You guys are full of all kinds of very useful info. I got the Superglide installed today and will be trying to find a P3 and bed plug in the Houston area tomorrow.
If I used the rpm calculator correctly, with a 4.10 amd 35's at 65 rpms should be around 1775. That sounds like a more reasonable towing rpm. I'll play with that calculator some more and try some different combos. I did find a guy who said he would pay to have the lift taken off of my truck and put back to stock if he could have the lift.

I did try the 5er with my old hitch positioned in the bed and the weight of the trailer on it. It did make the trailer sit slightly nose high but not bad. I had roughly 5.75" of clearance above the bed at the tailgate. I'll try it with the superglide tomorrow.
Next on my list will be a programmer and guages while retaining the grab handle on the pillar. I don't know why I have to do things the hard way.

 

With regard to the nose high/clearance above the bedrail issue, I looked at several options, and ended up getting a set of spring perches and welding them on the top of the axles to relocate them below the spring pack.

I figured I could easily put it back if I didn't like it. It turned out to handle fine, and now rides level w/plenty of clearance.

On some 5th wheels, though, doing the axle relocate can give them a bit of a baby buggy look that doesn't look right.

 

I think I got alittle lucky with my 5er in that it sits a little higher than most to begin with.I've still got another hole on the trailer suspesion that I can go up I think. I sure don't want the baby buggy look LOL. I've got everything ready to go tomorrow. the truck is even backed up in front of the 5er for the test run tomorrow. I'm sure I'll probably create more questions than answers on the test run.

 

Cool. I think later 5th wheels were designed with the higher bedrails of late model trucks in mind...

Best of luck with the test run.

I'm kind of kicking around getting a different trailer, myself...

 

On mine I had a lower hole to move the spring to (left pic) but remember if you do that you change the axles camber & toe if you move just the one end and not the center also.
Here are some pics of the center bracket I installed (right pic) to enable use of those additional lower mounting holes on the outer spring mounts.
The center pic was before the change.

 

I didn't think about it changing the camber. Looks like your trailer suspension is similar to mine.
I took the trailer for a test run today. All went well, actually a little better than expected. The trailer actually sat level according to the level on the side. This was with the rear of the truck sagging a little with the weight of the trailer on the hitch but was not down on the overloads yet. I had 6.25" of clearance at the tailgate. So the way the trailer currently sits when hooked up is ok. Now for the pull.
As someone mentioned, I won't be winning any races from a stop sign when loaded but it was not too bad. My father in law who was riding with me actually commented that it seemed to pick up speed better than his truck with 4.10's ( not a Cummins). We had a very strong South wind coming off the Gulf and going North the truck did very well. Get it up to speed, shift into OD and listen to Cummins music. The trip back south was different. Here's where you could tell that I could use some more gear (or smaller tires) but the headwind give me more of the true test that I wanted. Pulling below 65, I didn't feel real comfortable with. Don't get me wrong, the cummins would do it, but I felt like I was lugging it and the tranny would appreciate me shifting out of OD which I did. Now the truck would do anything that I wanted, the only problem being that it was running at~2400 rpms at 65-67 but it was still smooth and fairly quiet on the inside. This was the first time that I have ever pulled that kind of load with a cummins and I have to say that I was impressed. I think I'll make a few short pulls locally before doing anything else. Might also give me a chance to see what 33" tires look like on the truck if I can find someone to let me try them.
Sorry for the longpost guys but I did want to post up what my results were and tell everyone Thank You for the advice,info etc. that ya'll have given.

 

Sounds like that worked better than I figured. Running the engine all day long at 2400 RPM won't hurt a thing.

A temp probe in the hot line from the transmission would be a wothwhile investment, if you don't have one.

 

Gauges will be my next project. Then maybe a Smarty.

 

I've got 35's and a 4.5" lift and 3.73's and I always use the tow/haul when towing. And I sometimes just use OD when hitting a hill - like mentioned above, you won't win any races, but you will get the job done. There are a lot of 7% hills around here, and I like to keep the rpms up around 2-2500 and don't worry much about the speed - there's always someone who wants to pass you no matter how fast you are going, and I can keep up just fine with the normal traffic.

 

One thing about automatics and towing that a lot of people don't understand is that when you tow in O/D the internals of the transmission slow down. So, you have a big load that generates a lot of heat, an engine that makes huge torque and then the pump in the transmission is not circulating the fliud which equals easy overheat condition. Compound that with larger tires and the life of your transmission is greatly reduced.
Same applies to manual transmissions that are splash lubed, big load and no rpm's add up to one hot trans. As well, have you ever seen the actual size of the final gear in an NV5600 or NV4500 ?

That is why most owner's manuals tell you not to tow in O/D, not because the truck doesn't have the power to pull in that gear, it is because the transmissions will overheat from not being lubed properly.

 

I would think that a 4.10 swap would be about perfect, if you want to keep the truck the way it is. If it tows well like that, no reason to change back. 4.10's will probably drop your mileage very little, but it will let the rest of driveline live so much easier. 4.10's will get you about back to stock towing numbers as when you had stock size tires. Then add the Smarty and gauges and you will be in good shape. Towing with the 4.10's will allow you to stay in OD (less overall RPM's) and probably net you better mileage towing. I know my truck will pull almost any hill around with my toyhauler hooked on the rear at 2200 RPM's. Anything over that is just added cooling effect. Scotty

 

That's what I'm thinking also. I think that I'm going to start looking at trying to locate the hard parts. I've got a short to pull to make just after Christmas, mostly on flat back roads where I can play with the speed and RPM's. The local economy is starting to take a hit and the brother in laws shop could probably use the work after the first of the year if I decide to just hire it done.

Anybody know where to start looking for the 4.10 parts?