My Barth has an axle range switch in the dash. Photo attached.

Under what conditions should I use the switch? What is the highest speed advisable in low range?

Trans is AT 646 on a Cummins 6BTA5.9.

Thank you. I'm learning more every minute.

It's all about the RPM. Whatever you run for RPM in high range at highway speed (65MPH), then put it in low range to see what speed it reaches to match that RPM. You then have your answer.

quote:

Originally posted by Moonbeam-Express:
It's all about the RPM. Whatever you run for RPM in high range at highway speed (65MPH), then put it in low range to see what speed it reaches to match that RPM. You then have your answer.

Thanks Corey. When you owned a Barth, did you ever use the axle range switch? Do you have on in your Wanderlodge?

It appears that you have a two speed rear end. Something many trucks had, but never seen one in a RV. Usually was not enough room.

One word of caution. If it is a two speed NEVER shift it going down a mountain as it may slip between gears and you would really be free wheeling down the hill.

quote:

Originally posted by Gary Carter:
It appears that you have a two speed rear end. Something many trucks had, but never seen one in a RV. Usually was not enough room.

One word of caution. If it is a two speed NEVER shift it going down a mountain as it may slip between gears and you would really be free wheeling down the hill.

Pretty cool. I will follow instructions and never shift except at full stop in neutral.

The switch may come in handy because the Cummins is only 190hp.

quote:

Thanks Corey. When you owned a Barth, did you ever use the axle range switch? Do you have on in your Wanderlodge?

I'm pretty sure the only vehicle I've ever owned with a split rear or dual range transmission was a CT90 Honda Trail 40 years ago.

The Wanderlodge has 500HP, but puts out 1450 ft lbs torque at 1200 RPM, so there is hardly a need for any transmission. Since it is equipped with an Allison 6 speed, there is always available power. All at a cost of 7MPG

It would be great if you could take a photo of your switch, your rear end, and your transmission. We could determine if it is indeed a split rear or perhaps an aftermarket overdrive unit. All split rears I've ever seen are air actuated.

Drove a number of school buses while still in HS back in the 50s. Since they were all gas powered they either used vacuumn or electric to shift them. In this case he probably has air available.

Highly doubt it would be a aftermarket OD unit as I am assuming it is a pusher as it is on a spartan chassis and probably has a very short driveshaft.