Help with transmission selection

[renobill]

Hi All,
I have a '48 (59 block) coming out of the machine shop soon and am trying to decide on the transmission. I have found several late 80's Ford Ranger manual trans at my local junk yard and would like to know anyone's opinion of them for my build. The Ranger transmissions range in vintage of 1989,1996 and an Explorer 1998 and a Courier 19https://www.fordbarn.com/forum/attachment.php?attachmentid=405179&stc=1&d=1566856 49280.

[frnkeore]

That's a good question! Those transmission are plenty strong and are abundant and cheap.

[Angledrive]

Ratios are all over the map. Big gaps on some from 2nd to 3rd. Do some research on the different ratios. Great trans with 4th being overdrive.

[JSeery]

If you want your car to drive like a truck, use a truck transmission. Trucks, pickups, etc normally use very wide ratio gearing (large differences between one gear and another). That is because they are designed to pull/haul heavy loads. A high performance type of vehicle would more commonly use close ratio gearing (small differences between one gear and another). Then there are all the other in between. You need to select a transmission based on having the gearing you want (or one that is easy to change the gear ratios on), how well it fits in the space available in your application and how easy it is to adapt (are the parts available to make everything fit and work). Need to also keep in mind the clutch/pressure plate setup that will work and how easy it is to adapt the clutch linkage. There are some tried and true approaches with lots of supporting information. The T-5 is one of them, lots of information and parts available, but there are others.

[frnkeore]

They are not a bad trans, check out the specs on them.

Worst case scenario is like a Lincoln Zephyr (2.33, 1.577, 1/1) with a added low first gear and a OD.

Best case is, a close ratio 4 speed, with a OD and with a added 3.40 low first gear, that could win you some "stop light races". The only thing needed is a adapter

But, in any Case, the ratio's are better than the standard '39 box (2.82, 1.604, 1/1).

Frank

[supereal]

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Unless the transmission incorporates overdrive, all are straight through in high gear. If you switch to a non standard transmission, the rear end gearing ratio should be checked and confirmed

[frnkeore]

The M50-D has one of the shorter OD ratio's at .79 - .81, Giving a nice Fwy cruise gear of 2.99 - 3.06, when used with the common 3.78 gear ratio.

So, if your getting 66 mph at 3000 rpm and you use a .8 OD, that takes you to 2400 rpm at the same speed, I think that would be about ideal, with or w/o a street type cam.

[JSeery]

You sure have a different take on gear ratios than I do!!!! I prefer the 2.95 first gear T5s and wouldn't consider a 3.40 as a stop light killer, at least not in my world. But all of this depends on what your goal is. A low rear axle gear is what works for quick acceleration, but if you want a highway curser then that is a different matter. Not many true hot rodders left I guess, so it's not an issue for most.

[frnkeore]

Jerry,
There is only 3.75 mph difference, between a 3.4 and 2.95 gear ratio at 3800 rpm (28.38/24.63), with 28" diameter tires.

But, you have to be very careful, selecting your T5 or, you will wind up with a 3.35, first gear. There is almost no difference for second gear but, the top 3 gears, are a little tighter in the M50-D.

I'm NOT knocking the T-5, I have one but, with it's popularity, the prices have sky rocketed ($500 -1000). You an still find them for ~$300 and less, if the guy isn't up on the prices.

Competition would keep the prices of both trans down.

If only we could get a adapter.

[JSeery]

Originally Posted by frnkeore

Jerry,
There is only 3.75 mph difference, between a 3.4 and 2.95 gear ratio at 3800 rpm (28.38/24.63), with 28" diameter tires.

The mph difference isn't the issue it is the torque, with the 3.4 providing more torque than the 2.95. But the difference is in the rpm change on the engine torque curve when shifting between gears, which is less. Flatheads have a somewhat flat torque curve, so not the biggest issue in the world, but still the close ratio is worth the effort to me. Again, depends on where your interest lie. I run a quick-change, so could play with the rear axle ratio if I wanted to, but I like the 4.11 I currently have setup. It's still is fine on the highway in OD.

[frnkeore]

Jerry,
I found this and I think it will be very useful to anyone that is interested in gear ratio's and how they can effect your driving.

One thing to keep in mind, is that RPM drop, effects the top gears, more than the lower gears because, you have more mechanical leverage in the lower gears but, as you go up in speed, you have less mechanical advantage but, more air and rolling resistance. In racing applications, you typically want a 1000 RPM drop or less, for your top gear.

For a cruiser, the T-5 top gear (.68), will drop your RPM, to give better gas mileage and less noise and wear.

It's hard to get a free lunch if you can't design and build your own trans.

http://www.teammfactory.com/calculat...500/5500/1/0/2

In this case, it's set to compare the T-5 (lower) to the M50-D but, you can just change any of the inputs to what ever gear ratio's and tire size you want. The tire size I picked, was as close to a 8.20 x 15 tire as I could get.

I hope you enjoy using it.

Frank

[Tinker]

39 3 sp?

[frnkeore]

Something to consider for those that want to run hot cams, on the street, is that 3.35, T-5, 1st gear trans. With 4.11 or 4.54 gears, it will get you going better, from a stop, w/o stalling and even with a 4.54 rear gear, you have a final drive gear ratio of 3.09 and still have a very hard pulling car, in 2,3,4th.

I have a '48, F3 truck, with with 4.86 rear end and 33" tires. I put a AOD, behind the 302, giving a final drive ratio of 3.353 and that that lowered my 65 mph, RPM from 3200, to 2200 and much better MPG, on the fwy.

Frank

[frnkeore]

Here's the 39 trans at 5500 & 3800 rpm and the 26 tooth Zephyr.

[frnkeore]

For a light car, say a '27 T, 1500-1800 lb, the -238 trans with 411's and a 400jr cam, would be a real terror. Thinking out loud

Frank

[Tinker]

It's a L head block. If you want to rip it up go with a early hemi or other.


Been driving flatheads for over a few decades. Don't tell me a transmission makes me a 9 sec 1/4 mile. I'll leave that to the guys that do under that.


t5 is a great trans. lot to add.
https://www.jalopyjournal.com/forum/...-links.169265/



.

[glennpm]

Good thread. Good site you found frnkeore.

I ran some different numbers for a 1939 transmission including a Columbia Two-Speed rearend with 25 and 26 tooth Zephyr gears. I set the max RPM at 4,000.

I have a set of the 25 tooth Lincoln Zephyr gears, a Columbia and 3.78 rear in my 32 roadster and love the combination.


Glenn

[JSeery]

Originally Posted by frnkeore

For a light car, say a '27 T, 1500-1800 lb, the -238 trans with 411's and a 400jr cam, would be a real terror. Thinking out loud

Frank

Don't think you would like that combo, truck gears just don't cut it in a high performance application. The hole idea of close ratio gearing is to keep the rpm spread to a minimum. The move to 4 and 5 speed transmissions is for the same reason.

There are some rules of thumb for gear 1st gear to rear axle ratios (there are other factors, these are just starting guidelines).

Drag Racing: 10 to 12
Street Performance: 8 to 9.5

The truck gears

3.35 1st gear X 4.11 rear axle = 13.77
3.35 1st gear X 4.55 rear axle = 15.24

Even with a higher rear axle ratio they have a high final drive ratio

3.35 X 3.78 = 12.7
3.35 X 3.50 = 11.7
3.35 X 3.25 = 10.9

And you still have the gear spread issue.

Now the stock 39 and Zepher gears

Stock 2.82 X 3.78 = 10.7
26T 2.33 X 3.78 = 8.8
25T 2.12 X 3.78 = 8.0

Now the stock 39 and Zepher gears with a 4.11

Stock 2.82 X 4.11 = 11.6
26T 2.33 X 4.11 = 9.6
25T 2.12 X 4.11 = 8.7

[frnkeore]

My point was being able to use a higher RPM cam, on the street and not having to worry about stalling the car, from a stop, in normal traffic. Once your going 20, or so, you won't stall, just bog down.

The other point, with the '27 T, was you would normally, have 13 - 15" wide tires, that's why I change the tire diameter on that application and that low gear, might get you a car length or more, off the line. Hard to make up, especially with the closer ratio's from 2nd through 4th and especially 5th, if you dare

Anyway, as a road racer (Formula Atlantic, 6 yrs), I like that -238 trans.

Remember the old B&M, 4 speed hydro's, especially in A/GS, they had a approx 3.8 first gear and no torque converter.

[rotorwrench]

I don't know of anyone who has ever mated a Mazda M50D series transmission to a flathead so I can't say much. They are a lot longer than many others out there. A T5 is long but they can have the shifter a bit farther forward than some.

The T170 RTS series have been used for a long time but they actually have a center shift top on them. They are a 3+1 shift with overdrive as the 4th gear. They had to get creative to get the 4th gear in there. The ones for the 302 V8 applications have the best overdrive ratio. They were used from 83 through 86 and a few in 87 in F150 pickups & Broncos with both 2WD and 4WD. One with a transfer case is no problem since the tail shaft is generally removed to adapt to the torque tube anyway. Since they were only manufactured for those few years, they are kind or rare now days. Folks keep converting them for model As and such and have been for a long time.