Who pulls a heavy load with a lifted truck?

[MACH26]

I have a Duramax that I'm thinking of putting on 37" tires, Edge Juice, exhaust, and intake. I pull a 34' Weekend Warrior (11K lbs), will I need to worry about the drivetrain or regearing or ???
Thanx Javier

[Jordy]

A 34'? Unless that's a bumper pull, you're really going to have to rework the trailer to get under it if it's a 5th wheel. Talking about axle flip deal, and then the geometry for the rear ramp (not to mention just getting in and out of the door) become a little more of a challenge.
Even if it's a bumper pull, you end up having to run a huge drop hitch. Just something to think about.
Regearing would be something to consider as you'll likely lose alot of the lower end when you essentially change over to some highway gears with the 37's. I'm running 285's on mine and my speedo is off by around 5 mph at 65. Expect quite a bit bigger jump with the bigger tires.

[MACH26]

Yes it is a bumper pull, and I'm going to have the speedo recalibrated and I've already added airbags to the rear. Just don't want to have any reliability issues.

[andy01]

Are you looking at doing the hole banks kit on your Dmax? I was going to look into their complete kit but haven't found anything out yet.
Andy

[bigq]

The only major problem I see is its a Duramax.

[ZBODaytona]

I am new to the board but do have a lot of experiance with lifted trucks and towing. I would say you would want to change the gears. The durmax does a nice job, but with that much wieght and the new tires even it is going to need help. By going to a 37 from a stock tire you are really changing the overall gear ratio. You also need to be careful in finding a drop hitch that can handle the weight too....

[STV_Keith]

Assuming your truck has the 3.73 gears in it stock, going to 37" tires from stock 31.5's, it would be equivalent of going from those 3.73's to 3.18's. That's a big jump, and a huge loss of mechanical advantage.
While the truck still may pull it, it will put that much more strain on the trans, u-joints, etc. With those tires, going to a 4.30 gear would get you back into almost the same overall effective ratio (4.38 would be the exact ratio assuming going from exactly 31.5" to 37" tires).
Another thing to consider would be this...
First, I'm not sure what is available gear-wise for those front/rear ends, but even if they are available, you're normally looking at around $1000 per end to swap it out.
Second, if you ever put the tires back to stock, now it's really over geared.
You may want to consider a US Gear Underdrive unit instead. Cost-wise, it would be a little more than doing both ends, but you would be able to go under-drive to get your ratio back when towing, then go into direct for when you are not towing, and have that 3.18 ratio equivalent.
Something to think about.

[dtr352]

Buy the gears. You will regret it if you don't. The duramax has decent tourque so it will be fine but all the stress will be put on the trany. Even just driving around town you cut the life of the automatic down considerably. The gears are cheap insurance compared to a trany rebuild. Just be carefull choosing the gears. If you go to low you will wind the motor at freeway speeds which will kill the diesel. I just regeared my truck for 35" tires after a season of stock gears. What a difference.

[Lightning]

You may want to PM or ask Wes, he has the same truck with 37's and the Edge,etc....

[ADDICTED]

Okay I have a 2002 F-350 on 37" Pro-comp X terrains. Propane, Gibson exhaust w/ down pipe, 150HP BD power chip. I have towed a 39 MTI quite a few times. And towed a 26 toyhauler all the time with no problems with power. My only problem was the tranny. 10,000 miles and now on number 5. Since you have the Allison I dont forsee this being a problem. I would just lift and tow with it. Then see if you need the gears.