As I tell everyone, YOU DO THE FOLLOWING AT YOUR OWN RISK... If you're not sure, take it to a shop.
First a question...
Are you sure the boots and clamp are the right size? Unlike personal vehicles where one size fits all commercial trucks are often vehicle specific. You can have several different sized turbos on that series truck and engine,
Use a T bolt style clamp, be careful that you don't over tighten the clamp you can get allot of clamping force quickly. Ive seen guys crack the tank openings so, go only tight enough to keep it from moving and tweak it as you go. Also use a little, JUST ENOUGH TO MIST THE BOOT! silicone spray to slide them on if they are tight fitting.
Check both turbo tubes turbo to cooler Hot, and cooler to engine Cold as they tend to rust or corrode from the inside out A corroded Hot tube can cause blockage of the charge air cooler. Make sure your cooler is not plugged, look inside the cooler do you see a powdery substance, metal, rust, or oil? a little light residue of oil is normal if its gummed up you might need to have a radiator shop flush it clean. and check the turbo for a blown oil seal if its leaking the turbo is in trouble.
Speaking of the turbo, if it has a waste gate valve I would also check to see if the valve actuator is connected and working. The actuator is a diaphragm that has a small vacuum line attached to it and connects the the turbo. If you don't see a round-ish metal piece with a hose attached to it and the turbo and a rod going from the part into the turbo your turbo is likely internally waste gated and this I would take to a turbo shop.
Make sure the line is connected, tight, and not cracked or leaking. If it checks out you will disconnect the line and start the engine just long enough to see if there is vacuum. STAY OFF THE THROTLE YOUR OVER PRESSURE PROTECTION IS DISCONNECTED!! If you rev the engine you could do some serious damage. If you have vacuum this is good sign but this also says the actuator or the linkages are likely the causes. If you have a vacuum tool you can apply vacuum to the actuator while the engine is running and listen for a change in the idle. If it changes with vacuum the actuator may be weak. I would recommend replacing it anyway as this is a common wear item and it will help the turbo do its job better.
Sometimes you can remove them and free them up and they are good to go for a while, and sometimes they are so corroded, or if the rubber diaphragm is leaking they are finished, depending on the specific turbo you can replace the actuator by itself, or you might have to replace the whole turbo.
Hope this helps, PM me if I can be of assistance.
Be Safe.
Bob Wolf..