2006 Pin Box Problems - Montana Owners Club

rickfox · 01-05-2006, 05:07 AM

Good Morning All,

I recently took delivery of a new 2006 3400RL, and for the most part am quite happy. However, I am trying to work through one problem and am looking for assistance.

I have been told by our dealer that starting in 2006 there is a difference between the pin box configuration of all 5vrs less than 34' compared to those that are greater than 34'. I have tried to contact Montana about this but thus far have not gotten a response.

The shorter trailers have a longer more wedged shaped box, while the longer trailers have a shorter more stubby looking box. At almost 38', the 3400RL has the shorter box. My problem is this: when received the box was installed at its highest position in the frame wing mount holes. Since the front of the trailer was riding high about 2.5", I was able to compensate some by lowering the hitch in the truck to its lowest position, but it is still riding high by 1.5". Perhaps I can purchase a different hitch that rides lower in the truck bed, but most other options that might be available start to be very expensive. - By the way, my TV is a standard 2003 2500HD with stock sized wheels, tires, suspension etc, nothing strange.

I believe riding high on the hitch will tranfer some weight off the hitch, but don't have a clue how much or if I should even worry about it.

But the situation is worsened if I were to install a Mor/ryke pin box on the unit (which I want to do) because according to Mor/ryde their design causes the pin to be approximately 1" lower, thus making the trailer front now again ride 2.5" high. Knowing this, Mor/ryde has recommended not installing it on my 2006 Montana 3400RL (We are still investigating the issue hoping to find a resolution).

This sounds scarey to me since I have nothing out of the ordinary in the way of a TV or trailer configuration, and as I have been told by our dealer, in the near future the Mor/ryde pin box will be available on the Montanas. Are we/Montana headed for trouble here?

ken · 01-05-2006, 07:13 AM

I know this is not going to help your situation, but our 2003 3655 Montana came with a shorter pin box. Our 2005 3475 Montana has a longer pinbox. I was told at thatit was an extension pinbox simular to what everyone else had on their Montanas back in the 2004 Rally at Goshen. It was an option back then and mine didn't have one. The 3475 is the same length as the 3400 and with the extension pin box, I have never had to slide the pin back in our new truck when parking.
As far as height, we noticed that the 3475 sat the 2500HD down a little so I added Air Lift air springs. Now were level.

rickfox · 01-06-2006, 02:39 PM

Good Evening,

I finally was able to talk with Montana Customer Support. They confirmed at all 2006 units 34' and under are being built with the extended pin box. All units over 34' are being built with the shorter pin box which does create some turning interferences. Apparantly that is one of the reasons they are coming out with the new 30% improved turning radius front cap. Mostly to get back what was lost in using the shorter pin box. I was told the use of the shorter pin box was required by the manufacturer.

They are investigating my problem that this change has also created a mismatch in the king pin height. Sometimes it's 1 step forward and 2 steps back.

DHenry · 01-06-2006, 03:19 PM

I sure am interested in knowing how this will turn out. Please keep us informed.

sreigle · 01-06-2006, 06:02 PM

Did they say why they went with the non-extended pinbox on the longer units? Was there or is there a problem with using an extended pinbox on those? If not, then you may be able to purchase an aftermarket extension.

Is there any kind of adjustment for height on your pinbox? Probably not or you would have mentioned it. In my opinion, an inch and a half is probably not enough to worry about. I think ours is close to that (see picture below), too. I have room to adjust it out but our pinweight is already at 3300 lbs and I'm not anxious to increase that so have left it as is.

lightningjack11 · 01-07-2006, 05:41 AM

It makes perfect sense to me to go to a shorter box on longer trailers. I have discussed the extended pin box with quite a few dealers and could never get one to agree with me. My feeling is the extended pin box puts additional stress on the frames. For example, it offers "lever" action on the frame to put both down and up stresses on the frames at the pin box weld points. The shorter pin box offers mostly veritical stesses distributing more even pressures on the pin box and frame. Makes sense to me.

Dave e Victoria · 01-07-2006, 08:41 AM

Rick
The amount of weight shift due to a 2.5 inch change in height is very small. If you recall some math, this shift is proportional to a sine function. The angle you are talking about is approximately 57degrees*2.5/(20*12) where twenty is the approximate distance from pin to trailer axle in feet. That works out to about 0.6 degrees for which the sine is 0.01. If your trailer weighs 14,000 pounds, the apparant shift woud be 140 pounds or about the effect of 1/2 tank of water.
Dave

rickfox · 01-07-2006, 02:17 PM

Dave,

I haven't yet worked through your numbers, but it seems reasonable that the weight change would not amount to a whole lot. What concerns me is that I don't think my TV is anything out of the ordinary as far as hitch plate height, and with all adjustments maxed, I am still high. What if I had a 4 wheel drive rear, or a raised suspension, a dually. I'm guessing the problems would only be worse. By using lower profile tires, and making pinbox changes (and possibly other changes unknown to me) it seems to me like Montana may have inadvertently lost their design tolerances that will allow their trailer to roll down the road level.

I know for a fact that the Cardinal I was towing was right in the middle of both trailer and TV hitch adjustment range, so it seems reasonable to me that Montana "should" design it that way also.

Dave e Victoria · 01-07-2006, 03:40 PM

Rick, I agree that something is not right here.(BTW, the bed hieght of a 3500 is identical to a 2500HD acording to the sales brochure). It seems to me the best reason for a level load is it is less inclined to buckle under breaking although I am not sure as I have not worked out the geometry. However, with a fifthwheel you are starting out with a hich point that is about twenty inches above the ideal from a ride standpoint. The ideal would be a hitch point dead center in the rear differential. Raising the hitchpoint would have the effect of increasing the lever arm. Here we are talking about a purely linear relationship. A two inch change could have a ten percent effect on ride. The Mor ryde hitch pin is a simple second order damping system so it should have a 6 db reduction in the forces acting on this same lever. The Mor ryde should show a distinct improvement even considering the change in height. I hope that makes sense.
Dave

Montana_4221 · 01-07-2006, 03:55 PM

Our Rig is an early production 2006 that we bought in 2005 and I think it has the extended pin box. Apparently they made the change after our unit was manufactured. I agree with lightningjack and they may have made the change to address the frame problems that they were having. If that is the case I wouldn't mind changing to the new design.

I have already been considering the Moryde pin box

rickfox · 01-07-2006, 04:23 PM

Thanks for the comments Dave, I hadn't considered the stopping situation. I sure hope my king pin bottom doesn't snap off - ha.

By the way, it has seemed to me and my wife that the 3400 causes the TV rear end to move up and down - a sort of controlled bounce - more than our pervious 5vr which was towing level. Could this be related to the fact that the 3400 is towing high in the front?

We know that the 3400 definitely rolls side to side more than our previous 5vr as you can see the movement in the rear view mirror.

I will be emailing my measurements and a picture of my pinbox to both Montana and Mor/ryde this coming Monday as they requested. Perhaps they will find that my pinbox was a mistake or something like that. I sure would like to add the Mor/ryde pin box but have decided for comply with their rep's recommendation not to do so until the overall situation is better understood.

rickfox · 01-08-2006, 07:11 AM

Dave, another question!

Are you familiar with the Glide Ride? www.glide-ride.com In talking with their customer service, and in reading what another MOC member wrote, their pin box is dimenionally almost identical to the Lippert OEM - no additional 1" of thickness.

Dave e Victoria · 01-08-2006, 01:31 PM

Rick,
I have watched the Glide ride video. I am not sure what the mechanism is inside. The video claims it is not a rubber mount. The only other possibility would be a spring and shockabsorber arrangement. In any event, it has to be "tuned" to the frequencies encountered in the real world just like the rubber mount used in the Mor ryde. Given that the freedom of movement is similar, I would expect very similar performance from both devices. Now, having said that, I would really like to see the actual mechanism inside the glide ride. Being an engineer, i am prone to really appreciate the elegant simplicity of the mor ryde solution. And, I like their up front explaination of how it is made and how it works.
Dave

Montana Sky · 01-08-2006, 06:49 PM

I am curious, for those of us who have an 04 or 05 model with the extended kingpin. Do we need to be worried or consider replacing the extended kingpin for a shorter kingpin to prevent any frame damage or additional stress that will cause problems down the road??

rickfox · 01-09-2006, 08:43 AM

Montana Sky,

From your photo, it appears that your rig is running fairly level. My TV is a 2003 2500HD Crew Cab quite similar to yours.

What kind of hitch do you have, and do you have any extra support (additional springs or airbags) to keep you TV rear level.

When I hitch my 2006 3400RL up, my TV settles about 3" (weighed hitch pin is 2400#). I then use Firestone airbags to bring the TV rear back to level. When the TV is level, the trailer front is 1.5" high. The trailer pinbox is already at its highest adjustment, and the TV hitch is at its lowest adjustment.

Montana Sky · 01-09-2006, 12:58 PM

Rick,
My truck squats approx. 1.5" when hooked and ready to roll. My suspension is stock, no upgrades or changes. I have been thinking about possibly adding the firestone airbags, but the truck rides so well with the coach on it I just cant seem to spend the money.
As for the hitch, I am using the Pullrite Superglide and could not be happier with it. The Superglide is an amazing hitch, but there really is no adjustments on it for height, it is all in the kingpin. My kingpin is set in the middle holes, I have room to make it higher or lower. I also have the factory extended kingpin so I am not sure if that is why mine rides lower or not. I hope you are able to get a solution to your height problem soon.

rickfox · 01-10-2006, 11:01 AM

Good Afternoon All,

After doing a fair amount of research, I have thus far concluded that the Mor/ryde pin box typically places the king pin 1" lower than the comparable OEM pin box ( forces the trailer front up 1" if not otherwise adjusted out), while Glide-Ride is claiming their design actually places the king pin about 3/4" higher (lets the trailer ride 3/4" lower).

Assuming all else is comparable, the Glide-Ride seems to best fit my needs. Interestingly, the Glide-Ride is also available in a model that provides an additional 5 3/4" extension over the OEM. This I like very much.

Any comments about how this extension might change things on the trailer - for example, I'm guessing the rotational forces on the pin box to frame would increase, but I think the actual hitch pin weight would go down.

Will I be better off, worse off, about the same?

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