Ram owners. What gear while towing on highway?

I use 6th towing a 12K GVWR 5er on the flat but my truck has 3:73's.

Searching_Ut wrote:
I'm pulling similar weight with the Aisin tranny SRW. I always lock out 6th when towing and sometimes lock out 5th in the hills as the tranny tends to lug itself and hunt fairly bad. Lower gears would be nice when towing but would be a little low when empty running somewhere north of 80 on the freeway. The five useable gears for towing seem adequate, with a good gear for getting up and going when not hauling the 5er

What he said^^^

With 4.30 gearing, I run my Aisin in 6th gear most of time at 60-65 mph without gear hunting. This is somewhere around 1700-1900 engine RPM. Most moderate hills do not trigger a downshift and the steepest passes are carried in 4th. Typically my GCW is 21-23k lbs while carrying a truck camper that is 12.5' tall with my enclosed trailer in tow.

I don't run my truck faster or empty very often, so this works well for me with use of all gears. Average distance per year while loaded is around 10 k miles, so the truck gets plenty of camping.

Brisk wrote:
Thanks guys. I am a little bummed that the truck only came with 3.42s. I think 3.73s would keep me in 6th more.

I wouldn't worry about it too much. You are still putting more torque to the wheels than a 2011 650 lb-ft Cummins with a 3.73.

Ram 2014 2500/3500 6.7L CTD 800 lb-ft @ 1,600 rpm with 68RFE with 3.42 rear ratio
1st gear--3.23: 2,584.00 lb-ft x 3.42 = 8,837.28 lb-ft
2nd gear--1.84: 1,472.00 lb-ft x 3.42 = 5,034.24 lb-ft
3rd gear--1.41: 1,128.00 lb-ft x 3.42 = 3,857.76 lb-ft
4th gear--1.00: 800.00 lb-ft x 3.42 = 2,736.00 lb-ft
5th gear--0.83: 656.00 lb-ft x 3.42 = 2,270.88 lb-ft
6th gear--0.62: 496.00 lb-ft x 3.42 = 1,696.32 lb-ft

Ram 2011 2500/3500 6.7L CTD 650 lb-ft @ 1,600 rpm with 68RFE with 3.73 rear ratio
1st gear--3.23: 2,099.50 lb-ft x 3.73 = 7,831.14 lb-ft
2nd gear--1.84: 1,196.00 lb-ft x 3.73 = 4,461.08 lb-ft
3rd gear--1.41: 916.50 lb-ft x 3.73 = 3,418.55 lb-ft
4th gear--1.00: 650.00 lb-ft x x 3.73 = 2,424.50 lb-ft
5th gear--0.83: 533.00 lb-ft x 3.73 = 2,012.35 lb-ft
6th gear--0.62: 403.00 lb-ft x 3.73 = 1,503.19 lb-ft


Also, being able to run in 6th is not always the best thing for your engine and drivetrain. Being in too high of a gear(even if your engine can handle it) at low rpms with heavy load causes your EGT's to sky rocket because your turbo is boosting to compensate and it also causes high cylinder pressures. It is actually better(for your engine and your fuel economy) to let the gearing do the work and getting your rpms up instead of your turbo working overtime creating heat.

Your 5th gear is still an overdrive gear so don't be afraid to run in it. Most people think that just because you have 6 gears then you always have to run in 6th. Like most veteran truck drivers would tell you "Just because your truck has 18 gears doesn't mean you have to use all of them all the time". I can guarantee you that the last 3-4 gears of that 18 speed probably aren't being used when towing heavy. It is all about being at the right rpm, not the highest gear.

Grit dog wrote:

Brisk wrote:
Thanks guys. I am a little bummed that the truck only came with 3.42s. I think 3.73s would keep me in 6th more.

What did you want? To tow the world in double overdrive?
Yeah the new trucks like yours might do it with deep rear gears, but I would t be bummed. I would t have even asked the question.
I tow or haul in 6th, but my 6th is like your 5th and you don't know much about trucks if you're asking this question, so yes 5th is the proper and preferable gear for what you're doing. Unless you're doing like 90+ with the 5ver behind you, in which case 6th should be well enough into the powerband to run it as well!

To not be so sarcastic, you won't experience any better mileage with running a few hundred rpms less in high gear as opposed to 5th. And it won't hurt the engine either. These motors will pull hard down low, but lugging them and high egts is not what you're after.

You got the best rig out there IMO. When pulling heavy on the flats, pick whatever gear keeps you over about 1800rpms. Going up hill, keep er at 2k rpms plus.

Well.......I was expecting it to pull moderate hills in 6th like my buddy's 2010 ram with the 350hp/650tq motor and a similar trailer did. Turns out he had 4.10s. I am happy with the truck just questioning Rams logic with 3.42 gears. I would have opted for 3.73s or 4.10s so I could run 35" tires too.

Brisk wrote:

Well.......I was expecting it to pull moderate hills in 6th like my buddy's 2010 ram with the 350hp/650tq motor and a similar trailer did. Turns out he had 4.10s. I am happy with the truck just questioning Rams logic with 3.42 gears. I would have opted for 3.73s or 4.10s so I could run 35" tires too.

You are actually putting down more torque at peak with your 3.42 than your buddy with his 4.10 in both 5th and 6th(and the rest of the gears).

Your truck in 6th with 3.42
800 x .62 x 3.42 = 1,696.32 lb-ft (rpm at 65 mph - 1,400)
in 5th
800 x .83 x 3.42 = 2,270.88 lb-ft (rpm at 65 mph - 1,875)

His truck in 6th with 4.10
650 x .62 x 4.10 = 1,652.30 lb-ft (rpm at 65 mph - 1,675)
in 5th
650 x .83 x 4.10 = 2,211.95 lb-ft (rpm at 65 mph - 2,239)

Both his 6th and 5th gear is barely outside Cummins recommended rpm range for efficient towing at 65 mph while your 5th gear puts you right at the optimum rpm range. Just think of your 5th gear as your towing overdrive when you need to be at the right rpm for pulling and your 6th as your empty overdrive to get better fuel economy when you don't.

When I had my 2012 3500 with the 68 tranny, I left the truck in tow/haul mode and let the transmission do its job. It worked fine. Even towing 19K fiver I never had to do anything else. I did have 4:10 gears. I drive the same way with my 2016 3500...

Brisk wrote:

Grit dog wrote:

Brisk wrote:
Thanks guys. I am a little bummed that the truck only came with 3.42s. I think 3.73s would keep me in 6th more.

What did you want? To tow the world in double overdrive?
Yeah the new trucks like yours might do it with deep rear gears, but I would t be bummed. I would t have even asked the question.
I tow or haul in 6th, but my 6th is like your 5th and you don't know much about trucks if you're asking this question, so yes 5th is the proper and preferable gear for what you're doing. Unless you're doing like 90+ with the 5ver behind you, in which case 6th should be well enough into the powerband to run it as well!

To not be so sarcastic, you won't experience any better mileage with running a few hundred rpms less in high gear as opposed to 5th. And it won't hurt the engine either. These motors will pull hard down low, but lugging them and high egts is not what you're after.

You got the best rig out there IMO. When pulling heavy on the flats, pick whatever gear keeps you over about 1800rpms. Going up hill, keep er at 2k rpms plus.

Well.......I was expecting it to pull moderate hills in 6th like my buddy's 2010 ram with the 350hp/650tq motor and a similar trailer did. Turns out he had 4.10s. I am happy with the truck just questioning Rams logic with 3.42 gears. I would have opted for 3.73s or 4.10s so I could run 35" tires too.

3500 has your gears.

Around Mid-North Ontario, I put it in 5th even with my little 8500# bumper pull. There are just too many hills, and when in cruise the downshift to 5th is late and noisy. If I do it manually before the hill, it's fine but that gets tiring fast.

The 3.42 rear works well in 6th when unloaded, even locally in these hills using cruise, and prolly is there for better mileage when unloaded. There's a lot of folks using these things as commuters.

Interesting point about lower exhaust temperatures when running in 5th running at higher rpms, versus using more boost in 6th. Hadn't thought of that. On the positive side, higher exhaust temps because of boost should decrease the need for active regen.

And expect that 6th in cruise might work ok down in the Florida flatlands. We'll see.

That 3:42 helped give me an average of 22.5 mpg on an unloaded trip to Florida and back running 70-80 mph too.

On only one trip I've locked out 6th and that was I-40 into Tennessee. As, said the shifts are a little late sometimes and I can set the cruise easier. Even with my lite trailer.

On a side note. The first new Ram I looked at and noticed the 3:42 on the sticker I asked the salesman about it. He said it must have been a special order, he's never seen one come in geared like that. :S