How to find out gear ratio in old Ford truck

Hi, I have an old 1964 F-250. I would like to find out what the gear ratio is in the rear end but do not know how to find out. It has a 4 speed in the floor and I love to drive it but much above 50 mph it seems to be winding up quite a bit. Would love to have one more gear or an OD to shift to. I don’t have a tack on it so I don’t know for sure what the RPMs are. On the tag inside the door it says “axle – 24” I don’t have a clue what that means. The Vin tells me when and where it was built and the engine but nothing about the gear ratio. I suspect it is 4:10 or lower cause I shift into 4th about 30 mph and winds pretty fast from there. It has the 292 in it and seems to have lots of power. I don’t plan on making any changes would just like to know.
Thanks for any input.
To keep it tractor related I park it in the same barn with the tractors.
 

Jack up the rear of the truck so both wheels are off the ground. Make a chalk mark on one of the tires, and then make a chalk mark on the driveshaft. Rotate the wheel with the mark one full turn, and count how many revolutions the driveshaft made. This will put you in the ballpark.

Wouldn't surprise me to learn you have a rear gear that is even slower than a 4.10. Might be a 4.56, or even a 5. something.
 
(quoted from post at 15:44:34 09/25/14) Hi, I have an old 1964 F-250. I would like to find out what the gear ratio is in the rear end but do not know how to find out. It has a 4 speed in the floor and I love to drive it but much above 50 mph it seems to be winding up quite a bit. Would love to have one more gear or an OD to shift to. I don’t have a tack on it so I don’t know for sure what the RPMs are. On the tag inside the door it says “axle – 24” I don’t have a clue what that means. The Vin tells me when and where it was built and the engine but nothing about the gear ratio. I suspect it is 4:10 or lower cause I shift into 4th about 30 mph and winds pretty fast from there. It has the 292 in it and seems to have lots of power. I don’t plan on making any changes would just like to know.
Thanks for any input.
To keep it tractor related I park it in the same barn with the tractors.

There should be a tag on the differential that will have either the ratio, or a build code on it. Probably more of a sure thing than door tag. Having said that:

http://www.ford-trucks.com/forums/115597-axle-codes.html

says that is a 3.73, which will indeed wind up a motor with no OD.

Nice truck, but I'm in the same boat w/ my '94 351M and 4.10 rear: The new ones will pull a trailer faster than the old ones will run flat out empty.

Alan
 
{ I hope I have this right it has been a long time] Rotate the rear wheel one full turn and count the driveshaft rotations. Last time I did this it came out to 6.25 ;1 . It was a Chevelle designed for drag racing by Air Flow research. This will get you close to the ratio.
 
you need to count the teeth on the crown and pinion, then divide the pinion # into the crown #.
but it will most likely have the ratio stamped on the crown gear.
and that is not easy, as you have to pull the whole diff. out. where as in a chev just remove the diff cover and there you have it. but just in the 1/2 tons.
 
You know I wondered about that if that would work. If I cant find it out I will give it a try. At about 45 mph it just runs very relaxed. But on roads with a 70 mph limit, where everyone is going near 80 I get my doors blown off. Still a lot of fun to take a slow ride in something old.
 
(quoted from post at 11:10:29 09/25/14) You know I wondered about that if that would work. If I cant find it out I will give it a try. At about 45 mph it just runs very relaxed. But on roads with a 70 mph limit, where everyone is going near 80 I get my doors blown off. Still a lot of fun to take a slow ride in something old.
ne caution: when you jack up both wheels, that is fine if you have some type of posi-traction, but if open differential, then you can easily have an error UNLESS BOTH wheels turn exactly the same amount. I prefer to jack up only on wheel & count driveshaft revolutions as you turn that one wheel TWO revolutions. Using a tape measure around the drive shaft, you can even get the fractional revolution very close.
 
The turn of tires and turn of drive shaft thing (noted below) will only work if you divide the resulting ratio by 2. THis is because the spider gears in the Differential cause the doubling of the shaft speed. I like to turn the tire (assumes a open non positrack differential) 10 turns, and take the number of shaft turns divided by 5.
A posi differential will require both rear tires to be lifted, then the turns ratio is not divided. Jim
 
Get axle code off warrenty tag on door or glove box door and call local Ford dealer or post on here because several have books with codes. If orginal it wiil be rite
 
This infor is for a 1967 F250. Hope it helps.


3.50 (2.3M) Ford (WCC-M) 01
-
4.00 (2.3M) Ford (WCC-N) 02
- 4.11 (3.3M) Ford (WDM-L -V -Z -AB) 05
- 4.57 (3.3M) Ford (WEW-B) 06
- 3.00 (3.05M) Ford 07
- 3.50 (3.3M) Ford (WDM-J -W -T) 08
- 3.70 (3.3M) Ford (WDM-K -U) 09
- 3.25 (3.05M) Ford 10
- 3.50 (3.05M) Ford 11
- 4.11 (3.05) Ford (WCR-M) 12
- 4.57 (3.05M) Ford (WCR-N) 13
- 3.25 (3.3M) Ford (WDM-H -S) 17
- 4.88 (7.4M) Dana 70 22
- 5.13 (7.4M) Dana 70 23
- 4.10 (5.2M) Dana 60 24
- 4.56 (5.2M) Dana 60 25
- 4.83 (5.2M) Dana 60 26
- 4.10 (7.4M) Dana 70 27
- 4.56 (7.4M) Dana 70 28
- 5.87 (7.4M) Dana 70 29
- 3.73 (7.4M) Dana 70 36
- 3.54 (5.2M) Dana 60 37
- 3.73 (5.2M) Dana 60 38
 
on a truck that old, never rely on the door tag unless you're absolutely sure no parts have even been swapped out.

A lot of strange things can happen in 50 years.
 
OK, I'll add me few cents' worth...
Probably the BEST way to tell is counting the teeth - a tedious and oily job at best. Most likely, the truck has a 9-inch rear (standard duty) or a Dana 60 if it is the heavy duty model. Most likely it is a Dana, because Ford didn't make a good heavy duty rear until the '80s when they came out with the 10.25 inch axle.
Most of the axles have a tag that identifies the axle ratio and posi/non posi. The number would look like "4L11" for a 4.11 ratio with limited slip (posi). Unfortunately, given the age of the vehicle, it is unlikely that the tag is still in place. Most likely, the rear has at least had axle bearings replaced by this late date. Many of the "goober mechanics" simply discard tags as having little importance.
The only SURE way to know is to actually count teeth. Sorry.
 
(quoted from post at 17:04:06 09/25/14) OK, I'll add me few cents' worth...
Probably the BEST way to tell is counting the teeth - a tedious and oily job at best. Most likely, the truck has a 9-inch rear (standard duty) or a Dana 60 if it is the heavy duty model. Most likely it is a Dana, because Ford didn't make a good heavy duty rear until the '80s when they came out with the 10.25 inch axle.
Most of the axles have a tag that identifies the axle ratio and posi/non posi. The number would look like "4L11" for a 4.11 ratio with limited slip (posi). Unfortunately, given the age of the vehicle, it is unlikely that the tag is still in place. Most likely, the rear has at least had axle bearings replaced by this late date. Many of the "goober mechanics" simply discard tags as having little importance.
The only SURE way to know is to actually count teeth. Sorry.
disagree. When done carefully, counting wheel & drive shaft revolutions will yield the same ratio number as teeth counting. Done sloppy is about the same as a sloppy tooth count.
 
Should say on the manufacturers tag on the rear end.My 1960 F350 still had it intact.

HTH

Vito
 
That's what I did when I swapped a heavier rear from
a 2wd into my Ford plow truck. I just did it
multiple times to reduce the chances of a mistake.
 
Hello Paul Shuler.

Mark the drive shaft, then mark a tire. One revolution of the tire to 3.5 revolution of the driveshaft its a 350 ratio. If you have a 410 ratio, as you suspect, 4 driveshaft revolutions, + 1/10 of a revolution, to one tire revolution,

Guido.
 
I had a 64 F250 with that same gear ratio with a 223 I6 in it. 60 MPH was about as fast as it could handle. However - it had some real grunt in grannie low when you were pulling something out of the field.
 

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