I have been trying to examine as many possible gearing solutions as I can to determine what setup will work best with a Cummins 4BT, that will give me a tolerable Hi-way RPM, and a decent crawl. Considered a doubler, and while that works off road, and allows me to run relatively tall gears and still have a good crawl, it isn't as versatile on road.
I already have a TH400 from behind a Cummins, but I was really wanting a 4-speed. Well, I just landed a complete Ford setup, with adapter, flywheel, and NP435, and Have been crunching some numbers. Tripped over the Ranger OD listed in Hi-Impact's Site http://www.high-impact.net/transmission_and_gear/rangeroverdrive.htm, and pulled out the calculator, and really like what I see.
What I'm considering is putting an air-shift cylinder on the Ranger, with a shift toggle from an 18 wheeler on the shifter, so that I can split shift it, in effect giving me an 8-speed. A little complicated, but won't really have to use the split's much, and it's a hell of a lot easier than an Eaton 18-speed. These are the gear splits I'll end up with, and they seem pretty uniform, but I'll need to spreadsheet them to see how the RPM matches up at each shift point.
6.68 4.87 3.34 2.43 1.74 1.27 1.00 0.73
Thinking an NP205 t-case, with 5:13's in the axles.
That will give me a Crawl Ratio of about 68:1 which I can live with, and a Hi-way engine speed of about 2000RPM at 65MPH, which is about as fast as I plan on driving this thing, and is right in the Cummins sweet spot.
What am I missing here. This seems like it's a perfect setup, and versatile as hell. It actually seems a bit too perfect. Anyone have any experience with these? As it stands now, this is my final driveline design unless I hear some negatives.
Thanks
Doug
I already have a TH400 from behind a Cummins, but I was really wanting a 4-speed. Well, I just landed a complete Ford setup, with adapter, flywheel, and NP435, and Have been crunching some numbers. Tripped over the Ranger OD listed in Hi-Impact's Site http://www.high-impact.net/transmission_and_gear/rangeroverdrive.htm, and pulled out the calculator, and really like what I see.
What I'm considering is putting an air-shift cylinder on the Ranger, with a shift toggle from an 18 wheeler on the shifter, so that I can split shift it, in effect giving me an 8-speed. A little complicated, but won't really have to use the split's much, and it's a hell of a lot easier than an Eaton 18-speed. These are the gear splits I'll end up with, and they seem pretty uniform, but I'll need to spreadsheet them to see how the RPM matches up at each shift point.
6.68 4.87 3.34 2.43 1.74 1.27 1.00 0.73
Thinking an NP205 t-case, with 5:13's in the axles.
That will give me a Crawl Ratio of about 68:1 which I can live with, and a Hi-way engine speed of about 2000RPM at 65MPH, which is about as fast as I plan on driving this thing, and is right in the Cummins sweet spot.
What am I missing here. This seems like it's a perfect setup, and versatile as hell. It actually seems a bit too perfect. Anyone have any experience with these? As it stands now, this is my final driveline design unless I hear some negatives.
Thanks
Doug