3" lift on 2007 DuraMax

[AnolaBob]

I'm contemplating a 3" lift kit for the TV. With tires the TV will be 6" higher. When the 5th wheel is on the truck the back end drops 2". The net height increase should be 4". Based on all the discussions with the pin box hitting the box walls, am I going in the wrong direction. The hitch is a 16K Reese slider. I'm comtemplating a Tri-glide or Mor-ryde as well. We tow a 28" Outback.

Any suggestions would be appreciated. :confused:

[Festus2]

There are two factors to consider after you go about raising the truck :
1) Will the truck and the 5th wheel be level after you drop the 5th wheel onto the truck?
2) Will there be enough clearance between the truck bed rails and the 5th wheel overhang?

When you are hooked up, the two should sit level so that there is equal distribution of weight of both axles of the 5th wheel.

You didn't indicate how much clearance you presently have nor do we know if you are level or not. Is there some particular reason why you are lifting your TV? Does it sit too low after you drop the weight of the 5th wheel onto it?

Would changing the height of your hitch and/or pin box solve any of the problems you seem to have rather than installing a lift kit?

I'm not too clear on what exactly it is that you are trying to accomplish by adding a lift kit.

[sagebel]

A 6" gain sounds high for a 3" lift. What size is the stock block in the rear and what size block will be used to do the lift? What size tires are you coming from/going to? Sorry for all of the questions but I thought the GM trucks need quite a bit of lift to run a larger tire.

[AnolaBob]

The truck sits low when the 5th wheel is attached. The 5th wheel in lower towards the front but not bad. There currently is about 6 " clearance between the truck and the box. The main reason for the lift is to put taller tires on the truck which would not otherwise fit without lifting the truck (no wheel well space up front).
I don't have info on the stock block or new block just yet. My thoughts are 3" lift and additional 3" going to 335X70x17. Currently there is 285x70x17s.

Can the pin box mounting bolts be adjusted to fit this additional height or can a Tri-glide or Mor-ride give more room for adjusting the new truck height?(tx)

[Festus2]

If the hitch - whatever make or model you have - can be raised, that would accomplish part of what you are trying to do ---- make the hitch sit higher in the truck bed and raise the front of the 5th wheel. However, if you cannot adjust the height of the truck hitch, then try moving the pin box down a notch or two. Again, this would accomplish the same thing but wouldn't do anything to raise your truck to allow for bigger tires. Most pin boxes have several holes that allow for adjustments.
If you have about 6" of clearance now and if you lower the pin box, that should increase the clearance and make the front of the 5th sit higher.

[sagebel]

285 70 R17 converts to 32.7". 335 70 R17 converts to 35.5". While the difference is about 3", you will only gain 1.5" in height. Like mentioned in a previous post, if you have some adjustment left in the hitch or pin box you could save the cost of the lift and tires. If you want to take the squat out air bags or timbrens are always an option.

[AnolaBob]

Thanks Festus2 and Sagebel for the good information. Greatly appreciated.
Bob(tx)

[christopherglenn]

Lifted trucks arn't usually the best idea for towing. The larger tires will hurt power, and braking performance. Usually lift springs are softer then stock, so there could be more squat in the rear when you are done. If you are just using blocks out back for the lift, you will need some sort of traction bar (a good idea no matter what the type of lift you do) to control axle wrap.

[AnolaBob]

Sounds like this isn't a good idea. Thanks for the advise everyone.