Towing results --again 2500-6.4 3:73

[ronheater70]

So I have been pretty pleased with the towing results and the 3:73 axle.. Towing my new 10k (ish) camper to the beach and the lake and local campgrounds I was very happy with mileage and performance.
This weekend though I towed up 77 into wv and it was one hill after another. I hit second a couple of times and could run 65 in second if I had to at 4300 rpms or so, but I didnt. I was frustrated a few times because I was in third, maintaining speed at 60-65 and it would kick down to second, at which point I would release the gas to upshift to third again, which was equivalent to shooting myself in the foot because I would lose momentum in the process.. But it was holding third fine at 3100-3400 rpms.
But in the big scheme of things that was just a few instances, like maybe 4 times over a 3.5 hour trip.

So A while back I contemplated going to 4:56, even before I towed this new camper, and some folks chimed in to at least try the 3:73 first..so Im still pretty happy with the 3:73. At no time was I not able to maintain the speed limit twoing 10K (ish) pounds along the hilly interstate.. It just depends on how much RPM I want to pull.

I think If I do swap, I will just go to 4:10 and not need to swap the front carrier. I know its a small change but I feel it really needs VERY little help to stay out of second and pull a tad longer in 4th. Or I may just let it be and let the tranny do its job. That motor sounds like magic spinning at 4K though!

 

[tjfdesmo]

What was your MPG?

 

[ronheater70]

Going to the beach, and lake, and around home, I have been consistently 10-10.5 or so. Honestly, this weekend, I didnt pay much attention..I think quick guesswork had me in the 9 or so..

 

[McBroom]

The 3.73’s are fine. A lot of big 18 wheelers use 3.55 gears and maintain just fine.
If you were to swap to 4.10’s your rpms are gonna be higher towing or not. I’ve seen videos about the 6.4 n 6 speed 3.73’s tranny towing and by the sounds of what you’re saying it’s running perfectly as designed. I don’t believe you need to change the gearing at all. Rpms in the 4-4800K range is where max torque n HP are. So just let the motor work.
JMHO and .10 worth


I Love my 18 Ram 2500HD 4x4 CC
Blue Streak Pearl off-road package

 

[22hemi13]

The 3.73’s are fine. A lot of big 18 wheelers use 3.55 gears and maintain just fine.
If you were to swap to 4.10’s your rpms are gonna be higher towing or not. I’ve seen videos about the 6.4 n 6 speed 3.73’s tranny towing and by the sounds of what you’re saying it’s running perfectly as designed. I don’t believe you need to change the gearing at all. Rpms in the 4-4800K range is where max torque n HP are. So just let the motor work.
JMHO and .10 worth


I Love my 18 Ram 2500HD 4x4 CC
Blue Streak Pearl off-road package

Heck yeah. That motors suppose to work. Lock out gears if you need to. But sounds like she performed as she should.

 

[McBroom]

I’d be tickled ****less for those results. Ohh wait I am. I love hearing stories about how Damn Awesome our 6.4 HD Trucks are!!!


I Love my 18 Ram 2500HD 4x4 CC
Blue Streak Pearl off-road package

 

[ronheater70]

Honestly, my issue is seemingly just the mental aspects of it.. The fact it hit second gear on the interstate just annoys the heck out of me, but the reality is it was still only tacking 4k-4.5K and maintaining 65 MPH (if I wanted).. BUT I am paying to have a new rear diff put in this thing in the winter time because Ram wont fix my increasingly noisy rear diff whine..So then the issue becomes Im already spending 1/2 of what I need to do a re-gear to lower gears, so its kinda like that Hmmmmm Moment. But the fact is, that with 5 adults in the truck, the 8' bed nearly full and the AC running. the 3:73 performance was good towing that weight

 

[MADDOG]

Have you tried putting the trans in manual mode, and 3rd gear, as you approach the hills?

 

[kiloRAM]

I was wonderfully surprised how well my 6.4 with 3.73:1 did. I read tons of posts on this forum where the posters were talking crap about the 3:73 and I was scared I ordered the wrong truck. In reality, during a 14 hour round trip I pulled about a 10k trailer, had stuff in back of truck, with three adults and; I was not only able to maintain speed going up hill, I was able to accelerate up to speed limit. A couple times going up big hills, the truck down-shifted to really high RPMs which I was not a fan of, but overall, my 6.4 performed like champ. I was totally impressed.

To the contrary, my old 1500 w/ 5.7 and 3.92 (I think) basically croaked going up those same hills pulling a much lighter trailer. It slowed to 30 - 35 uphill (while 6.4 accelerated or maintained speed limit going up hill).

Oh, almost forgot... I got just under 8 mpg pulling approx 10k, with stuff in back, 3 adults, and a great big parachute attached to the trailer I was pulling.

 

[RLJ10X]

I have the 5.7 with 4.10s and a 545RFE. Great combo.

I know you have a lot more muscle under the hood, but I don't pull anywhere near 10,000 pounds, either.

If I had to take the rear end apart, I know I'd put 4.10s in it.

 

[ronheater70]

Yea, this trip was the real test mule.. I don't see much terrain any more demanding than what I was on.. Yea it revved high a few times, but I never had the feeling I couldn't maintain speed, or even accelerate as was posted above.

So yea If Im paying to have a rear end put in, Id like to put the 4:10 in, however its 4x4 so Im now asking do I essentially want to double the price for an easier time to this one campground, when I feel like it performs very adequately on all the other trips.

Oh yea, I did put in 3rd manually once, it did help a little!

 

[22hemi13]

The gassers make their power up high. So what seems like high rpm really is where the engine needs to be to make the power. It’s like it’s singing A song to you lol

 

[wyo2track]

So I have been pretty pleased with the towing results and the 3:73 axle.. Towing my new 10k (ish) camper to the beach and the lake and local campgrounds I was very happy with mileage and performance.
This weekend though I towed up 77 into wv and it was one hill after another. I hit second a couple of times and could run 65 in second if I had to at 4300 rpms or so, but I didnt. I was frustrated a few times because I was in third, maintaining speed at 60-65 and it would kick down to second, at which point I would release the gas to upshift to third again, which was equivalent to shooting myself in the foot because I would lose momentum in the process.. But it was holding third fine at 3100-3400 rpms.
But in the big scheme of things that was just a few instances, like maybe 4 times over a 3.5 hour trip.

So A while back I contemplated going to 4:56, even before I towed this new camper, and some folks chimed in to at least try the 3:73 first..so Im still pretty happy with the 3:73. At no time was I not able to maintain the speed limit twoing 10K (ish) pounds along the hilly interstate.. It just depends on how much RPM I want to pull.

I think If I do swap, I will just go to 4:10 and not need to swap the front carrier. I know its a small change but I feel it really needs VERY little help to stay out of second and pull a tad longer in 4th. Or I may just let it be and let the tranny do its job. That motor sounds like magic spinning at 4K though!

For what its worth, I have 4.10's and can say that at my altitude of 7200' and pulling my 6500# TT up a true 6% grade that 3rd gear at 68-70 mph, which is right in the breadbasket of 4000-4200 rpm of torque, will not hold speed and I have to downshift to 2nd and hang around 65 mph just so I'm not up against the rev limiter. I know I'm losing a little more HP at altitude than say someone at 3000', but I don't see such a small change of 3.73 to 4.10's keeping you out of 2nd gear unless those grades your pulling are significantly less than 6%. Just my 2 cents. Using 2nd for me is usually such a small % of drive time that I don't care. It is what it is. Glad to hear your really liking your truck and these 6.4's do sound good revved up!

 

[sandawilliams]

I tow about 8800 lbs. With another 1500 in the bed with the atv, generator, and blocks. I have went over the highest and steepest passes in the west and never a problem. Sometimes in 1st gear but no worries.
6.4 with 3.73's.

 

[ronheater70]

For what its worth, I have 4.10's and can say that at my altitude of 7200' and pulling my 6500# TT up a true 6% grade that 3rd gear at 68-70 mph, which is right in the breadbasket of 4000-4200 rpm of torque, will not hold speed and I have to downshift to 2nd and hang around 65 mph just so I'm not up against the rev limiter. I know I'm losing a little more HP at altitude than say someone at 3000', but I don't see such a small change of 3.73 to 4.10's keeping you out of 2nd gear unless those grades your pulling are significantly less than 6%. Just my 2 cents. Using 2nd for me is usually such a small % of drive time that I don't care. It is what it is. Glad to hear your really liking your truck and these 6.4's do sound good revved up!

Well one section was probably 6 to 7 percent and about 4 miles long. I pulled it mostly in third at 65.. Im at about 3500 rpms or so at 65 in third..Amazing th altitude makes that much of a difference. i think I could have pulled it all in third if I drove it just a bit better and chose my lanes to compensate for slower trucks.

 

[U&A]

Tour not going to have a HUGE jump in RPMs going to 4.56’. Do it. The difference between 3.73 and 4:10 is negligible.

I say go 4:56...... but im going to possibly change the carrier in the front diff of mine and go 4.88’s.


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[mtofell]

I'm pulling 11K or a hair more and 2nd gear is my friend. The only ***** is when I can't hold it and the truck tweaks out in first. I'd have no need to want a re-gear if not for the mile gap between first and second. And I know the gap will still be there but it will be a bit less noticeable and at a lower speed so I'll have a better chance to hold 2nd.

I was just out on a steep-ish mountain road that was curvy and in pretty poor shape. Poor enough shape that I couldn't go much over 40. So, many times the truck would SLAM back into first. All I can say is thank god for my lifetime warranty. If this was on my dime I'd probably have sold it in by now because with every "slam" up a steep hill with an 11K 5th wheel behind me I think something is going to fall off the truck but she keeps on going. As long as I can hold 2nd the Hemi is a total beast. I've pulled 6% grades at altitude maintaining 60-65 fairly easily. It's just that 1-2 gap that sucks ass.

 

[Ratket]

It all comes down to the terrain you are towing in. The terrain that I used to tow in was steep, often in 2nd gear and trying to stay out of peoples way, when I had my 6.4 I was really tempted to go to 4.88”s just so I could pull those hills in 3rd and have more left if needed. Not like I ever got to see 6th whole towing anyways and when empty, 4.88 would yield better mileage due to the fact that mds would activate much easier and yield better mileage. But hey if it works for you than that is awesome!!

 

[U&A]

Exactly right!!!

if you re-gear to 488 you have a much better chance of holding 3rd gear giving you much more leverage (capabilities) and “comfort” while towing.


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[ronheater70]

But going to 4:88 wouldnt you then be running about 4500 RPM in third gear at highway speeds instead of second gear?
So your pulling roughly the same rpms I would think, then second gear becomes kind of useless, not that you would need it much!