The bands have not been adjusted, i just pulled it from one truck and put it in another.
and to answer RWB I did put larger tires on it. but had the same size on for a time after all the work.

 

Take it to a speedo shop that can check it in the truck, or a dyno that can do mph, or even see if you can find one of those radar signs that tell you how fast you are going and check your speedo. If it is correct then you will have to start with the tranny or torque converter.

 

the speedo is a little off just like 5 mph tho. I used my GPS to check it. if that's what you're talking about. and the tranny does not slip as far as i can tell.

 

Did the truck still go as fast before the tire change, and after the tire change? Or did the truck slow down after the tire change?
I'm just trying to eliminate the obvious.

 

tires change didn't do much of anything. it was slow before i put the bigger tires on it.

 

Then it is either the torque converter or your tranny, Your not doing this in 4x4 I hope which would be a big problem.

 

yup its in a 4x4. why the big problem.

 

In 4x4, not a 4x4.

 

It's 4 wheel drive all the way

 

It's full time 4x4? IE always in 4x4. Either way it is probably your tranny not allowing you to go faster.