I have been wondering why Detroit has not released a two speed rear end. Set it up with a lower gear for getting a load moving and a taller gear for highway/unloaded use? Alot of co.s are talking about 6-8 speed transmissions to help with gas mileage. I do not know about you guys but I do not need 4:10 or lower gears all time just when towing. If my rear had higher 3:something for the road and after the load is up to speed. That should cut down on some MPG's? I know alot of rigs used them not sure if they still do though? Any thoughts?
Good question, not sure, maybe cost? I used to drive an old Chevy C-60 when I was a delivery guy years ago and it had a 2-speed rear end, man was that first gear loooow.
All the ones I've ever seen and driven have been air shifted, thats the first problem. I would imagine that one could be designed around a 12v actuator though. Also economical reasons are another big thing. It would be a fairly costly rear end, and these trucks are already sky high. Another problem is the end user.... most people don't even know what a 2speed rear end is, and wouldn't even understand what it's for, nor use it properly. The last problem I can think of is it would only work with a 2wd truck. The designers could probably manage to design a lock out feature that won't allow it to shift when the truck is in 4wd, but you can imagine what would happen if someone shifted it to the wrong matching ratio while in 4wd.
I used to drive an old international flat bed that had a 2 speed rear end. It wasn't air shifted, it was 12V. As for that, it would not be much with the technology available to make it fully automated on an Automatic trans equipped truck. On a stick, well, I would say 1ton dually and up trucks should have it. You sort of expect someone with a truck of that size should be able to drive it.
Look at Gear vendors. I don't have one yet, but gear vendors makes a unit that shifts automatically http://www.gearvendors.com/ Expensive but from what I've heard worth it.
I think the big 3 sold so many trucks to people who really don't need them, they weren't interested in a 2spd rear end. Now with fuel being so high, maybe most of the trucks sold will go to people who need them and the option might be available down the road to get the mpgs up. Just my 2 cents. imp:
