I took a road trip not to long ago and has been the first one i have ever taking in this truck.. Anyways i was doing about 110 - 120 km/h and it would **** into overdrive i had cruise on and it was like there was no power there it kept loosing speed and would keep kicking it back to lower gear till it got up to speed then **** into overdrive then start lossing speed again...
I am wonder why this is (i have a 4.7 auto)
and also how i can fix this... Maybe a chip or something

I already have dual exhaust and am gettin intake this week so not to sure

 

Maybe time for a good tune up???
Plugs, clean the throttle body, etc. The normal stuff.

 

hmmm ill give that a try..... not sure if thats gunna fix it but never know.. probably needs it

 

zimm my truck was the exact same way....get a set of 4.56 gears. i have a 05 4.7 auto with stock tire size. I can now climb ANY hill in top gear going as slow as 50mph! It did not hurt my gas mileage either!

 

That is what I am thinking, maybe carring a little too much weight, too much tire or not enough gear to keep everything happy.

 

yeah 3.55 gears, 5500+ pounds, and 31inch tires are not a good combo

 

hmmmm ok ya cuz originally i bleieve this truck came with 17's and im currently running 20's but didnt have nothing huge for weight... but where would i find these gears and will this hurt my low end power at all?

 

My '00 silverado had 3:73 gears and 31" tires and even that would kick out of O/D and back in..etc. It was a 4.8L and i see you got the 4.7L. So maybe similar power struggles.

 

I went through airram.com for my gears. nick is the owner and he can set you up. I had 17's originally too and i gained in every way with 4.56's. think of it like a bike, can you go up a hill easier in a lower gear or higher? the 4.56's give you a mechanical advantage (torque)

 

The stock 17" are 31", stock 20" are 33". Looks like you are running at least 33" if not more. With the engine a little off tune, it would cause a weak OD response.