Ram 3500: Gas vs. Diesel Towing

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Today, as I was hauling out my boat at the ramp, I noticed a group of people having a terrible time trying to drag their boat out of the water. Vessel in question was a Tiara 29' cabin cruiser. At the moment I saw them, they were gunning both engine in drive while attempting to pull the trailer in order to help the truck. I went over to inform them that they were at great risk of either frying their raw water impellers, or killing somebody. I'd seen propellers out of water throw a blade at high speed before, and the terrible results.

I was a bit mystified, as I had just hauled out my 32' cruiser using my Ram 3500 4x4 diesel without using either the 4WD or low range gear.

Their truck was a 2013 Ram 3500 Hemi 4x4 single wheel. As I approached, I started looking for common errors or equipment deficiencies that cause a hard pull up a ramp. But what we had there was a properly functioning truck, very good tires, excellent trailer, good positioning on the trailer, and no evidence of extreme incompetence.

I gave them fair warning, which they appreciated, and went about my business, getting food, flushing my engine, and hosing down the boat. When I returned to the ramp area an hour and a half later, they were still attempting to pull the boat out.

They insisted I try to do it myself at the wheel of their truck, and I agreed after making it very clear I would assume no liability for whatever may happen. I jumped in, made sure 4WD was engaged, and transfer case set to low. I leaned into the throttle steadily, until I was nearly at WOT, and never got more than a labored creep out of her, which abruptly ended as the boat came further out of the water. Repeated attempts got the same result. After a while, it was decided to relaunch the boat, and hook the trailer to my truck for the pull.

I made my first attempt in 2WD, high range, and it was a successful attempt. Came right up the ramp with no drama. We then disconnected the trailer, hooked it back up to his truck and he was ready to go.

The owner was deeply vexed. He had just gotten the truck and trailer to be able to pull his boat, and kept giving my truck and his hard looks. He made a vow to "get rid of this _______ thing" and get himself the diesel model.

I guess I was a little vexed myself. I never even looked at the gas model, but I always figured that through engine and drive tuning, they had gotten them nearly equivalent to the diesel models, but nothing could have been further from the truth in this case.

All I know is, this experience hasn't done anything to endear me to the gas 3500.
 
there should be nothing inherently different between gas and diesel. I do have a question for you though: is there any chance that you have a locking rear differential? I have a locker on mine and can always pull my boat out (ok, it's only 24') in 2wd. even on the steepest of ramps; gravel covered, wet, whatever. other than that, perhaps just the extra weight of your truck gives you more traction?
 
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Was the engine revving up and the tires spinning in their truck? If not there might be something wrong with it, other than being a gas truck. It should have been able to squeal the tires in 2wd, if not then something was wrong.
 
I'd be inclined to think something was wrong with the truck and it wasn't producing the power it should. In 4 Low at WOT, you would either be smoking the tires or breaking driveline parts before the engine ran out of power.
 
Originally Posted By: KD0AXS
I'd be inclined to think something was wrong with the truck and it wasn't producing the power it should. In 4 Low at WOT, you would either be smoking the tires or breaking driveline parts before the engine ran out of power.


Agree, especially considering it's on a boat ramp and likely wet.
 
Any full size truck should be able to pull a boat out of the water.especially in 4wd low. Maybe it needs a fuel filter?

My friend Haas a cabin cruiser and his 2wd 1980 Chevy with a 305 and 3.08 gears pulls it right out.
 
Maybe, maybe not. Once, when we used an F350 diesel to try an extract a lift sunk into the dirt, even in low range and 4WD, it only got to the point of the chassis creaking very badly until finally the left rear started hopping. But that truck has almost twice the torque of a Hemi.

This felt exactly like that. Engine didn't feel disabled, no CEL, but it wasn't happening.
 
The diesel has way more low end torque to get it going. It does not sound like the hemi was spinning tires so not a lack of traction just not enough torque.
 
Originally Posted By: spk2000
The diesel has way more low end torque to get it going. It does not sound like the hemi was spinning tires so not a lack of traction just not enough torque.


That was my first thought, but at WOT the hemi should be making decent torque. A modern 3500 hemi, though geared differently, probably puts out more torque than the tractor trailers of old...

My guess is that their use of WOT sheared or overheated the ATF and it wouldnt go as a result. My wife used to have a 4runner auto in the caribbean that would overheat its ATF on steep hills in hot weather. All of a sudden, no traction.... Not a good thing on steep, narrow roads with decent traffic.

I vote for overheated AT.

The interesting test would have been if your rig on their trailer would pull it right out.
 
Sounds like for some reason the transmission was going into limp mode.. But in a new vehicle like that it's highly unlikely but that's my guess.
 
My buddy has a Wellcraft 290 Coastal. Similar in size and weight to a Tiara 29.

He pulls it with a 2005 Ram 2500 with the 5.9 CTD. I've helped him launch his boat numerous times. It always requires 4lo to make it out of the ramp. Some ramps require everything that 5.9 with 4lo has to get out of the water.

I'm not surprised a Hemi was having problems.
 
Makes me wonder how my yukon denali is gonna perform. Pulling the wellcraft nova III with my 94 jeep gc limited 5.2 all wheel drive was ... interesting. 8000lb boat and trailer 28ft long. So I got the 2007 6.2 all wheel drive. We'll see I guess.
 
What would happen if his tailpipe was under water but yours wasn't? Restrictor plate? It'd idle but not go? How much backpressure would that make?
 
I have left trucks idling at the ramp with the tailpipe under water. Doesn't do a thing except make nice bubbles.

I cannot believe that in low range this truck could not just roar out of there. The TC stalls at around 2000 rpm and the Hemi likely makes over 80% of its peak torque at that speed. It would easily spin all 4 tires for sure.

This truck had a serious issue or the brake was on!
 
^^ I wondered the same thing. Parking brake left on perhaps? I have done that many times pulling my boat out. Its amazing how much quicker it is going up the ramp without the parking brake on...!

But having the truck pulling while someone in the boat was leaning on the throttle pushing the trailer and it still didn't move? Something doesn't add up.

Truck had issues, or there was a large submerged rock in front of one of the trailer tires. Between the truck pulling and the boat pushing, there was no lack of power here.
 
Agreed. That's a big boat, but not that big, and it's not like one was trying to pull it out with a 2.3L Ranger. Something was terribly amiss with this particular truck, not that line in general.
 
The Hemi should have had enough torque to pull it up the ramp. Even if it only puts out 300 ft*lbs of torque, there is the advantage of torque multiplication through the drivetrain:
2x for torque converter stall torque ratio
3.5x for 1st gear reduction
2x for transfer case low range
3.55x for axle ratio
Multiply it all together, and there should have been 14910 ft*lbs available to turn the wheels. Something must be seriously wrong somewhere.
This is a case where a run on a chassis dyno may actually be a useful diagnostic.
 
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Any chance some sort of crude traction control system that senses wheel spin and cuts engine output to 'regain' traction?

(like my 2013 Charger had)

Best left 'de-activated' on the dashboard when power is needed despite slippery conditions. (thick winter snow/slush in my case)

Overheated transmission a possibility too.
 
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Even my little Tracker will spin 2/4 in 4 low on dry pavement.
If the guys trans wasn't on fire, then something must've cutting power through the ECU. You can't dump 200-250hp of heat into a dead stall for very long without something going very wrong.
 
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