This the truck working on a body lift

 

Well you need to see if your plenum gasket is blown. There is a sticky thread at the top of the page about your plenum.

Next is you need to regear your axles. I would go with 4.56 or if you can find them 4.88 gears. You'll be shocked at how much better the truck drives with new gears.

 

Trucks are undeergesrd from the factory with the 3.55s. Personally I think all should have been 4.10s. At least with the small blocks. Diesel and v10 is different because of their gobs amount of torque.

 

I agree with Wildman if your gonna run that size tire. Your only option is gear change. 3.55s are ill equipt For that. I run 265 75 16s on 3.55 and I'm not impressed even thou mines a 360. Especially hauling a max gvwr trailer. In the process of going 4.10s soon

 

When I hauled this heavy toy it did great but when I hauled the trailer empty it didn't

 

Where can I get 4 10 gears

 

You can get gears just about anywhere you get other parts. Jegs, Summit, local parts store, etc. Randy's Ring and Pinion is another good source.

Stay out of 5th gear when towing anything.

 

I agree with wildman! Your running 36's with stock axles man!! Those are big heavy tires! Even 33's are big for that ratio. Running 33's you should have at least 4.10 much less 36's.. Not to mention the heat your transmission is producing and dealing with. Swap out them gears for sure