Towing a Jeep (and some other stuff) - Q's

I've actually got two separate towing/hauling questions.

1 - This weekend I am going to be throwing some aluminum (some kinda heavy) and wood furniture into the back of the pickup (not on a trailer). Should I use the tow/haul button? It's about a 40 mile trip through semi-hilly terrain, ranging from highway speed to school zones.

2 - I got this truck specifically so I could haul my Jeep to far away off-road parks. Is there anything I should be aware of, worry about, take precautions for? I have a Reiser 2 axle 10,000 GVW trailer that weighs 2,220lbs (steel and wood) and it has brakes, a brake-away system, etc. My Jeep (likely) weighs 6300-ish pounds, bringing the total haul weight to 8500-ish pounds. I got some advice on tie-down procedures from AW Direct who seemed knowledgeable re: my 37" tires and lift kit on the Jeep. My truck is rated at 9900lbs tow capacity. For mostly highway driving (rural CT to rural Pennsylvania), what would you use for gain on the integrated brake controller?

I'm a towing newb so just trying to calm my nerves/fears.

Truck specs:

2014 1500 5.7L v8 Hemi Laramie Crew cab 6'4" bed, no air suspension, 3.92 LSD, tow group mirrors, integrated brake controller, 8 speed automatic.

In response to your first question. I would not worry about the tow haul button for the stuff in the back of your truck. It doesn't sound heavy enough to me to really worry about. That being said, if you see your truck shifting a lot, and your tranny temps going up the load might be making a difference, and you should think about kicking it in.

Second question, get everything loaded up, safely secured, and in a safe place, preferably very nearby your loading point apply the trailer brakes at a low speed and see what happens. Increase the gain until this maneuver causes them to lock. Then drop them down a click, or two. You do not want your trailer brakes locking on you while driving, but at the same time you don't want the trailer to push your truck all over the road because the trailer brakes aren't doing their fair share of the work.

Keep in mind that combination probably weighs more than your truck does, so leave plenty of following distance, and when you first start out keep your eyes open for sway, and if you feel the tail moving around much while speeding up, believe me it gets much worse when you stop accelerating, and are traveling at full steam. Downshift, and use your trailer brakes as possible to slow you down, so you don't burn up your truck brakes. Also, don't floor your brakes in a corner... ABS won't save you in normal driving conditions, and it definitely won't save you when you have 8,000+lbs pushing the ass of your truck sideways.

Drive smart, and watch out for morons, that is the most important piece of advice! You will do fine!

Thanks for the advice... this is definitely good stuff. I can throw my Jeep at a 60 degree rock-covered hill and not feel worried at all, but for some reason the idea of towing my Jeep down a paved road scares the crap out of me. Mostly I figure it's the fear of the unknown ... I've never done it before.

jlb said:

In response to your first question. I would not worry about the tow haul button for the stuff in the back of your truck. It doesn't sound heavy enough to me to really worry about. That being said, if you see your truck shifting a lot, and your tranny temps going up the load might be making a difference, and you should think about kicking it in.

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Stupid question - other than watching the tachometer blip, how do I know the truck is shifting? My wife's Grand Cherokee, which has a nearly identical in-dash cluster, shows the current gear right next to the "D", but mine doesn't. Is there a particular EVIC screen that shows the gear? Occasionally I can feel a shift but, especially like in the 2-4 range, it's so damn smooth I can't tell it's shifting unless I really pay attention.

And one more thing.. I've seen some threads on this forum talking about changing tires for towing optimization, load ranges, P vs LT tires, and other things that all seem like reading a foreign language.

My question is - if my truck is rated at 9900 pounds off the lot, does it come with tires that are suitable for that task? Do I need to replace my brand spanky new stock tires with higher load range tires? I only intend to do the heavy weight towing like 4-5 times per year, max.

No such thing as a stupid question, only stupid answers.

The only answer to the shifting is to keep an eye on the blipping as far as I know, but I only have a 2011 with the older EVIC. You can also shoot the EVIC over to the tranny temp screen, and keep an eye on that. I think mine tends to ballpark 130-140, but I think they say "hot" is considered like 180(?), then again I also have the 5-45RFE not the ZF 8spd. I highly doubt you will need tow haul mode though.

For the tire stuff... Long story short your truck is rated, and has tires capable of allowing it to tow the 9,900 lb trailer. Whether or not that is ideal is a different matter. One thing people complain a lot about with the half tons is trailer sway, and the rear end wanting to walk around. The typical cure is to buy an expensive weight distributing/anti-sway hitch setup. This however is only treating the symptoms, and not addressing the underlying problem of WHY it is swaying.

Any more half tons are not really trucks, they are big cars due to the typical consumer who buys them. As a result they need a compliant ride, reasonable handling, and a focus on features normally associated with passenger vehicles. In order to achieve the compliant ride the 20" rim trucks come with P rated tires, and the 17" rim trucks come with LT C rated tires. I am not sure what the actual difference is here, they have very similar load capacities, and I think the same number of belts(?). These tires have very flexible sidewalls which results in a more compliant ride than vehicles with D (minimum), or E rated tires, like most tow vehicles would be equipped with. These compliant sidewalls allow the truck to walk sideways all over the place. As a test go stand near the back corner of your truck, grab the top of the bed rail in the corner, and shake the truck back, and forth. You will find if you do this at the right frequency you can get the truck to move up to around 4". This is called the harmonic frequency. The frequency is determined by spring rate (the sidewalls of your tires), damping (there isn't much in this scenario ignoring all the internal friction in the tire sidewalls), and mass. Increasing the mass, and keeping the other two things constant (hooking up a long trailer) will lower this harmonic frequency, making it easier to obtain, and this is why you develop a slow sway that grows until you wipe out off the road. The harmonic frequency will result in vibration that grows until something fails, your vibration is sway, and the failure you eventually experience is traction loss as your trailer goes 90 degrees to the road.

All the discussion of changing tires stems from the simple fact that they have a higher spring constant, and higher damping since they have much stiffer sidewalls. That means your harmonic frequency stays higher, and is more difficult to achieve in normal circumstances. I am of course assuming you intelligently load, and balance your trailer, and am ignoring all freak circumstances. If you do the same shaking test I mentioned before on an identical truck, but with E rated tires you will find it may only move back and forth a couple inches, and at a much higher frequency.

That was probably way more information than necessary, but it can be informative, and interesting to learn for the right person. The big point is, higher rated tires reduce sway, and make towing easier, and safer, but they decrease ride compliance, resulting in a harsher ride.

Tow with confidence, the 1500 is a great tower for its size.

I'd suggest getting some airlift 1000 air bags to help reduce the squat, and make sure you distribute at least 10% of your weight to the truck. Before going on your first trip, take the loaded trailer out for a drive. Move the jeep forward 6" on the trailer, then try again to see what feels more stable.

The rest of the advice given is solid. Definitely use the tow/haul mode when towing heavy, and set the gear to "7" if it's hilly. 8th speed will be useless on anything but nice flat ground, or downhill.

The main thing you need to keep in mind is that your load out weighs you by quite a bit and it can get away from you quick. Don't be scared to do it your truck is rated for it you just have to use your head and drive like you have 9000lbs behind you. Take your time and load your jeep and take short drives re adjust forward and back until you find the optimal location for your jeep on the trailer. You need to adjust your trailer brake because the trailer will do most of the work. On the trailer brake it has a slider that will allow you to use the brakes on the trailer separate from the truck. That will allow you keep tabs on the trailer if it starts swaying. With that much weight I would suggest the air lift 1000 assist springs, weight distribution hitch and sway control. Try to get speed before you go up hills to avoid a lot of down shifting. Constant shifting is what heats up transmissions. You may do a little bit of research but I think the 8 speed runs hotter than the 5&6 speeds your gauge will tell all. Happy towing.

14hemiexpress said:

You may do a little bit of research but I think the 8 speed runs hotter than the 5&6 speeds your gauge will tell all. Happy towing.

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It sure does. 185-190F is normal unloaded. I wouldn't get too worried about trans temps until they get over 210F. I can't remember what the manual says but I think the real danger zone is much higher than 210F