Hi all, happy Friday. Looking at getting a 5th wheel toy hauler (12.5K GVWR) and wondering what extended RPM range is good for the ol' Cummins.

Can I tow in OD on flats only? At 65mph, in OD, my RPMs are about 17-1800. Is that a good RPM if I tow in OD? At 55mph with OD off, I'm about 2200 but I don't really want to crawl on the open highway.

Also, what speeds do you guys tow at on the open road?

Thanks very much, Mike.

 

I don't tow anything over 5k in OD, just because I don't want 5th gear to fall off. You could safely tow in OD on the flats, just watch your EGT's, and don't jerk it around. I seem to get the best economy/speed mix at about 1900-2100RPM's, but it depends on what I'm towing. I don't pull a travel trailer, just equipment, so I can't really relate to what your pulling. More than anything, watch that pyro gauge!

 

Just throw it in OD and GLH, you should be fine. When you are in a slower speed zone or drivin through a town or climbing a hill, then kick the OD out (if needed) until you get back to the open road. As stated watch your EGT's. If you don't have a pryo, then get one. With just your VA box, you should be fine though.
I don't recommend it, but I've towed a 36' tri-axle 5'er with 3 slide outs in it at about 85mph before while goin up and down the hills. (proffesional driver/closed course )

 

Yeah... Put it in OD, then when your 5th gear nut falls off, call ^him^ to fix it... . Don't lug it in 5th, period.

 

Dude, look at his sig!!!!!!!!!! It says 47RE!!!!!!!!!!!!

 

I thought I had missed something the first time I read this but now it makes good sense

 

Let's all point and laugh at MotorOilMcCall (glad to see it happens to someone else every now and then)

 

yeah atleast eveyone understands when this happens. on some sites you get major flame for not reading something right

 

I use OD to tow my 33' 5th wheel and only turn it off when I'm below 50 mph. Rule of thumb for me, is OD is fine unless you notice the truck constantly shifting in and out of it. In this case, turn it off.

 

Well, I did it. Coming over the Grapevine on I5 was scary painful (35mph). But once I learned to keep the boost up, it did pretty good. As soon as the outside temperature dropped from 103 to under 80 I got some power back. Once I learned to keep the boost up and temps were in the 70s, I could tow in OD as long as I kept the boost up. So needless to say, I'll be shopping for RV275s and finally installing that 4" exhaust that has been sitting in a box in my garage. Hopefully that will help.

Thanks guys, Mike.