2018 Ram 6.4l Hemi Towing Issues

[Jversagejr]

I am certain this topic has been posted several times but I am looking for some suggestions to improve the towing on my Ram 2500. I tow a 10000 lb 5th wheel camper and have 3.73 gears and completely stock. The truck tows fine on flat and somewhat flat roads but struggles when pulling hills. I do use the Tow/Haul mode and lock out 5th & 6th overdrive gears.

When going up steeper hills the truck will downshift into 2nd and sometimes 1st gear. When it goes into 1st gear for some reason will not rev into the higher RPM range and seems to lose power almost to the point it as if it is going to stall.

Since upgrading the gearing is out of question due to cost, I am trying to figure out if I need the transmission reprogrammed, a custom tune, a Pedal Commander or a combination. Any advise would be greatly appreciated.

 

[tjfdesmo]

I pulled a toy hauler and went across the scales at over 23K with my '15 6.4, and it didn't struggle like that. Is this happening on winding back roads where you have to travel slowly? Other than 4.56 gears, no bolt-on gizmo is going to make that much of a difference. I thought the 6.4 did pretty darn good, but gassers just don't have the grunt sometimes.

 

[GsRAM]

At 10k loaded trailer weight, your on the cusp of diesel truck territory. As said, nothing other than a gear change is going to make any meaningful difference. Don't waste your money.


However, my trailer is a lot lighter than yours and my truck pulls like a freight train, same gearing as yours. Even with another 4k in trailer weight my truck would not struggle like that.


Something is not right. Your truck will gear down on steep grades, but it should still rev and pull hard. I dont think you have a transmission issue, you have an engine issue. If you have a lot of miles, maybe it needs tuned up or maybe a clogged cat will cause a big drop in power.

How many miles are on your truck?

 

[sandawilliams]

Even with tow/haul on I anticipate the hills ahead and manually downshift to keep the RPM's above 3000. I tow an 8800 lb. travel trailer with another 1500 in the bed over Colorado mountain passes often. Give that a try and see how it works. 6.4 with 3.73's.

 

[tjfdesmo]

Maybe it's going into protection mode/limp mode like the TFL guys harped about on their Ike test?

 

[2003F350]

Yeah I'd make sure the truck is in tip-top shape, because something could be going on.

If there's nothing wrong, then a gear change is all that's really going to make much difference. I've got 4.11's in my PW and it pulls our 7k camper like it isn't even there.

 

[62Blazer]

That does not sound like the truck is running correctly. When you say the truck downshifts to first and still loses engine RPM to the point it sounds like it might stall that is not correct. 10,000 lbs. is a decent size trailer but it is not that big and well under the tow rating of these trucks.......not saying it should pull a mountain pass at 70 mph but it definitely shouldn't be the to the point of feeling like it will stall and physically not be able to pull the grade. Haven't tried out my 6.4 Hemi yet but on my previous truck it was a gas engine only rated at 300 HP and it could always hit the RPM redline in 2nd pulling 9,000 lbs.....can't imagine it every needing 1st gear on the freeway just to make it up the grade.

 

[Jversagejr]

Thanks, this only happens when going up steep hills. On the back winding roads I don’t have a I have seen on other posts where someone mentioned their truck goes into limp mode. This may be what is happening not sure, but I did notice the temps were fine. Truck only has 33k miles and is in good shape. problem. I wish I had 4.10 or 4.56 gears but due to the cost I don’t believe it is possible right know.

 

[Jversagejr]

The truck runs fine on the freeways and regular roads. I only seem to have the problem when I approach a steep grade and it will downshift to the next lower gear, rpms still up around 4 to 5k then and as I continue will downshift again and then continues to lose speed and keeps downshifting to 1st gear. Maybe something needs to be reprogrammed.

 

[RamInfo]

Is that 10k as weighed on a CAT scale, or 10k as stated by the manufacturer?

best,
DG

 

[Firebird]

Gears really are it, unless there's a trans issue somewhere. My 18 6.4 with 3.73 gears and 6 speed, had nowhere near the leverage my current 6.4 with 4.10 gears and 8 speed has

 

[Jversagejr]

The manufacturer states the unloaded weight of 9119. So basically between 10000 or so loaded.

 

[Jversagejr]

Prior to me purchasing the vehicle a few months ago the transmission was replaced under warranty. Could it be possible there is an issue with the new transmission?

 

[crash68]

The manufacturer states the unloaded weight of 9119. So basically between 10000 or so loaded.

You should roll that trailer over the scales whiler fully loaded, your probably pushing closer to 12K. That manufacturer weight is dry, nothing in the trailer, not even propane.

 

[GsRAM]

The 6.4/3.73/6 speed trucks have a 13,600lb tow rating so if he's close to 12k all in, he's pretty much maxed out, which absent of any mechanical issues, explains some of what he's describing.

He's in one ton, Cummins srw territory.

 

[crash68]

The 6.4/3.73/6 speed trucks have a 13,600lb tow rating so if he's close to 12k all in, he's pretty much maxed out, which absent of any mechanical issues, explains some of what he's describing.

He's in one ton, Cummins srw territory.

If he pushing the engine/trans combo to rated max, I wonder if the engine is pulling timing due to low octane fuel? With that amount of weight the Hemi needs to be singing in the high rpms, the CTD will just hum along as it doesn't know those words..lol
@Jversagejr are you running 87 or 89 octane while towing? Might be worth running a few tanks of 89 before trying to scale up the mountains.

 

[Jversagejr]

I am currently running 87 Octane. Have not tried 89 as of yet towing. Do you think a custom tune may help along with the 89 Octane? Also the reason I didn’t get a diesel is I will most likely only tow 10 or so times a year. So the added expense didn’t justify the cost.

 

[tjfdesmo]

I ran 87 octane even grossing 23K. My truck had 4.10s, but there's only a couple hundred RPM difference vs 3.73.

 

[LeeD]

Prior to me purchasing the vehicle a few months ago the transmission was replaced under warranty. Could it be possible there is an issue with the new transmission?

I'd look into that. Maybe it wasn't programmed correctly.

 

[PoMansRam]

If the truck is indeed down shifting all the way to 1st, how fast are you moving at that point? If you are for sure in 1st, the RPMs would be screaming I'd think.

Any crazy electrical loads on the truck while you're towing? Any aftermarket electronics installed? Reason I ask is, if your system voltage drops much below ~14VDC when you're running, all kinds of weird things can happen, such as transmission shifting issues.