Tow/Haul mode and when are trailer brakes engaged?

[COCamping]

So we took our 2016 Rezerve on it's first trip this past weekend. We stayed more on the plains of Colorado and didn't head up into the mountains, though with any drive there are some hills. our 2014 Ram 2500 handled it all really well. However, there were a couple of instances that we felt like something wasn't working properly when slowing down and we're trying to narrow it down. My gut tells me there's something wrong with the trailer brakes, husband isn't sure.

So we had the truck in tow/haul mode with the exhaust brake activated. On a couple of instances when starting to descend a hill after a climb the truck downshifted aggressively, but we also heard a big clunk from the hitch. As a passenger I felt like it was the trailer pulling back on the truck. The rest of the time on the road I didn't feel much as a passenger and my husband felt the trailer brakes were reacting as expected with the truck brakes.

I've also noticed when at our storage lot (all gravel), when my husband comes to a stop from about 5-10 MPH max, it appears that at least one of the trailer tires is skidding. I'm frequently outside of the trailer to direct into our spot, so I get a closer look of what's going on. I'm kind of wondering if there is a problem with the brakes that's possibly locking up one or more wheels. My husband does do a manual check of the brake setting every time he hooks up, making sure they engage. I was not in the truck when he tested the last hookup, so I can't say how strong of a pull the trailer had when manually engaging the trailer brakes.

The truck is new to us as well and there's no info in the owner's manual on how the tow/haul, exhaust brake works in combination with the trailer brakes. With that info...

Anyone know if the brake signal is sent to the trailer when the truck downshifts?
Any ideas on things to look at and check before we call the dealer for assistance?
We are also open to hearing what you folks use to test your brake controller settings.

Thank you.

[Lloyd]

When you were going down hill and the truck shifted aggressively as you stated, the clunk you heard was probably the king pin moving back or ahead inside of the jaws on the hitch with the sudden change in speed/down shifting.

I always do a test pull immediately after hooking up and the jaws locked and before raising the front legs. This is done with using the brake control lever in the manual mode. I want to make sure the jaws are locked before pulling ahead. You don't want to drop the rig on your truck.

You can test your trailer brakes in the gravel by going about 5 mph and using the manual mode to set them. You should then be able to see if they are set equally and locking up at the same time.
If they aren't, then I would recommend getting them adjusted. If you think this something you are comfortable doing yourself, it's not that difficult. If not then I guess you would have to rely on a dealer or some other service center.

[COCamping]

Thanks, we are pretty sure that the clunk is the king pin, the part I'm worried about is feeling like the trailer was pulling back on the truck. Maybe it was because I was the passenger and not the driver, so the sensation is different. So trying to determine if the truck would have even sent a brake signal to the trailer on a downshift (did not press the truck brakes).

We do a test pull to make sure all is hooked up. Just as you described, manually engage the brakes before raising the legs and pull ahead. Read other people's horror stories about dropping the trailer on the truck and are trying to avoid repeating those mistakes.

When it comes to adjusting the brake controller how hard should the trailer be pulling back when manually engaged if set properly? With our popup we were told just to the point that the tires locked up, so we started low and increased slowly until that occurred. Does the same apply to the larger rigs?

We are definitely comfortable driving around the lot and watching to see how the tires react when braking (manually engaged or otherwise), adjusting the brakes is a whole different story, but at least if we can call the shop knowing what is going on that should help us.

[Lloyd]

I don't know for sure how your Dodge works in respect to sending a signal to the trailer brakes with out you activating them. In my opinion, that doesn't happen.
Hopefully one of the Dodge guys will chime in here and clarify.

[Ken]

I can tell you that my brakes do not engage when the engine brake is activated in tow/haul mode. You can adjust the setting of your factory trailer brakes but I can't remember at the moment how but it took me awhile to get it dialed in to my trailer. The good news once it is dialed in you can barely feel the trailer when braking. I do remember some post about wheels locking up when braking do to brake wires that were loose on the axles or something like that. But I would bet you just need to dial in your truck setting look in your manual that's were I found out how to adjust mine, if I remember correctly my setting is ( heavy trailer set on 8 )

[COCamping]

Originally Posted by Ken

I can tell you that my brakes do not engage when the engine brake is activated in tow/haul mode. You can adjust the setting of your factory trailer brakes but I can't remember at the moment how but it took me awhile to get it dialed in to my trailer. The good news once it is dialed in you can barely feel the trailer when braking. I do remember some post about wheels locking up when braking do to brake wires that were loose on the axles or something like that. But I would bet you just need to dial in your truck setting look in your manual that's were I found out how to adjust mine, if I remember correctly my setting is ( heavy trailer set on 8 )

Thank you. We do know how to adjust the brake setting. I think we were set to heavy trailer 6 on our last trip. I didn't think the brakes would engage when downshifting, but wasn't sure. My husband is going to take it out one day and change his truck display to show what is happening with the trailer brakes and see if it does it again. Quite possibly just a big bump from the aggressive downshift that we're not used to. We'll also take it out in the storage lot and have me do a visual for the wheels locking up.

Want to work out these little unknowns before we go on a long haul. We are still working on another weekend trip or 2 within a couple hours of home before we winterize to get more comfortable.

Thanks for the input.

[r2millers]

Originally Posted by Ken

I can tell you that my brakes do not engage when the engine brake is activated in tow/haul mode. )

To Lloyd's point, your 7 pin connector has only 1 pin used for braking. It sends a signal based on voltage to the brakes for actuation.

This signal is sent from your controller and the engine brake doesn't affect that control.

Your tow/haul feature changes the shift points both up and down, helping to keep you in the correct gear and also keeping your tranny cooler as a result.

The trailer doesn't know if the engine brake is working or not, just receiving the signal from how much brake is applied.

Can you imagine if you had to make an emergency stop when the engine brake was activated and the trailer was diabled? Not a pretty picture!

It can feel like the trailer brakes aren't as effective when the engine brake operates because of the "push" effect going down a grade.

[COCamping]

Originally Posted by r2millers

It can feel like the trailer brakes aren't as effective when the engine brake operates because of the "push" effect going down a grade.

The problem is I felt like the trailer pulled back on the truck when it downshifted. Maybe it's just the way the truck downshifts that I'm not used to. We've only had the truck a couple of months and got it specifically to buy this trailer. Our previous setup was a 2006 minivan and a popup (with electric brakes, but a totally different feel when towing).

Thanks for the detailed description about the brake controller.

[r2millers]

I just think it's getting used to a bigger load behind you. Keeping playing with your controller to get the right setting. I set mine on 7 after playing with it for a bit. If the roads are wet, I drop it down to 6 to avoid lock up and slow down with more distance ahead of me.
The clunking is pretty common and not much to be concerned about if everything is secure. Just make sure you aren't using a 2" ball on a 2 5/16" receiver!

[COCamping]

Originally Posted by r2millers

I just think it's getting used to a bigger load behind you. Keeping playing with your controller to get the right setting. I set mine on 7 after playing with it for a bit. If the roads are wet, I drop it down to 6 to avoid lock up and slow down with more distance ahead of me.
The clunking is pretty common and not much to be concerned about if everything is secure. Just make sure you aren't using a 2" ball on a 2 5/16" receiver!

Ball size is not an issue with the 5th wheel, but I'm guessing there's a story behind that advice. I've learned a lot from reading up on other's mistakes.

[r2millers]

Originally Posted by COCamping

Ball size is not an issue with the 5th wheel, but I'm guessing there's a story behind that advice. I've learned a lot from reading up on other's mistakes.

My mistake. I was still thinking about your smaller trailer and didn't realize you upgraded to a 5th wheel.
Yep. Many stories about trailers coming off the ball because of using too small of balls.
Usually a 1 7/8" ball on a 2" receiver.

[Dayle1]

On gravel, even slight differences in trailer brakes, especially on a new unit can result in one tire locking up while others don't. Differences in the amount of weight on each tire, actual tire pressure, position of each star adjuster, voltage drop to each magnet and wear pattern of the shoes against the wheel drum are some of the variables. If this also happens on dry pavement, then further investigation is needed. Or just do multiple stops on gravel, some straight, some turning left, some turning right. If the same wheel always locks up, again there may be a bigger problem. Something else to try is check the temp of each drum after stopping with minimal use of the foot brake, coasting to a stop would be ideal, if not use the transmission manual mode for most of the braking. If one drum is significantly hotter than the others, then it is suspect, an IR temperature gun is ideal for this check.

I agree with other comments, during a transmission downshift, if anything the fifth wheel will push against the truck not pull back. However, if there is a significant dead zone during the gear change, you may feel like the trailer is holding the truck back because the truck is kind of like coasting in neutral during the gear change.

Finally, even with fifth wheels, in an ideal world the trailer should brake slightly more aggressively than the truck and feel like it is dragging. You never want the trailer to push the truck while stopping because it can also push the truck in the wrong direction. Especially under wet or icy conditions.

[COCamping]

Originally Posted by Dayle1

On gravel, even slight differences in trailer brakes, especially on a new unit can result in one tire locking up while others don't. Differences in the amount of weight on each tire, actual tire pressure, position of each star adjuster, voltage drop to each magnet and wear pattern of the shoes against the wheel drum are some of the variables. If this also happens on dry pavement, then further investigation is needed. Or just do multiple stops on gravel, some straight, some turning left, some turning right. If the same wheel always locks up, again there may be a bigger problem. Something else to try is check the temp of each drum after stopping with minimal use of the foot brake, coasting to a stop would be ideal, if not use the transmission manual mode for most of the braking. If one drum is significantly hotter than the others, then it is suspect, an IR temperature gun is ideal for this check.

I agree with other comments, during a transmission downshift, if anything the fifth wheel will push against the truck not pull back. However, if there is a significant dead zone during the gear change, you may feel like the trailer is holding the truck back because the truck is kind of like coasting in neutral during the gear change.

Finally, even with fifth wheels, in an ideal world the trailer should brake slightly more aggressively than the truck and feel like it is dragging. You never want the trailer to push the truck while stopping because it can also push the truck in the wrong direction. Especially under wet or icy conditions.

Thank you for the detailed explanations and possibilities. This will definitely help us out as we get used to towing the new rig.

It's sounding like it just might be a different feeling for me as the passenger than I'm used to. But we'll still investigate a bit on our own to make sure.

[frosty42]

Being a fellow Ram owner, I would recommend on the next trip to the dealer, have them check the voltage output on the plug receptacle to make sure there are no issues. A few fellow Ram owners on the Cummins forum have reported voltage issues on the integrated brake controller.

Otherwise, it's a matter of getting comfortable with the setup and using the settings on the controller. FYI...I have mine set on "light towing" as that was what came up when I first plugged in. I think I have the controller at around +6 or so.