Towing with 68 RFE Transmission

[EdZacko]

I have read that when towing with the 68RFE trans that is it best to use manual mode and lock out 6th gear tp prevent lugging.
This, I do understand.
The advice above makes no mention of Tow/Haul Mode.

My question is:
If/when I use the Tow /Haul Mode---does this in effect accomplish the same thing or should I still go to manual mode and lock out 6th gear.
I will be towing approx. 14,000 lbs and "enjoying" a few 7% grades.

I recently took delivery on my new trailer which when empty weighs 3500 lbs. I towed it some 400 miles using only Tow/Haul , left the trans set in DRIVEand ley it do its thing. Everything seemed to work weli this way and I had no issues but 3500 is a far cry from 14,000.

Clarification would be appreciated.
Thanks
Eddie

 

[Topzide]

@EdZacko, TH mode is a must when towing along with EB. These trucks learn the way you drive and seem to adjust to the conditions very well. I would say that you need to drive it with the TH and EB on to see how it will handle the weight when towing. You'll always have that option of looking out 6th if needed on how the rpms are doing. It's a learning curve with these trucks with all the power they have! My truck in it's former life towed heavy cross country. Will reach out to my FIL and ask him what they did in the grades encountered in Washington state and will post what was discussed. The towing that I've done with mine, although not as heavy at 7k -10k, has been great and so much better than when towing 5k - 7k with my gasser! Just remember to so the 68RFE some good love on oil and filter changes! If towing heavy a good bit of the time, follow the severe schedule. I'm about to change trans fluid and filters again as I've got 40K on the clock since last change. Fluid still has nice red color, but would rather change out before color would turn. I tend to do things overkill, but feel it's worth it! Enjoy the truck and time spent behind the wheel!

 

[AH64ID]

No reason to lock out 6th, unless it’s hunting in hilly country. The truck is fully capable of towing in 6th, and it will downshift if the load/grade requires it.

TH is a good option, use it when you want to. I generally don’t use it below a 4K trailer but that’s a general thing not an absolute.

See what you like and don’t like.

The locking out top gear is an old, old, holdover.

 

[sag2]

I only tow 5-6k and I just let the truck do its thing. I sometimes use tow haul if its hilly, but sometimes it will not shift to 6th depending on wind and terrain if it is in TH. The mileage seems to be slightly better in 6th, again depending on wind and terrain. You can't really lug this package, it will downshift if it needs to.

 

[EdZacko]

If I misunderstand you all correctly---TH does NOT automatically lock out 6 th gear. So, when i TH ---IF I feel the need to do so I CAN lock out 6th on my own and it will not effect or change whatever TH does for me.

Is this a reasonable line of thought.
For the record, I will simply connect, set TH and EB and just drive and see how it feels and sounds.

Thank you all for the information.
Eddie

 

[Topzide]

Wanted to get back after talking with my FIL. He said they let the truck do its thing! Never locked out a gear up or down grade. They set TH and EB and put in drive. Took several loads cross country with my truck before I got from him and RAM seems to have it figured out with the programming on the shifts. Just need to hook up trailer and go to find out what works the best for you. Even in TH and with Full EB, you can lock out 6th if you want, don't really think that's needed. Just confirm that you have the brake gain set correctly for the load you're towing.

 

[Ozymandias]

48RE to 68RFE was a big leap forward.
Forget everything you knew before - this transmission is smart - and the TH button is there for a reason.

 

[EdZacko]

Again, Thank you all.
These are w wheel electric over hydraulic DISC Brakes.
I will set the Ram controller on HEAVY- EOH and for 14 ,ooo lbs---I should start with a gain of perhaps "+5". Of course I will have to experiment. This is my forst time with such a sophistcated Braking System. Want to get it right.
Eddie

 

[Ozymandias]

You'll love it.

 

[Cummins12V98]

My 11 HO DRW had 3.42’s towing 29k combined. I experimented with 5th and 6th on flat ground. I found exactly the same mpg. I left it in 5th and didn’t drop a gear in the hills like 6th.

In 5th I was turning 1,750 the same as my current DRW in 6th.

 

[EdZacko]

My 11 HO DRW had 3.42’s towing 29k combined. I experimented with 5th and 6th on flat ground. I found exactly the same mpg. I left it in 5th and didn’t drop a gear in the hills like 6th.

In 5th I was turning 1,750 the same as my current DRW in 6th.

At 1750 RPM in 5th what speed were you going up that hill pulling all that weight? And then what speed in 6th at the same rpm. Just curious.
In a recent experience with my 97 5Speed----Towing my 14,000 lb boat, I regularly cruised on the flat in 5th at 60 MPH, until one day the 5th gear nut spun off and I lost fifth gear----quite common for the NV4500------I drove the rest of the trip home, 2000 miles, with the highest gear being 4th and to my surprise I could maintain 60 mph and actually picked up 2 MPG in the process.
I seemed as though trying to maintain speed in 5th was lugging the engine, using more fuel and the lugging caused the nut to come loose.
So now, what does this mean to us with 5th and 6th on these automatics and Tow.

Eddie

 

[EdZacko]

You'll love it.

Ozzie,
I am looking forward to this. I was very happy with the way my 07 5 speed handled my load. This has got to be at least the same thing!

Eddie

 

[AH64ID]

Ozzie,
I am looking forward to this. I was very happy with the way my 07 5 speed handled my load. This has got to be at least the same thing!

Eddie

It will be night and day better. The frame, suspension, and drivetrain are all huge improvements. The 6.7 makes a lot
more power at lower rpms than the 5.9’s did, thanks to the added displacement and VGT.

1750 in 5th on a DRW with stock tires and 3.42’s is ~58 mph. 6th would be 1352, but that’s too slow for 6th in TH.

With DRW tires in 6th 1750 is 75.

What year is your truck? What size tires?

OD does reduce rear wheel torque, so the engine has to make up for it. There is a crossover in rpms vs economy thou. See how it works in TH, and adjust gears as needed. The 6.7 is more efficient at lower rpms under high load.

 

[NIsaacs]

What year is your truck? What size tires?

What exactly is your truck and this trailer? Towing 14k, you will need 3rd or 4 th on a 7% grade.

If you do shift manual at times, be advised, these trucks are so quiet, you will forget and find yourself turning 3 grand or maybe that is just me...

What I have found with my '21 SO, it will pull a house uphill, it just wont quit. But if you want to pass, say a big truck, loaded heavy, you will need a mile of open highway or more. They just don't have the HP, to getter done.

Yet, from a dead stop or a slow speed start on a on ramp, if you give it the go juice, "hard" the high rpm and lower gears are amazing.

 

[EdZacko]

The truck is 2017----the tires are LT285/60 R20E DWL On/Off Road tires.
It is certainly quiet and comfortable. I know what you mean about not noticing speed. It acellerates quite nicely when I need to pass.
The only unknown at present is the HEAVY load--which is why I chose this one.
I will find out soon enough---the week after next.
Looking forward to this,
Thhnaks again
Eddie

 

[monovasia]

I have read that when towing with the 68RFE trans that is it best to use manual mode and lock out 6th gear tp prevent lugging.
This, I do understand.
The advice above makes no mention of Tow/Haul Mode.

My question is:
If/when I use the Tow /Haul Mode---does this in effect accomplish the same thing or should I still go to manual mode and lock out 6th gear.
I will be towing approx. 14,000 lbs and "enjoying" a few 7% grades.

I recently took delivery on my new trailer which when empty weighs 3500 lbs. I towed it some 400 miles using only Tow/Haul , left the trans set in DRIVEand ley it do its thing. Everything seemed to work weli this way and I had no issues but 3500 is a far cry from 14,000.

Clarification would be appreciated.
Thanks
Eddie

I run TH/EB all the time... I remember when I first got the truck and joined here a member said to do this " U will thank me later" was his comment...he was right.... I tow my gooseneck horse trailer all over Colorado... no issues what's so ever with the trans... just maintain the scheduled intervals on everything, stay on top of any ticky tac stuff and they will last forever...

 

[Cummins12V98]

I run TH/EB all the time... I remember when I first got the truck and joined here a member said to do this " U will thank me later" was his comment...he was right.... I tow my gooseneck horse trailer all over Colorado... no issues what's so ever with the trans... just maintain the scheduled intervals on everything, stay on top of any ticky tac stuff and they will last forever...

Sounds like something I would say!

 

[Jim W]

When I was stock a 2008, 6.7L, 3/4T, I never worried about locking out 6th gear just let the truck do its thing. This was with a lighter 5er, I am now on my third unit, and I do tow heavy. I do use gauges on my truck and going up I70 in Colorado I did watch my EGT'S, boost pressure, trans temps on my truck. I do lock out 6th gear when towing in the mountains to allow the engine to run at a faster RPM to bring the EGT's down and kept the Boost below 30 PSI along the with trans temp below 200F, at the sump.

 

[Ozymandias]

Yes that applies to older vehicles good, for the new ones not so much.
They regulate for example EGTs themselves to keep the Emissions system happy at all times.
Also the programming of the 68 has changed a lot during the last 15 years, it will be much more refined then one out of the first year.
The only concern for me would be if it starts to hunt for gears, aside from that I'd leave it do its thing.

 

[NIsaacs]

The only concern for me would be if it starts to hunt for gears, aside from that I'd leave it do its thing.

As long as you don't lift the right foot for whatever reason, then get back in it. It don't know whether to up shift, down shift or do nothing, so it does nothing. Gripes me...