Unable to pull trailer up hill?

[RedRam55]

Yesterday I had the dump trailer loaded and backed down the driveway. When I tried to go forward, the truck would not move. It acted like the torque converter was holding in stall speed with the parking brake on. The driveway is dirt but the tires were not spinning. I turned off the traction control but the same result. I put it in 4 WD low and it went up the hill slipping the front and rear tires a little on the way up.

This is a 2017, 2500 Laramie with the Cummins. 68RFE trans (I think that is the right amount of numbers and letters). It has just over 5,000 miles.

I thought these were torque monsters and I would have expected the rear tires to be breaking loose with the traction control off.

The trailer was about 14,000 pounds and the driveway is probably 7% grade. Admittedly it is a heavy trailer on a pretty good grade, but I was expecting tires to spin at some point.

Today, with the truck empty, no trailer, I floored it on the dirt road. No tire spin with the traction control on or off. After about 50 ft the power came on and the tires began to break loose.

So, is this the normal way for these trucks?

 

[FCA Master]

Definitely not normal. However, I need a little more info. Was the truck warm? Did it move at all? Was tow/haul on?

Keep in mind that the LR clutch is only applied until 150 RPM tailshaft speed (approx. 8 MPH) and then the sprag clutch takes over. The sprag is weak and has a plastic cage (definitely a point that can be improved).

 

[RedRam55]

It was warm. I just arrived home after towing the trailer from the quarry. It was about a 2 mile slower drive in the dirt road then a few more minutes idling.

Tow / Haul was on. After about 5-7 seconds of holding about 2,000 RPM, it slowly started to move but I mean real slow. That is when I figured why tax it any harder and used 4-low.

 

[yillbs]

I'm not an expert, but I bet someone else is. It sounds like you're getting a 1:1 ratio on your torque converter, I.E, it needs to be replaced. When you're at a dead standstill and you attempt to move up the hill, you have zero momentum. Are you getting a running start at all? I mean, do you move forward before you go up, or is it just up up and up? Regardless of any of that, if you're completely empty and it's still not ripping lose with no trailer, it's just another diagnosis for the same issue with the TQ converter. Call up the dealer, and schedule an appointment.

 

[sandawilliams]

It was warm. I just arrived home after towing the trailer from the quarry. It was about a 2 mile slower drive in the dirt road then a few more minutes idling.

Tow / Haul was on. After about 5-7 seconds of holding about 2,000 RPM, it slowly started to move but I mean real slow. That is when I figured why tax it any harder and used 4-low.

There has been a few times over the years that I was towing heavy and the same thing has happened. Starting out on a steep hill with a heavy load and too high a gear ratio will cause this. I have driven 4X4 trucks the last 30 years just for this reason. 4Low will pull stumps and will get you going anywhere. This has happened on my chevy's, gmc's, fords and now Rams.

 

[ronheater70]

You sure it's not that hill hold feature working. Sometimes it take a little throttle to overcome it and get the brake to release

 

[mtofell]

4lo has just a crazy amount of torque with these trucks. I find myself having a hard time keeping the truck sitting still at lights. The truck will override the brakes unless I really stomp on them. Granted, a 14K trailer and an incline is a lot of resistance but it sounds like something is not right.

 

[sandawilliams]

In years past people would complain about automatic transmissions that would not pull away from a stop if there was a wooden 4X4 in front of each wheel. Many used that as a way to talk **** about automatics. Nothing has changed when it comes to launching heavy loads with automatics.

 

[SouthTexan]

Sounds like you have a torque converter that is on the high side of the rated stall speed bell curve. The rated stall speed of the torque converters attached to the Cummins trucks is already too high in my opinion and if you have one that is even higher then that then it makes matters worse especially when towing heavy loads.

When you are unloaded trying to go up your driveway, can your truck pull you up the driveway without giving it any throttle?

 

[RedRam55]

There was no running start. I backed down the driveway to dump. I needed to go forward about 10 feet. I put it in drive and pushed the pedal down. After holding ALL the way down for 5-7 seconds with the engine at about 2K, it slowly started to move. I put it in 4 low and it was able to get right up the hill.

On level ground with the trailer loaded it will spin the tires under acceleration. I had that happen when I started from a stop sign making a left turn with the trailer loaded.

On the flat dirt road it would not spin unloaded until the turbo kicked in, then it was breaking loose.....at about 20 mph and up.

I may have missed it, but I don't think my truck has a hill assist. My Jeep does....but I have not seen that anywhere in this truck.

It acted like it was trying to start up the hill in 2nd or 3rd. reminded me of a Ford with their 2nd gear feature to avoid spinning the tires in snow, or if you were being stopped by the traction control.

I don't know....For you guys with the similar truck, on a flat road, will it spin (do a burnout). With the "fly by wire" throttle, it is not what your foot is doing, it is what the computer will let the engine do.

 

[MasonD21]

This is actually fairly normal... minus the 2krpm part. At 1,000-1,500 RPM, your turbos are just starting to spool up, building boost. If the engine is not spinning enough to create enough exhaust gas to spool the turbo on the exhaust side, it can't pull/build enough boost at the crank. And with that load, with the weight of the truck, on that kind of a hill, I would expect a long delay til the wheels started rolling, to get the RPMs to climb and create boost.

BUT... 2,000 RPM is definitely a concern. Shouldn't take 5-7 seconds to spool the turbos at that.

 

[WilliamS]

From a dead stop aimed up 7% in high gear sounds about right to me. At 0 mph and not spinning at all so your not building RPMs to get past the stall it sounds accurate. 4low is so highly geared its almost at the stall at no mph already so between that and the torque multiplication getting the load moving makes sense.

What does surprise me and unless i missed it, how didnt the rear tires break free when you were powering up and not moving?

 

[jaflowers]

I don't have and haven't driven a newer Cummins truck but I've driven a lot of my families farm Rams (2500/3500) and my own gas Ram. If you have disengaged the traction control and stomp on it on a dirt road you will break free, really seriously. If your truck isn't doing that then it needs to go into a dealer for service. I've watched my uncles hook up to 30,000+ pound loads many times, nursery farm, with their Rams and drag the trailers like it was nothing up mountains/through dirt road fields.....pretty much anywhere they wanted to go. Something isn't right with yours.

 

[RedRam55]

I suppose it sounds a little normal, except the breaking tires loose. I figured it would have done that. I am going for another load next week. I am going to testing and see exactly what is going on as far as RPM and so on so I can have a good accounting for the service writer. Maybe it was just too heavy to get it in the power range. I am glad there was a low range to get me up the hill.

I would have expected the tires to really break loose from a stop unloaded. Once the turbo got into the deal, the tires did break loose. I don't know.....my first diesel. I am not used to the power ranges. To me, this trans lugs a lot and takes quite a bit of pedal to get it to downshift, but I have read quite a few other threads where this too seems normal.

Thanks for the input guys.

 

[MN-Ram]

If your truck has low miles, the drive train is still learning. Probably do not want to start from a dead stop on hill like that, with that heavy of a load either way though. You’re lucky you didn’t spin the tires and bury the rear end in the gravel. That would have really sucked.

 

[RedRam55]

I would have stopped way before getting buried...I have a theory. If you can get out without a tow truck, you are not stuck, only temporarily detained.

Not sure how I could avoid starting from a dead stop on a hill like that except not backing down the hill to begin with. It really was not too big of an issue with the 4WD low. It just went right back up the hill. I was just surprised at the low end torque (or lack thereof) from a stop.

It was probably too much of a load/grade for regular range, and maybe the rear would not spin because of the weight on the rear.

I will see how it does on the next load. On level ground with that load it does spin the rear to the point I have to stay off the throttle a little or it leaves black stripes. I think it was just a bad combination to try and get the truck to do without using low.

 

[BWL]

Watch your tranny temps while this is happening and check your fluid for burning. If it's slipping you'll heat it right up and burn the fluid. If so it's a Trans problem.

 

[rcmedic]

I have on one occasion experienced the same issue, under otherwise ideal conditions. I never did find a good answer to the problem and hope that I never find myself in a scenario where I need to come to a full stop on hill with a heavy load. I also find that under normal load conditions it does take a bit of speed (about 5-10 mph) before everything locks up as it should and the turbo kicks in. Once that happens I have pulling power all day long. I will continue to look for ways to make the truck behave a little more like a standard tranny with a clutch in those few and far between circumstances. Sometimes you just need or want very high torque applied to the wheels starting at 0 mph.

 

[Tfsick]

Your description sounds exactly like my experience last week with a 14K dump trailer with about 2 ton in it on grass. Had to move forward, full accelerator, nothing. Put it in 4Lo, moved immediately. My 68RFE has a better billet torque converter installed from re-build when it lost 4th,5th and 6th at about 42,000 miles so transmission runs cooler when pulling camper. Not sure what is going on but sounds like I'm not alone.

 

[SouthTexan]

UNDERSTANDING STALL SPEED