2 Speed rearend

chili · Mar 30, 2007

I wonder if it is possible and cost effective for the big three to make a 2 Speed rearend with a switch for trucks. One for everyday driving and one for towing. This would save fuel when you not towing something. Is this possible?

QRTRHRS · Mar 30, 2007

I suppose it would be possible but hardly cost effective. Any current two speed rear out there now is way to large for a pickup.

US Gear and Gearvendors make two speed auxilary trannies that you can add to your pickup.

hudr · Mar 30, 2007

Used to be a lot of 2 speed rearends on 3 ton trucks and what not. They were mostly operated by an electric solenoid. I have one on my 86 F700 dump truck. I don't remember ever seeing one on a light duty truck (1 ton and under). They seem to have gone out of vogue in the past couple of decades. I think a lot of it would have to do w/ driver education. As a society, we seem to be gravitating towards equipment we don't have to think about to operate. This is not necessarily a bad thing. Put the average 21 year old in a truck w/ an electric switch on the shifter. If he/she does happen to know how to drive a manual, will he/she understand the concept of splitting gears when loaded? The trucking industry has for years tried to come up w/ a transmission that "anybody" could drive. Once again, this is not necessarily bad. Less attention on the equipment, more attention on the job.
Hmmmm, before this officially turns into a rant....
I don't know if it would be cost effective, but it is definitely possible. There are a few 2 speed aux trans on the market that allow you to go from direct to overdrive or direct to underdrive, like this one..V2OD Overdrives

cp1969 · Mar 30, 2007

You already have this option, at no cost. If you have a 6 speed, tow in 5th. Most automatics have a tow mode which locks out any overdrive function.

KICK · Mar 31, 2007

pretty much what HUDr said.

You'd have to train somebody how to drive the thing.

I had an F600 with the 5 speed with the 2 speed rear. gave you nine useable gears in an underpowered vehicle. PITA to drive in traffic.

had a different 600 with an Allison automatic, an AT 540 to be exact.

guess which one was more drivable?

Builder · Mar 31, 2007

Used to have a '71 International "1510" dumptruck with a 2 speed rear. 'bout the size of an F-450/550. Very nice truck for its' time. The 2 speed rear in such a small truck (GVWR was ~15,000) really helped the 345 V-8 a lot when heavily loaded. It ran all the way up until the late 80's.

herringchoker · Apr 1, 2007

Like hudr said.
I drove a lot of those way back when. Last one was a 1975 F750. With too much crushed stone in the dump box and a triaxle trailer with a 6 ton backhoe behind, I needed every one of those 9 gears.

hudr · Apr 2, 2007

CP1969, In reference to already having this feature, he probably doesn't. An overdrive doesn't change the final drive ratio. Getting the load started, and being able to run with traffic loaded is mostly a function of the ratio in the rear end. Dropping a gear at highway speed is ok for hills, but starting the load rolling will be easier with a 5.30 rear end ratio than with a 3.73 ratio.