Changing rear gears to accommodate 1st granny gear?

[Holly100]

My 64 has a granny 4-speed and 3.89 gears. Needless to say, I never use first gear. Has anyone changed the gears and found a way to use 1st gear and then get better rpms on the highway (65-70mph)?

[brute66]

It might be more effective to install a car application transmission to provide you a higher gear ratio. The problem with that approach is the Borg-Warner T-10's, Ford Toploaders and other four speeds can be expensive and not always easy to locate. The toploader is virtually bulletproof and offered two first gear ratios (2.78 wide ratio & 2.32 close ratio). The T-10 was quite strong but I believe it had an aluminum case. Would a 5 speed be out of the question? Just don't use first gear and you would still have a relatively low second gear to take off in.

[banjopicker66]

Which rear end do you have? Ford or Dana?
If it is a Ford 9", then you can easily change your truck's rear end gear ratio for one that requires 1st to be 1st gear.
You will lose the ability to carry any kind of a serious load, though.
A Dana axle gear change presents a greater amount of work than the 9".

You can easily discover which rear axle you have.
From the rear bumper, look at the center of the rear axle.
If there is a removable plate with bolts to hold it in place, then you have a Dana.
If instead there are nuts on the front, then you have a Ford 9". You can exchange the entire center gear section, called the third member, for another one, without having to adjust gear lash. The whole assembly interchanges, and you can get a 2.50, 2.75, 3.00 and more for about $100 - $150.
It usually takes about 2-3 hours to change the third member out for the first time.

Your concerns will be
1. To simply make sure the replacement gears are good and there is no slop in the gearset
and
2. Make sure the axle shaft spline count matches.
Early 9" were 28 spline bearings for the 28 spline axle shafts, and our trucks are usually 28.
The 31 spline was added later to F-150s in the '70s.

[ThinLizzy13]

I have to T18 4 speed in my truck. I'm not sure what yours is, but one thing to keep in mind if it is a T18 is that the 1st gear isn't synchroed. So even if 1st gear were to reach a useful driving speed, you couldn't ever downshift into it. Not that that's something you really do...just pointing it out.

[Holly100]

Thanks for the info. I should have given a little more info. The rear is indeed a 9" with 3.89 gears, 28 spline axles. I believe the stock 4 speed transmission for that year was a T98 and a predecessor to the T18. First gear and reverse are both not synced. I'm not too worried about not being able to downshift into first as I typically don't drive that way anyway. Based on the rpm calculation for 65-70mph I think 3.00 or 3.25 gears would work. The truck is just a cruiser with occasional light loads in the bed, no towing. I'd rather not swap a transmission at this point and just make the truck more driveable with a cheaper pumpkin swap. I guess what I want to know is if the gears I mentioned (3.00 or 3.25) would make 1st year usable and work well with all the others. I don't want to gear it up and find that first still isn't good to start in and that I have to ride the clutch in 2nd gear, like you might with a 3 speed, to get going.

[ThinLizzy13]

I would think it would make it usable. According to my math ( ) I think a 3 rearend would put 1st around 2100 at 10 mph or so.

I'm also planning on doing something along the same lines as you, but I'm going from 4.56 to 3.54. What engine do you have?

[Holly100]

I would think it would make it usable. According to my math ( ) I think a 3 rearend would put 1st around 2100 at 10 mph or so.

I'm also planning on doing something along the same lines as you, but I'm going from 4.56 to 3.54. What engine do you have?

292 Y block. I'm also running 29" tall rear tires.

[jamesdfo]

T-10= Cast Iron Case

SUPER T-10= Aluminum Case

It might be more effective to install a car application transmission to provide you a higher gear ratio. The problem with that approach is the Borg-Warner T-10's, Ford Toploaders and other four speeds can be expensive and not always easy to locate. The toploader is virtually bulletproof and offered two first gear ratios (2.78 wide ratio & 2.32 close ratio). The T-10 was quite strong but I believe it had an aluminum case. Would a 5 speed be out of the question? Just don't use first gear and you would still have a relatively low second gear to take off in.

[brute66]

I've got the 3.25 gear with a C6 and the factory 352. It's the perfect gear in town and out on the freeway. Don't know the height of my rear tires offhand (275 60 15). I'd say either gear would be a good choice just don't expect the 3.25 to be considerably different than the 3.89.

[yellodog]

i ran a t18 with 3.00 gears for years. you still won't use creeper for normal driving but you will have a much nicer driving truck. if you do need to start on a hill or with a load, creeper can be used to get you going.

[bobenhotep]

If you want to swap transmissions I believe you can swap the t18 for a t19 without changing anything. The first gear on the t19 is synchronized, and usually higher than the low gear in the t18. With a 2.75 and a ford t19 you would still have a deeper first gear than what your second gear is now, but would have a really nice highway gear where you might be at around 2000 rpm at 60.

Dan

[LM14]

Don't mess with the gear, go to a Mustang T-5 tranny unless you pull a trailer or haul a load. Very easy to do on a Y-Block. There is usually a large gap between first and second on a granny low tranny. You are not going to end up with what you want. The T-5 is perfect for what you sound like you want.

SPark

[ICEMAN6166]

If you want to swap transmissions I believe you can swap the t18 for a t19 without changing anything. The first gear on the t19 is synchronized, and usually higher than the low gear in the t18. With a 2.75 and a ford t19 you would still have a deeper first gear than what your second gear is now, but would have a really nice highway gear where you might be at around 2000 rpm at 60. Dan

it is both synchro and higher 1st

had one behind a 85 6.9
was nice to roll and shift into 1 rather than complete stop.
was nice in 4x4 too because you could shift from 2-1 without stopping in mud or snow.

[bruceandersson]

My 66 has the 352/t18 combination with 3.06 rear gears if I recall correctly. I've yet to use first gear, but it does handle highway speeds fine and start just fine in second. The creeper first gear transmissions will never work like a typical car 4 speed as there is too steep a difference in gearing between the first and second gears. If you want the 4 speed feel, I'd look at the mid 80's 3 spd OD transmissions out of the 100/150s. Has the same retro long shifter and has a closer set of ratios 1-3. 4th is OD and will drop your engine speed by 30% or so. I put one in my 65 shortie. It was very close to a direct replacement for the three speed.

[jecsd1]

I put an NV4500 in my highboy. Still have the low gear for doing truck stuff but the 5th gear made it a whole new truck on the highway. I can do 75 mph at 2200 rpm

[skidoorulz]

Correct me if I am wrong but going to any other 4 speed will not help when it comes to highway driving to reduce RPM. 4th gear will always be 1 to 1' So going to a higher rear gear is the only way to do what the OP wants to do. Now if you go to a 5 speed it will reduce highway speed RPM because 5th gear is an overdrive gear, but first gear is usually a granny gear in a 5 speed truck transmission so the OP will still have the 1st gear as an unusable gear, at least that is the way my 5 speed pickups were, I always started out in second with 3.54 rear gears with no problems. If starting in first I had to shift before 5 mph

[bruceandersson]

There are 3 speed OD transmissions that have 4 forward speeds but the 4th is OD with a .7 to 1 ratio. These were used in the 80s and were replaced with the 5 speeds since. The nice part of these is that they are bolt in. They fit the bell housing and you don't have to mess with the integral bell housing w/ hydraulic clutch that came on the a lot of the 5 speeds. They are also very inexpensive when compared to the 5 speeds. I've picked up a couple for $150.

[skidoorulz]

There are 3 speed OD transmissions that have 4 forward speeds but the 4th is OD with a .7 to 1 ratio. These were used in the 80s and were replaced with the 5 speeds since. The nice part of these is that they are bolt in. They fit the bell housing and you don't have to mess with the integral bell housing w/ hydraulic clutch that came on the a lot of the 5 speeds. They are also very inexpensive when compared to the 5 speeds. I've picked up a couple for $150.

Are these a truck tranny? And is it a top loader? If so please give more info as to model and such. I may be interested if they truly are a direct bolt in to the Y block bell housing with no modification to the drive shaft and clutch or flywheel.

[unibody madness]

That's the question, will it bolt on to a y block?
I ended up with the t-5, its never as simple as you read on the internet. Cool would be an adapter plate for the y that uses the later longer t-5 as an option

[Holly100]

There are 3 speed OD transmissions that have 4 forward speeds but the 4th is OD with a .7 to 1 ratio. These were used in the 80s and were replaced with the 5 speeds since. The nice part of these is that they are bolt in. They fit the bell housing and you don't have to mess with the integral bell housing w/ hydraulic clutch that came on the a lot of the 5 speeds. They are also very inexpensive when compared to the 5 speeds. I've picked up a couple for $150.

I think you are talking about the T19 that you'll find in 84-85 Ford trucks. I see them most from F250s but wonder if some of that year Broncos had them as well. Like I said, my tranny is the Borg Warner T98 which was before the T18, I believe.