5th Wheel Diesel Towing at What RPMs?

[robkelly]

Originally Posted by Mopar_Earl

I run in tow/haul with the exhaust brake on at all times. I let the "auto"matic do it's thing. I don't lock a gear out unless it started hunting. Or if I'm in a hilly curvy area and wanted to hold some revs when I come in and out of the throttle. 95% of the time I let the trans do it's thing.
But yes, the 3.42s and the Aisin can lug at times with a good load. I'd rather of had 3.73s but not an option from the factory.


Earl

x2

[MontyRV]

Originally Posted by garyp4951

That would be only in a dually, in which the Aisin gives you around 30k max trailer,verses 22k with the 68 trans.

The SRW also has the Aisin option, but still doesn't have big numbers, as the truck itself is limited.
The AS69RC is an option in the SRW 3500. Still better than the 68RFE.



Aisin AS69RC

Aisin AS69RC Transmission Specs & Ratios

The Aisin AS69RC is a medium duty 6 speed automatic transmission offered in the Ram 3500 HD beginning the 2013 model year. It is similar in design to the AS68RC, which was only available in chassis cab Rams mated to the 6.7L Cummins. The AS69RC is one of three transmissions offered beginning the 2013 model year, and comes standard on the High Output version of the 6.7L Cummins only available in 3500 pickups. The transmission is larger and more robust than both the AS68RC and 68RFE.

[Mangort1900]

Aisan units are for the high output Cummins option 68 for standard hp and standard torque.

[kdduke]

I have a 2017 Ram 3500 dieselTurbo with the same setup. I pull a 37 foot Jayco Eagle 321 RSTS and I pull it in the Tow /haul mode always and have my exhaust brake on pretty much all the time. Never had an issue with it lugging. Lots of power, but fuel mileage is also around the 10.5 mpg. Not sure if removing the DEF will improve it or not, but where I live, it's not strictly regulated, yet? I tow mine at 100kms/hr. on cruise.

[Drifter1959]

Keep doing what you're doing. The 3:42 is an unloaded fuel mileage gear. 2000 RPM's is great. I've got the Aisin with the 4:10 and runs higher RPM at cruising speed.

[Edd505]

Originally Posted by NewBlackDak

For that load, you should be engaging Tow/Haul which locks out 6th gear. You should be fine.

BS it does not lock out 6th it changes the shift points. Diesel make power at low RPM, my F350 runs about 1800 at 65. My class 8 operating RMP's were 12-1500 but the was a 13 speed. The ECM will do what it needs to stay in optimal range & RPM. Unless I'm pulling a long grade it stays in normal mode until I see temps starting to rise, then I go tow/haul. I bought my first Super Duty in 1999 and have been driving them since. OP's rig is very close to what I pull 13,000+ As for exhaust break, you don't run it on all the time it's for long steep grades. Want the truck braking on every down hill???

[kdduke]

I have the 3:42 gears in mine, but not the Aisin tranny. I still have a ways for break in, so will see. The Cummings is definitely the way to go. I purchased the Demo Highjacker as well-comfortable towing, and quick slide feature is amazing. Towing through the mountains- with twists and turns and constant climbs and desents, that Turbo and exhaust make towing a dream. Thanks-Drifter!

[John91320]

Guys, what I haven't seen is speaking to the RPM sweet-spot -- right where max torque is. (Recommended by Trailer Life) On my '16 Ram it's right at 1800. My call is best MPG at 1800 locked in 5th, which is about 62 mph. Remember drag goes up quickly from there, so running 1800 in 6th will give lower mileage at higher speed.
And, OBTW, my 2500 has the same rear axle as the 3500, just on coils. While the FCA website says 6000 GAWR, the door sticker says 6500 GAWR for the rear. So, a 2500 CC Short-bed, Cummins, 68RFE tranny, 3.42 gears, a Sidewinder pin box, and I'm pulling a 31RETS Pinnacle. It all works smoothly and I can enjoy tackling all hills.
Be careful out there!

[Mopar_Earl]

Originally Posted by Edd505

BS it does not lock out 6th it changes the shift points. Diesel make power at low RPM, my F350 runs about 1800 at 65. My class 8 operating RMP's were 12-1500 but the was a 13 speed. The ECM will do what it needs to stay in optimal range & RPM. Unless I'm pulling a long grade it stays in normal mode until I see temps starting to rise, then I go tow/haul. I bought my first Super Duty in 1999 and have been driving them since. OP's rig is very close to what I pull 13,000+ As for exhaust break, you don't run it on all the time it's for long steep grades. Want the truck braking on every down hill???

Can't speak for Ford but on Ram you have two exhaust brake settings. On and auto. Auto brakes when you exceed the speed when you let off the throttle or when you apply the brakes. On, it turns on anytime you let off the throttle. So I do run my exhaust all the time empty or towing. I run mostly in auto mode. Depending on the hill I do want the exhaust brake. Also anytime I'm slowing down or need to come to a stop.
Exhaust braking is for all braking. Not just long down hill grades. I just mine all the time empty or towing. In town or on mountains. Definitely decreases brake wear big time. I run tow/haul empty too as I light the shift points and it makes the exhaust brake more aggressive with the higher revs and progressive downshifting.


Earl

[rkymntsno]

Originally Posted by John91320

Guys, what I haven't seen is speaking to the RPM sweet-spot -- right where max torque is. (Recommended by Trailer Life) On my '16 Ram it's right at 1800. My call is best MPG at 1800 locked in 5th, which is about 62 mph. Remember drag goes up quickly from there, so running 1800 in 6th will give lower mileage at higher speed.
And, OBTW, my 2500 has the same rear axle as the 3500, just on coils. While the FCA website says 6000 GAWR, the door sticker says 6500 GAWR for the rear. So, a 2500 CC Short-bed, Cummins, 68RFE tranny, 3.42 gears, a Sidewinder pin box, and I'm pulling a 31RETS Pinnacle. It all works smoothly and I can enjoy tackling all hills.
Be careful out there!

The RPM sweet spot. Mine is between 1800 and 2000, sometimes in 6th, sometimes in 5th, depending on terrain. Speed is between 60 and 70, depending on traffic and the highway. We've only been on two trips, a three hour trip away and a two day trip away and back. So I'm still learning my truck and 5'er and how she pulls. I'm seeing no difference in mpg whether it's in 6th or 5th. Only when I get over 65 it seems to drop a little.

[redley]

Originally Posted by rkymntsno

We're new to towing something this big and heavy and was wondering, at what rpm do you tow at and what gear? The 5th wheel was right at 13,500 lbs. Our TV as you can see below is the CTD 6.7, 6 speed, 3.42 rear axle. At 65 mph, 6th gear, we're at about 1800 rpms. It would downshift to 5 occasionally, but not unnecessarily. It felt like it was "lugging" in 6th, and getting around 10 mpg. I downshifted to 5th gear and left it there the remainder of the trip. It stayed around 2,000 rpms and seemed to like that better. Gas mileage on the "lie-o-meter" continued to say around 10 mpg in 5th, same as 6th gear. All the numbers on the truck remained just about the same, oil pressure, trans temp, oil temp, etc. So am I right in towing around 2000 rpms in 5th gear?

My truck is a Ford F-350 SD 4x4 Diesel 6.0L
hauling a 43’ Jayco North Point RV 17K GVWR.
The trick to hauling a heavy load is to not lug the
motor. The diesel motor is a work horse and loves
to Reve up the tachometer. Just DON’T run the turbo
charger into the red zone. When you approach hills,
lock the Overdrive out until you come over the hill.
Then unlock it on the flats. When you notice the
transmission shifting on the flats, lock the OD out.
When your speed picks up again, engage OD again.

[tazz46]

I have a 34 ft 5ver that is GVWR 11,250
I drive a 2008 GMC 3500 diesel. I use a superchips basic programmer and put it in tow/haul. It changes the shifting patterns and engages an engine brake when going down steep hills. It improves my fuel economy by about 10 to 15% with also adding Airtabs to the back edge of the trailer.

[rkymntsno]

Thanks for all the replies if I haven't said it yet. Great experience shared on this forum. I know with all things, it's a learning curve.

[PMC]

We tow with the set up in my signature and run it all day long at 2000 rpm (Aisin/4:10 combo) and it's been great. Last drive was from MN to WA and we averaged over 10 mpg and I like to run 70mph when I can.

[Whistler]

Great info all!
For me, towing is about the EGT's not the gear or RPM.
I will tow in 6th and manually drop to 5th if the EGT's start to rise, I will even do this when not towing.
My sweet spot for going over a mountain pass is 4th at 1800 to 2000 RPM, this keeps the trans from excessive shifting back and forth from 4th to 5th, keeps the EGT's around 9000 and the speed is 55-60 MPH. Flat roads are 6th with no reason to adjust.
My max towing speed is 65 MPH, no reason to drive any faster.