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Hey guys, Chris here. First day on the Forum!
I have trawled the web for the last few days with out any real success, so thought the next best option is to sign up, and ask the questions myself.
I have recently purchased a 1965 F250 Twin I-Beam Truck.
The previous owner didn't really maintain the Truck at all.
He noted that the Speedo wasn't working. Stuck my head under, and saw the speedo cable wasn't even hooked up, and the DRIVEN GEAR was missing. Not to worry i thought, easy fix once i get it home.How i was wrong haha.
Would anyone know how many teeth on the driven gear i would need? And associated Part #'s?
I'm sure ive heard of an online calculator to work out the Ratio's....
The previous owner fitted new tires before i took on the truck, which are: 225/75/16
I have attached photos of the actual gearbox, just for clarification to the brains trust.
Greatly appreciate all Input, and advice.
Cheers guys!
Not enough info here yet. Need rear end ratio also. Consider this - for just 4.10 ratio there are a whole page of gears (many duplicates) listed depending on tire sizes. Your tires are radials - they only used bias ply tires at the time of the catalog so you may have to buy a couple or three gears to test to see if you can get closer with one gear or another since a radial to bias conversion may not be super accurate.
Originally Posted by crcooper84
Hey guys, Chris here. First day on the Forum!
I have trawled the web for the last few days with out any real success, so thought the next best option is to sign up, and ask the questions myself.
I have recently purchased a 1965 F250 Twin I-Beam Truck.
The previous owner didn't really maintain the Truck at all.
He noted that the Speedo wasn't working. Stuck my head under, and saw the speedo cable wasn't even hooked up, and the DRIVEN GEAR was missing. Not to worry i thought, easy fix once i get it home.How i was wrong haha.
Would anyone know how many teeth on the driven gear i would need? And associated Part #'s?
I'm sure ive heard of an online calculator to work out the Ratio's....
The previous owner fitted new tires before i took on the truck, which are: 225/75/16
I have attached photos of the actual gearbox, just for clarification to the brains trust.
Greatly appreciate all Input, and advice.
Cheers guys!
Does look a bit ground down on the right side doesn't it? Good eye CD.
Here's a close-up of a typical drive gear and you can see the splines are a consistent height across them and width of each except at the very ends where it tapers off. Might be worth a closer look at that.
Hey mate, thank you for the reply!
Once i posted this, i realized i had missed the Diff Ratio, and the tire height!
I checked the Ratio, believing its in the 3.90 ball park.
Tire height is about 28.5 Inches.
I was afraid that it would be the case of trial and error of a few different Teeth sizes.
Originally Posted by TA455HO
Welcome.
Not enough info here yet. Need rear end ratio also. Consider this - for just 4.10 ratio there are a whole page of gears (many duplicates) listed depending on tire sizes. Your tires are radials - they only used bias ply tires at the time of the catalog so you may have to buy a couple or three gears to test to see if you can get closer with one gear or another since a radial to bias conversion may not be super accurate.
I completely missed this. I just saw the Gear inside, said "that's a win that its still there" and carried on. To excited having this thing in my garage to take note of the finer details.
55HO, that photo definitely shows and proves the one in my gearbox is suspect.
Has the rear differential been swapped out do you think? If not the warranty plate on your door may give us the axle info. 3.89 and 3.92 ratios were 1964 and earlier which used different gears in some cases so I don't want to just start off by giving you bad numbers.
Hey guys I'm in pretty much the same boat. My truck originally came with a 3.50-1 final drive and a 3ontree behind the 352well I swapped out the 3.03 for a T-18, which I know doesn't matter, but also replaced the 3.5 with a 3.7-1 and 31x10.5x15 tires. This puts my speedo about ten mph low at freeway speeds. As in it reads 70 but I'm doing 80. Got any suggestions on which driven gear to try?. Thanks, Dan.
Hey 55HO,
I am really not sure. It all looks very original under there. But who knows after 50 yrs.
I have attached some photos of the Diff Stampings. This might confirm?
I checked the ratio by marking the Drum/Backing Plate, and Yoko, turn the wheels evenly and count rotations of Tailshaft ETC ETC
Originally Posted by TA455HO
Has the rear differential been swapped out do you think? If not the warranty plate on your door may give us the axle info. 3.89 and 3.92 ratios were 1964 and earlier which used different gears in some cases so I don't want to just start off by giving you bad numbers.
Hey guys I'm in pretty much the same boat. My truck originally came with a 3.50-1 final drive and a 3ontree behind the 352well I swapped out the 3.03 for a T-18, which I know doesn't matter, but also replaced the 3.5 with a 3.7-1 and 31x10.5x15 tires. This puts my speedo about ten mph low at freeway speeds. As in it reads 70 but I'm doing 80. Got any suggestions on which driven gear to try?. Thanks, Dan.
I've attached a broad range from 3.00 to 3.70 for you.
