New tow vehicle and need some help with factory air suspension and hitch issue

[RClifton]

Hi All,

I recently upgraded my tow vehicle to a 2017 Ram 3500 Limited with the 6.7l Cummins (Non HO version), with the factory rear air suspension and I am having some issues setting it up to tow my travel trailer.

I've been using a Curt weight distribution hitch with my trailer for several years now. I'm not sure what the model number is but it has the spring bars with the chains etc and has worked well during that time. The issue that I am having is that when I connect the trailer to the truck the rear air suspension pretty much levels the truck out to where it was before the trailer was hitched.. As an example the Front fender is 40" from the pavement when unhitched and the rear fender is 41.5" unhitched. After hitching up the front fender ends up at 40.5" and the rear fender is 41". This is without the bars attached.

If I attempt to connect the bars after the trailer is connected as soon as their is tension on the bars the rear air suspension starts flipping out loading and unloading air for a few minutes before settling down somewhere between no tension on the bars and way to much.. In 5 attempts to set it up varying the link I used to set the initial tension, twice it stopped adjusting itself with no tension on the bars. The other 3 times the tension on the bars was to much, including once to the point that I was worried about something breaking..

Does anyone happen to have a similar truck with factory rear air suspension that's got it working and could give me some tips? Should I just ditch the bars since the truck is level? I went and got my initial weight without the trailer today and plan to re-weigh it tomorrow without the spring bars to see how much weight was removed from the front with the trailer hitched as well..

[Dennis852]

I had a similar issue with my 2018 Ram 2500. I replaced the rear coil springs with a full kelderman air ride kit with an onboard compressor that auto levels to whatever psi I have the bags set to. This is an issue when hitching and un hitching my 5th wheel. When I would set the jacks down to raise off the plate it would start lifting the truck back up to fill the bags and make it almost impossible to un hitch by myself.

The only way I was able to get this to stop was to leave the truck off while hitching. I plan to wire in a toggle switch when it starts bothering me more but for now I can deal with it.

[ttavasc]

I would suggest temporarily disabling the suspension via the Uconnect settings. I believe there is a "Tire Jack Mode" that you can select which does this so that you don't have to worry about the suspension activating while changing a flat. Once you disable the suspension then I would proceed with adjusting the hitch as normal including the bars and chains. Use before/after fender measurements while the suspension is off to confirm your adjustment.

Once you have it dialed in then disable the "Tire Jack Mode" to activate the suspension. There shouldn't be too much for it to do at that point. I had the 4-corner air suspension on my 1500 and while they do operate a bit differently this was the only way I could get the hitch dialed in properly. I would recommend using "Tire Jack Mode" when unhitching as well.

Also, given that the suspension always wants to return to level you may find that you need to move the ball height down to level coupler height or maybe even an inch below level to avoid having the suspension lift the tongue slightly above level when it compensates after the bars and chains are in place.

[bneukam]

With your new truck do you even need weight distribution? Reese and maybe some other hitches can provide sway control only. Just a thought.

The HD trucks air suspension is a totally different system than the 1500 4 corner air.

[ttavasc]

Originally Posted by bneukam

With your new truck do you even need weight distribution? Reese and maybe some other hitches can provide sway control only. Just a thought.

The HD trucks air suspension is a totally different system than the 1500 4 corner air.

True - which is why I stated that the 4-corner operates a bit different although the general behavior is the same - always return to a specific ride height when conditions warrant such as added weight. The process I described was one I found on a RAM HD forum after I was having similar issues to what the OP is describing. This appeared to be working well for those with the HD's so I gave it a try on my 1500 and it significantly improved the hitch/unhitch process along with allowing for better hitch adjustment.

I suppose it could be possible that weight distribution isn't needed but since no trailer or tongue weights are known at this time, nor do we know what the previous tow vehicle was it's hard to say. But certainly worth looking in to.

[tuffr2]

You are not the only one with this problem as this is about the 12th time is saw this issue. That the auto leveling feature undoes the WD hitch tension.

Good luck figuring it out and please post what you end up doing.

[bneukam]

Originally Posted by ttavasc

True - which is why I stated that the 4-corner operates a bit different although the general behavior is the same - always return to a specific ride height when conditions warrant such as added weight. The process I described was one I found on a RAM HD forum after I was having similar issues to what the OP is describing. This appeared to be working well for those with the HD's so I gave it a try on my 1500 and it significantly improved the hitch/unhitch process along with allowing for better hitch adjustment.

I suppose it could be possible that weight distribution isn't needed but since no trailer or tongue weights are known at this time, nor do we know what the previous tow vehicle was it's hard to say. But certainly worth looking in to.

The 1500 is different than the 2500, which is also different from the 3500. The 3500 is only an air assist. The 3500 have a normal, and alternate ride height. Different procedures than just putting it in jack mode. I don’t know enough about it, but have read where you have to use alternate setting for WDH bars.

Was going off the trailer listed in his sig.

Just removed the air junk off my 1500, and was surprised on how cheap it was.

[move on]

Originally Posted by RClifton

Hi All,

I recently upgraded my tow vehicle to a 2017 Ram 3500 Limited with the 6.7l Cummins (Non HO version), with the factory rear air suspension and I am having some issues setting it up to tow my travel trailer.

I've been using a Curt weight distribution hitch with my trailer for several years now. I'm not sure what the model number is but it has the spring bars with the chains etc and has worked well during that time. The issue that I am having is that when I connect the trailer to the truck the rear air suspension pretty much levels the truck out to where it was before the trailer was hitched.. As an example the Front fender is 40" from the pavement when unhitched and the rear fender is 41.5" unhitched. After hitching up the front fender ends up at 40.5" and the rear fender is 41". This is without the bars attached.

If I attempt to connect the bars after the trailer is connected as soon as their is tension on the bars the rear air suspension starts flipping out loading and unloading air for a few minutes before settling down somewhere between no tension on the bars and way to much.. In 5 attempts to set it up varying the link I used to set the initial tension, twice it stopped adjusting itself with no tension on the bars. The other 3 times the tension on the bars was to much, including once to the point that I was worried about something breaking..

Does anyone happen to have a similar truck with factory rear air suspension that's got it working and could give me some tips? Should I just ditch the bars since the truck is level? I went and got my initial weight without the trailer today and plan to re-weigh it tomorrow without the spring bars to see how much weight was removed from the front with the trailer hitched as well..

You didn't say what trailer you have or how much tongue weight you're carrying but if it only raises the front end up by 1/2" I would think that you don't really need a weight distribution hitch. I would try it without the WD hitch. Get it weighed and if you're not overloading the rear axle you're good to go.

[ttavasc]

Originally Posted by bneukam

The 1500 is different than the 2500, which is also different from the 3500. The 3500 is only an air assist. The 3500 have a normal, and alternate ride height. Different procedures than just putting it in jack mode. I don’t know enough about it, but have read where you have to use alternate setting for WDH bars.

Was going off the trailer listed in his sig.

Just removed the air junk off my 1500, and was surprised on how cheap it was.

I'm not seeing a sig line in the OP - are you looking elsewhere?

I wouldn't disagree on the junk status of the 4-corner components. While I never had any issues with it the 5 years/55K miles I had it, I did worry that it was going to leave me stranded at a most inopportune time. Extremely cold climates it was pretty much a given that you were going to have issues. It sure did provide a nice ride though - both empty and towing once I got the hitch dialed in. Had I gone with a RAM HD instead of the F-250 this was one option I would've skipped though.

[ttavasc]

I found the following details on the Cummins Forum from back in late 2017 (since the OP has a 2017 3500) - appears to have direct input from RAM engineering as it pertains to the differences between the 1500/2500/3500 air systems as well as their recommended procedure for hitching/unhitching, including conventional trailers. They will call out items that apply to just a specific model as needed. Hopefully this will help the OP:

"Straight to the point. The folks at Ram Truck Engineering read your comments in our Issue 89 article about the Ram factory air suspension packages (pages 18 – 21). As they further refine these three distinct air suspension options (yes, the 1500/2500/3500 trucks all work a little differently), they would like your further comments and suggestions.

Here is the format we will use. The Ram folks and I have made separate areas for each truck – 1500/2500/3500. There is an introduction/principle-of-operation area (for folks like me who didn’t bother to read their Owner’s Manual). This is followed by a description of the time delays that are programmed into each system. Next (again for those like me that did not read the Owner’s Manual), they give you the proper way to hook up a trailer. Follow this data which is in your Owner’s Manual (yep, I learned something new), and you will better understand the design parameters of the air system. Finally, “The Request for Input.” Here is your chance to tell the Ram staff the good/better/best or good/bad/ugly from your perspective.

Thank you for your participation.

Ram 3500 Supplemental Air Suspension

The 3500 differs from the 2500 system in that it has rear leaf springs to support the truck's higher GVWR ratings. The addition of these springs can prevent some vehicle configurations from being able to obtain the lower “alternate trailer height” when unloaded as the leaf springs alone hold the vehicle at the normal ride height when unloaded. Therefore, these vehicles must be loaded before alternate trailer height can be obtained.

Auto Leveling – Time Delay
Like the 1500 system there is an added delay to give a “steel suspension like” behavior. However, with the additional load capacity of the 3500 system, a two stage strategy was developed. When lighter loads are applied the delay time is 10 seconds. Heavier loads will trigger a 20 second delay. Just like the 1500 truck, the engine should be left running when loading the vehicle if auto leveling is desired.

Key Off Strategy
Like the 1500 truck, the 3500 system will also make adjustments to maintain a target ride height after the ignition has been turned off. The air suspension system will stay active for 10 minutes after key off. However, the 3500 system will only lower during this time frame and the compressor is not allowed to run.

Door Open Strategy
Since the 3500 system is a rear axle only system, lowering of the suspension may occur while any door is open.

Trailer Hookup/Unhooking
The alternate trailer height may be used as a way to raise and lower the truck to minimize trailer jacking. The vehicle will always adjust to meet target ride height when using this feature as long as the air suspension system is not being overloaded. However, the following guidelines should be adhered to when hooking up and unhooking a trailer:

When using load distribution bars for conventional towing, select the height you plan to tow at (Ram recommends alternate trailer height) and then adjust load bars as needed (see "Hooking up a Trailer With a Weight Distributing Hitch").
When hooking up or unhooking a fifth wheel trailer, place the vehicle into Tire Jack Mode to prevent automatic height adjustments easing the ability to slide the kingpin out of the head without binding.
Never hook/unhook a trailer or place a load in the bed of the vehicle while it is in transport mode. Transport mode deflates the air bags to lowest safe level possible when selected and the air bags may be damaged by applying additional loads to the vehicle.

Hooking up a Trailer with a Weight Distributing Hitch (all trucks)

Set air suspension to normal ride height. No action is required if already in normal ride height. NOTE: The vehicle must remain in the engine running position while attaching a trailer for proper leveling of the air suspension system. NOTE: For Ram 2500/3500 trucks equipped with rear air suspension, normal ride height or alternate ride height can be used.
Position the truck to be ready to connect to the trailer (do not connect the trailer).
Under radio suspension settings, turn on jack mode. Jack mode will be canceled and procedure must be restarted if the vehicle is driven at speeds above 5mph (8kph).
Measure the height of the top of the front wheel opening on the fender to ground, this is height H1.
Attach the trailer to the vehicle without the weight distribution bars connected.
Measure the height of the top of the front wheel opening on the fender to ground, this is height H2.
Install and adjust the tension in the weight distributing bars so that the height of the front fender is approximately H2-H1)/3+H1 (about 1/3 the difference between H2 and H1 above normal ride height [H1]).
The truck can now be driven. Jack mode will be canceled when driven at speeds above 5mph (8kph).

Request for 3500 Input
Ram truck engineering wants your input on the delays implemented during the auto leveling strategy to provide the “steel suspension like” behavior. When replying please include the following information:
Length of time owning a Ram truck with the factory air suspension system
Typical usage in which you interact with the air suspension (type of trailer being hooked up/unhooked, type of loads going the bed, etc.)
Suggested delay time
Description of why does the delay time need to change or why should it stay the same

Note: This delay is in addition to the amount of time it takes the system to assess the change in height, actual response times to applied loads will vary."

[bneukam]

Originally Posted by ttavasc

I'm not seeing a sig line in the OP - are you looking elsewhere?



I wouldn't disagree on the junk status of the 4-corner components. While I never had any issues with it the 5 years/55K miles I had it, I did worry that it was going to leave me stranded at a most inopportune time. Extremely cold climates it was pretty much a given that you were going to have issues. It sure did provide a nice ride though - both empty and towing once I got the hitch dialed in. Had I gone with a RAM HD instead of the F-250 this was one option I would've skipped though.

My bad, I clicked on his user name. It list a 30’ Fleetwood Prowler.

My problems started at -10 degrees, and never worked right again. Truck would always be at different ride heights. It leaned from side to side about 1 1/4 “. The front, and back would also sag depending on the day. Ram engineers couldn’t fiqure it out even after replacing a 800 dollar control module. Put on a Fox 2.0 system with rear Tufftruck coils. Rides, and tows much better now.

If anybody needs a front air strut, or rear bag, send me a pm.

[6_Riders]

States require equalizers above a certain trailer weight. Do not tow a 30' trailer with out the equalizer.
Read the owners manual, that's why vehicles come with them.

[Jshopes81]

Originally Posted by 6_Riders

States require equalizers above a certain trailer weight. Do not tow a 30' trailer with out the equalizer.
Read the owners manual, that's why vehicles come with them.

I just spent 20 minutes searching and couldnt find anything to back up this claim, so, care to cite your source for this? Ive got a class v hitch on my ram work truck and ive never towed with anything more than a triball. The reciever is rated for 12k and 1200lbs. Ive pulled a big enclosed car hauler type trailer and my jayco 324bhds with no form of weight distribution or sway control with absolutely 0 issues. My work truck is a 17 ram 3500 srw, i would think that the op truck is set up at least the same from the factory.

[jacknife]

I have. 2020 factory air . It is pretty simple hook up then hit alt ride ht truck levels that is with a fifth wheel . I really don’t see a need for equalizers on a TT with a 3500 towing it . just anti sway should do it . I have had air bags on big rigs for 35 years in every imaginable weather condition and they are a proven system . Rams system seems very simple to operate . I am quite satisfied with it and the ride it produces. Go down the hiway and you will be hard pressed to find a rig without full air bag suspension . Because it works and provides a smoother ride then springs .