Or a modern rear end that has easily swappable gears?
I've been doing some mental truck building, thinking about creating a dd/towing/traveling truck. I'm thinking diesel with the ability to swap rear gears easily. Doesn't have to be on the fly, but a 30 minute job or so.
One gear for when you need to tow and one when the trucks unloaded. I could imagine a single cab diesel with a tall gear could get close to 30 mpg on the freeway. Maybe more if you put effort into it (chip to adjust tune, sloped rear bed shell, etc). When you need to tow, swap it to a shorter one and pull away.
I know there were overdrives in the '60's and quick change rears in the '50's, but they're not going to work stuck under a modern (ish) truck.
-Rob
you mean something like this
http://www.gearvendors.com/
You realize every time you swap gears in a differential, you have to reset the gear lash and pinion depth, right? Plus, if you have a 4x4, you have to change both the front and rear gears.
My point is that swapping gears in under 30 minutes is probably not an option.
RossD
UberDork
3/28/13 11:48 a.m.
Ford 9" with the removable 3rd member?
Sky_Render wrote:
You realize every time you swap gears in a differential, you have to reset the gear lash and pinion depth, right? Plus, if you have a 4x4, you have to change both the front and rear gears.
My point is that swapping gears in under 30 minutes is probably not an option.
I knew it wasn't an "easy" job with a standard rear end. I assumed the quick in a quick change rear meant you didn't have to go through that effort. I know zilch about them, though, so it's probably a wrong assumption.
Some of the ones above seem like viable options. With the 3rd member, you wouldn't have to worry about gear lash and pinion depth, but would have to pop the axles in and out (not hard, but not "simple")? Seems like a decent option and less prone to error (but still effort). Are there specific Ford 9" rears that have it or would any one work? I'm thinking you could save some money by doing some research on all the rear gears Ford offered and hit the junkyard and pick the exact ones you need.
-Rob
rob_lewis wrote:
Sky_Render wrote:
You realize every time you swap gears in a differential, you have to reset the gear lash and pinion depth, right? Plus, if you have a 4x4, you have to change both the front and rear gears.
My point is that swapping gears in under 30 minutes is probably not an option.
I knew it wasn't an "easy" job with a standard rear end. I assumed the quick in a quick change rear meant you didn't have to go through that effort. I know zilch about them, though, so it's probably a wrong assumption.
Some of the ones above seem like viable options. With the 3rd member, you wouldn't have to worry about gear lash and pinion depth, but would have to pop the axles in and out (not hard, but not "simple")? Seems like a decent option and less prone to error (but still effort). Are there specific Ford 9" rears that have it or would any one work? I'm thinking you could save some money by doing some research on all the rear gears Ford offered and hit the junkyard and pick the exact ones you need.
-Rob
a quick change rear, eliminates a lot of what you speak of. see photo:
question is.. could one be adapted to work in a miata?
Given the number of gears and range of ratios in a modern truck's transmission, is there much of a gain here?
As long as low is low enough to get moving with a load, and high is high enough to maximize unladen highway mileage, I don't see where the gains are.
Multispeed rear ends and overdrive boxes seem like band-aids for the era of 2-3 speed gearboxes...
As usual, I've braced myself for being completely wrong.
If this a a 4wd truck I'd go with a TC modded to shift into 2-low, or a dual TC setup.
GameboyRMH wrote:
If this a a 4wd truck I'd go with a TC modded to shift into 2-low, or a dual TC setup.
I was thinking more along these lines as well. You could use an appropriately geared transfer case to give you two overall gear options to run the rest of the gears through so to speak. Even on a 2WD truck, I imagine you could modify a TC to divorce the forward running gear and still use the two gear sets to effect overall gearing. Then there'd be no unbolting or switching of anything mechanical, other than moving a lever in the cab.
Ideally you could end up with a ton of gear for unloaded highway cruising, keeping the engine nearly at idle. Then "low" could be an option for towing.
You could use a 4WD TC as-is in a 2WD truck if it doesn't have a differential inside, or you could mod a TC with a diff to be permanently locked (spool).
A Samurai TC is an example of a diff-less TC, although it would probably turn to a box of metal cornflakes if you tried to move a bigass American truck with one.
I'm under the impression that heavier stuff might have used 2 speed rears until recently, school buses, dump trucks, flatbeds, etc. All too big for a pickup.
I would say Gear Vendors. That way you can gear the truck for towing and use the GV when normal driving.
A quick change rear end may not hold up to towing duty, fine for a race car, not so much for a heavy truck, especially with Diesel power.
gear the thing down low, like you would for towing. When not towing, throw the gearvendor into overdrive and go.
Take 6 or 8 speed. Install in truck. Problem solved.
icaneat50eggs wrote:
you mean something like this
http://www.gearvendors.com/
3 grand buys an awful lot of fuel
