on the passenger side axle tube, it will be stamped with a series of numbers and letters. Stamp will be on the front of the tube somewhere between the backing plate and center section. Tell me what it says and I can positively identify for you

[jtrichard]

Originally Posted by 60-66

Look on the passenger side axle tube, it will be stamped with a series of numbers and letters. Stamp will be on the front of the tube somewhere between the backing plate and center section. Tell me what it says and I can positively identify for you

unless the gears have been changed then it will just tell you what it had from the factory .... I would jack up ONE sine (if its NOT posi) turn the wheel one full turn count the drive shaft turns and divide by 2 and then you know what you have

[Doublelowgranny]

I know this thread is 'old'; I'm new here. I also have a '65 C 10 that came with a 283 & P/Glide. Did you determine what your ratio is / was ?

[Doublelowgranny]

Originally Posted by '65 chevy lover

I have a '65 chevy pickup that came with a 283 and Powerglide trans. Does anyone know what rear end gear ratios that most likely came in the rear end? Don't really want to pull off the cover and check but, realize that would be the only way to make sure. Anyone know? Thanks in advance for any help.

I know this is and old thread; just saw it. I have the same 65 C 10 with a 283 & Powerglide. - Did you determine that you had a 3.73 ?

[The Rocknrod]

If you do what 60-66 said to do in post #6 and post it here someone will tell you. For instance I found that mine shows "WC" on the axle. I was helped out and showed that by looking at the 1964 paperwork on that it is a 3.73:1 rear end.
C14 in this case = our C10

[padresag]

a/t usually had a higher ratio( lower numerically) so one could have a 3:07
RON

[Doublelowgranny]

Originally Posted by The Rocknrod

If you do what 60-66 said to do in post #6 and post it here someone will tell you. For instance I found that mine shows "WC" on the axle. I was helped out and showed that by looking at the 1964 paperwork on that it is a 3.73:1 rear end.
C14 in this case = our C10

Thank you for this.

['65 chevy lover]

Sorry, Doublelowgranny, no I never did find out what it was. Just blew it off.

[rvrfoot]

So no update on this.

[luvbowties]

Originally Posted by Doublelowgranny

I know this thread is 'old'; I'm new here. I also have a '65 C 10 that came with a 283 & P/Glide. Did you determine what your ratio is / was ?

Those gears could've been CHANGED no telling HOW MANY TIMES since the truck left the factory!!!

Do the method that LVPHOTO suggested--up to a point: "Jack truck up, spin tire, watch the rotation... drive shaft to tire". I Intentionally left off the rest of his quote, 'cause not accurate.

Do this. Chock the wheels. Put truck in neutral. Jack one wheel off the ground. Turn the wheel 2 complete turns and count the turns the drive shaft made.

If it takes about 2 and three-quarters turns, it's around a 2.73 gear ratio. If it's a little more than 3, you have 3.08s. If it takes about 3 and a quarter turns of the driveshaft, you have 3.23 or 3.25 gears. Very close to 3 and three-quarter turns, 3.70 or 3.73 gears. A tad more than 4 turns of shaft yields a 4.11:1. etc.

To make it easier to count d'shaft turns more precisely, wrap a pc of masking tape around diameter of shaft, and use a pen to put a short line across tape and in line w/d'shaft. Then make a *pointer you will use to start out pointing to that line. *Use a gas welding rod, sharpen one end to a point, place blunt end into a block of wood that u drilled a hole into to make a snug fit. With wood now sitting on floor, point the sharp end toward the line on the d'shaft-tape. Using a flexible tape, measure the circumference of the shaft. When done spinning, "measure the length of tape" that went by the pointer; divide this length by the diameter. This gives you the ratio: if you get 3.50, then ratio is 3.50:1; if you get 4.11, your ratio is 4.11:1; etc.
Hope this helps a bit. BTW: It is easy to forget to turn wheel twice! If you get answer that reads crazy, like 1.75:1, just multiply by 2: 2X1.75 = 3.50:1--no need to go back and turn again. (Some people just turn once and multiply by 2 to start with and be done with it. But, turning twice gives more nearly accurate answer.)
Sam

[Killer Bee]

Originally Posted by The Rocknrod

If you do what 60-66 said to do in post #6 and post it here someone will tell you. For instance I found that mine shows "WC" on the axle. I was helped out and showed that by looking at the 1964 paperwork on that it is a 3.73:1 rear end.
C14 in this case = our C10

any chance you could post the next page with the '65 C20 codes? pretty please

I know exactly how many times the rear axle gears have been changed in mine, z e r o

I think it's got something in high 4: to low 5:

she's screamin' at anything close to highway speed.. 2 lane country highway that is

[Captainfab]

The most common gear ratio in the C20's was 4.57. It is easy enough to pull the rear cover and have a look. The oil more than likely needs changed anyway. It'll only cost you a couple quarts of gear oil and a cover gasket. Then you will know for sure what gear ratio you have and the satisfaction of having serviced your differential. The differential is one of the most neglected parts of a vehicle.

Originally Posted by Killer Bee

any chance you could post the next page with the '65 C20 codes? pretty please

I know exactly how many times the rear axle gears have been changed in mine, z e r o

I think it's got something in high 4: to low 5:

she's screamin' at anything close to highway speed.. 2 lane country highway that is

[Killer Bee]

Originally Posted by Captainfab

The most common gear ratio in the C20's was 4.57. It is easy enough to pull the rear cover and have a look. The oil more than likely needs changed anyway. It'll only cost you a couple quarts of gear oil and a cover gasket. Then you will know for sure what gear ratio you have and the satisfaction of having serviced your differential. The differential is one of the most neglected parts of a vehicle.

thank you! I think I've posted that and brake fluid components are the most neglected..

great minds think alike

but I certainly agree, it does need servicing.. I was planning a full overhaul later, just curious what code would say..

but 4:57 could be it.. I have 4:56 eaton posi in my 02 gmc but it has 1 over and 33 to 35" tires..

the mating of historical data to an actual vehicle id number or plate is exciting for me though too..

maybe I'll just do a fluid service and inspection for now and see for myself..

thanks again!

[Captainfab]

Even if you do decifer the code stamped on the housing, who knows what may have been changed internally in the past 50+ years.

[Killer Bee]

Dads from the begining and what I learned to drive in about 35 years ago. they're original I'm sure..

but thanks for the boost to put some good gear oil in there for now, great idea..

[vince1]

I get under it and count the turns of the shaft while waiting for the chalk line on the inside of the tire to come back to the same spot.

Changing the fluid is a good idea. When I got mine I had to tow it the short distance home backwards because the pinion was flopping around in there without any bearings left in it. That's what happens when you run them without oil.

[The Rocknrod]

I looked, I did not download it because I didn't need it. I got it here on the forum someplace, it's here...