I’ve often wondered why 2 speed differentials, while used on larger trucks, were not implemented in passenger cars. I do know that an aftermarket supplier, Columbia, did make 2 speed rear ends for Ford cars built prior to 1949 and I have seen a 1946 Ford with a Columbia 2 speed rear axle. While the 2 speed axle may not be feasible in a front wheel drive vehicle, it seems to me that in a rear wheel drive, two differential ratios might be beneficial. One higher ratio (lower gearing) would be useful for town or mountain driving and the lower ratio (higher gearing) for flat highway driving.
They are, there are more than a few models, almost always front wheel drive models that utilize two final drive ratios. Here are a few
Some are just basic economy cars some are exotics. But the catch is that the driver doesn’t control which ratio is being used. They are setup so that one ratio is used for maybe gears 1-3 and another is used for gears 4-6.
If the time ever comes that I have to rebuild the old New Process/New Venture transfer case in my Jeep, I understand that the aftermarket can supply parts to modify it to allow use in 2L. There are plenty of times that I wish I could have the benefit of the lower gearing (e.g., pulling a boat up the launch ramp) but don’t necessarily want it locked in 4L. To that effect, it would be neat to accomplish the same with a 2 speed rear end.
I think ‘user control’ is one of the main reasons for not marketing two speed axles.
The other being size and weight.
Except for the few manual transmission buffs out there, very few consumers want to do any thinking for the vehicle these days.
They expect the vehicle to think for itself.
turn the key,
push on the gas to go.
push on the brake to stop.
- A two speed axle would require thinking.
when to up-shift it, when to down-shift it, when to just leave it alone.
So they build more ratios into the transmission for ease of use and saleability.
The weight and size gets transfered to the transmission and probably results in less overall additional.
I feel the motors and transmissions are better and there really is no need for it. All cars and trucks are geared appropriately for the loads they were designed to carry. You and I have a 4Runner with a two speed transfer case which accomplishes the same thing. For vehicles that do tow a lot, the added traction of 4 wd is often worth it. You then get your two speed transfer case.
Ken is right. When trucks and cars had 3 speed transmissions, a two speed axle would give you those needed six speeds. Many cars and trucks have 5and six speeds now with out the two ranges.
The 79-84 Dodge Colt had a two speed input shaft that acted like a two speed rear end.
good memory keith.
I don’t think people nowadays would know what to do with it. If it doesn’t do it for them then forget it.
Trucks have a very special need for an extremely large range of gear ratios that cars don’t need. Prior to 5+ speed transmissions that was accomplished on cars with separate overdrive units attached to the back of the transmission in some cars, in addition to the other methods mentioned above.
Thank you everyone for your comments. I agree that a two speed axle would require thinking that many drivers apparently would rather not do. The Borg-Warner did give more gear ratios–the overdrive could be engaged in either second or high with the three speed transmission. The disadvantage was that until the accelerator was released and the overdrive engaged, the car was in free wheeling. This did not allow for engine braking and many motorists locked out the overdrive in town driving.
I would agree that the multispeed automatic transmissions removed the need for the two speed axle. However, instead of the automatic with its seven or eight speeds, I would like to have a 4 speed manual with a two speed axle–I guess that is the old geezer in me.
The problem with two speed axles is exemplified on the bicycle as you increase the number of primary gears. On an 18 speed with three front chain wheels, you get final drive ratios so close to one another, you essentially have fewer then 12 to 14 speeds that vary significantly.
You then have to up shift by jumping in and out of the hi and low range while down and up shifting primary gears as you accelerate to the next appropriate ratio. (example: 2 high to 3 low) Having discrete gears in the same transmission helps alleviate this redundancy and makes shifting sequential with but one operation. Now accelerating a 4 speed with a two speed axle on a compact driven in traffic this way, would be very tedious and slow. If you weren’t an old geezer before, it would seem so as you drove one.
Nearlly extinct on trucks nowadays as well.
dagosa–truck drivers that I have ridden with did not go through all the speeds–e.g. 2 high to 3 low. The axle ratio was selected for either town driving or for open road driving. Heck, on the old 3 speed manual transmissions I had in my previous cars, on flat ground I would start in first and shift directly to high. On the 1950 one ton Chevrolet pickup that I used to own, I always started in 2nd gear. I used low gear rarely, but it was useful for stretching wire fence. Fourth gear was direct drive. The truck was geared so low that I doubt that it would go over 60 mph. This truck could have used a 2 speed axle.
As I said earlier, there was a 2 speed rear end that was available as an aftermarket for the pre-1949 Fords. The Ford flathead V-8 did not have a lot of low end torque (it didn’t have the torque of the Ford flathead 6 that was offered beginning in 1941). The two speed axle would have been great for trailer towing with the lower speed used when pulling the trailer and the higher speed of the axle used in normal driving.
I did have a hydrostatic drive 14 horsepower garden tractor at one time with a 2 speed axle. I would use the higher speed when mowing. I had a 1 bottom plow for my garden and would use the lower speed for that.
At any rate, I don’t live in the country any more. The Chevrolet pickup and the garden tractor are long gone. I am never aware of which of the many forward speeds my Sienna is using. My mower is a push type rotary mower and I have a one speed rear end for pushing the mower–slow.
The dump truck I use for nursery deliveries has a two speed axle. But, it’s just a button on the shifter of the automatic wand. Not much shifting there. My Kubota L3400hst has three speed ranges for the hydrostatic transmission. Just a pre shift before use. So we do have them. They are just more practically integrated in more easily used autos or cvt transmissions. I still can’t see a practical use vs regular manual transmissions in cars. Guess manufacturers haven’t either. Can you see our Mrs. Driving an Accord or Fusion with one ?
just be glad that the OP isn’t asking for one of these.
While I wouldn’t want a 2 speed axle for split shifts, I would have liked a dual range 4 speed–with cars and engine getting smaller to conform to CAFE standard, we’ll eventually run out of lateral space for shifter movements. IMO, the shift pattern of a 7 speed manual (the clutch pedal kind) of the 2012 Porsche 911 is getting way too wide. A range shift would actually clean things up a bit instead of making things messier. Besides, a dual range 4 speed (8 speed) only needs as many sets of gears as a 5 speed. An 8 speed without any range shift would have more gears, be larger, and heavier.
“. . .just be glad that the OP isn’t asking for one of these. . .”
Chunkyazian–great video. This is exactlhy what I want.
Triedaq may think he wants what is in the video Chunkyazian posted, but he can’t even handle two speeds on a self propelled walk behind lawnmower. His shifting ability is limited to running our electric fan through its three speeds.
Triedag; have you heard of tendonitis ? We old(er) folk become quite susceptible to it. I can 't think of a better way to break the Medicare “bank” then make all of us drive one of “chunky’s” trannys. I can barely text and drive with an auto.
Dagosa–Do what I did. I put switches under the keys of my Underwood #5 typewriter. I fed the switches into a converter that I made from vacuum tubes from a Motorola radio out of a Studebaker. I can text, steer, shift gears and even operate the hand crank windshield wipers. I have the Underwood sitting down on the transmission hump–I reach down to text my messages.
Triedag…You assume wrong that I can type w/o looking at the key board, occasionally/often/all the time. Being a math guy, I envy you literary types for having this skill from birth. Now I can differentiate w/o pencil and paper, but as yet, Apple has not seen fit to promote texting using math symbols alone. I need the auto w/o any extraneous shifting devices. You may be able to reach down to text, I can barely reach down and tie or Velcro my shoes without looking.
You can differentiate w/o paper and pencil? Sweet! When I was taking graduate classes in Mech Eng, I had to type out all my math, or I’d get them wrong. Guess that literary side of me will resonate with me forever.
Although Apple doesn’t do math symbols, I thought their OS run on a Linux based system. There should be LaTeX in there somewhere inside Unix/Linux. If not, perhaps we should push for a LaTeX apps. Then we can type math w/o looking.
"Triedag; have you heard of tendonitis ? We old(er) folk become quite susceptible to it. I can 't think of a better way to break the Medicare “bank” then make all of us drive one of “chunky’s” trannys. "
Not my tranny. I don’t even have a trunk monkey But seriously, shifting gears with non-synchronized transmissions shouldn’t require any effort. It’s all about rev matching.