I bought my first ctd 4 months ago and I'm just trying to figure out if this is normal for a stock truck or not, it's got 400 000 km and I got it from the original owner who said the trans is original and so is the vp44. Lift pump is new and pressure has been checked
The truck now has 4 inch straight pipe and bhaf
It pulls ok at low rpm but feels like there is a power droP around the 2200 like it has the same power as 3/4 throttle and the rpm contine to climb but it's not pulling as hard. Is this posibly just the gov starting to de fuel as its not chiped ? also under any more then 1/2 or so throttle it seems to pull the same like 3/4 throttle feels as fast as full?
Also I'm guessing it's my trans as its stock hi Milage but on hard full throttle acell my rpm just go up to 3000 or so and almost stay there you can feel the shifts but there's not much of a rpm drop until 3rd lock and 4 th
I'm a mechanic so I know what a slipping trans feels like and this dosent feel like a slip that I have felt in a gas vehicle ( don't work on many diesels)
I like the truck just trying to figure if this is normal and I need to build the trans and chip it or there are problems I need to look into

 

It wont be defueling 2700 rpm if its all stock, and most chips will only fuel up to 2700. As for the low power in the higher rpm i have not a clue.