The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Which gear ratio is best??

Hi, I'm new to the site, just recently brought home a 61 Apache 1/2 ton fleetside. It's got a 283 with a 4 on the floor, which is geared very very low. It will do highway speeds, but the engine has to rev really high, which makes me nervous, considering it's 48 years old. I was told that on these trucks, I can swap out the gears in the rear end with bigger ones, without having to swap out the entire rear end. I don't know what the ratio is right now. But someone said 3.73s (whatever that means) will work well on it. Anyone ever done this? Feedback would be great!

Adam

not sure if the 3.38:1 rear gears that are available for the 55-59 fit the 60-66, but likely - you've probably got 3.90 or 4.11 now .... the problem is they're pretty spendy, you'd do better to find an overdrive trans, which was optional from 55 on, and would be an easy bolt in swap, the 4 speed is only useful for the granny low - if you plan on spending most of your time pickin up hay bales or something

Bill

A 70 C10 sometimes came with a 3.08:1. If you run a V-8, this would be a good hiway gear,
Scott

Where do you intend to use the truck most? For anything but freeway the stock gears are usually fine. Do you have a tach? You say you have a 283. They will generally run 4000+ rpm happy as can be all day long. How tall are your rear tires?

Devin

Like red said, you should have 3.90 gears (provided the rearend is original), with 4.10s optional. The 3.38 from Patrick's will work in your rear, as the 3rd member is the same as the '55-'59 (same rear was used to '62).
Something you may consider is an overdrive trans, either an original style column shifter 3 sped with the Borg-Warner overdrive or a BW T5 or NP A833 (Chevy version) overdirve 4 speed. Taller tires will help, too.

Well, to my knowledge, the rear end is original, but the driveshaft isnt. It was swapped out with the tranny. As for what I plan to use the truck for...generally just cruising around town, with the occasional drive out onto the highway. So I would like it to be fairly comfortable doing higher speeds. I don't have a tach, so I don't know how high it's revving. But, I did drive it at about 120k an hour (60 miles) for 5 hours straight, and it was fine. The tires are 235/75R15. Red, when you said that gears are "spendy", did you mean expensive? Would it actually be cheaper to replace the trans? I didnt know there was such thing as a 4 speed manual with overdrive. I thought about putting in an automatic with overdrive, but have grown to love driving the standard. But honestly, as long as I can get it to do a good highway speed without too much strain on the engine, I'm happy:)

My current truck has 3.55 gears and about the same height rear tires as yours. With a 4 speed manual, 1:1 4th gear, it runs about 2500 down the highway. That's near the top for my 235, but a 283 will run there in its sleep. With the granny 4 speed, I still have all the low-speed grunt I can use.

Devin

Is there a way to find out what my existing gears in the rear end are?

There is a code stamped on the front face of the third member, on the right side. It will consist of 2 letters. MA, MC, MD, MF, and MG are 3.90, MB and ME are 3.38. I don't show a listing for a 4.11 for '61, but the codes for that option for '62 w/4.11 are MT and MU.

What is a "third member"? Dang I got alot to learn!!

On some rear ends, especially older ones, the part that holds the gears is a separate peice from the axle assembly. It bolts in from the front of the housing. the ford 9 inch differential is one of the more common rearends of this style that people are familiar with. Nice thing about the 3rd member rears is that the entire gear carrier can be removed from the axle housing without removing the housing from the vehicle. Makes for much easier service.
Here's a pic of mine. The cleaned off spot on the right side is where the code number is stamped.

Thanks bud, I'll check that out on mine.