The roar you hear i the fan coming on, there are 2 things that can make the fan come on/1-coolant temp/ 2-oil temp.
I think you are going to find out that you oil cooler is clogged and the oil temp is going so high that the fan kicks on and it will also defuel the motor to keep itself from burning up, that is what is causing your lack of power. Have you mechanic monitor engine oil temp and engine coolant temp, if they are more then 15 degrees apart then the cooler is clogged, a coolant filter added to the system will help kep that from happening again. The test should be done once it is at operating temps and you will have to put a load on it, towing uphill will definately work, the oil temp will be higher because the coolant is used to cool the oil but the oil temp should be within 15deg. in the worst possible scenario.

 

Stock gauges are not gauges... they're more like idiot lights. Get some real gauges on that thing. Especially since you tow heavy and often it seems.

Something like an SCT livewire TS, or an Edge insight CTS for a pod, or if you want stand alone gauges I use Isspro EV2's. For you, I'd recommend fuel pressure, ECT (engine coolant temp) EOT (engine oil temp), and maybe either pyro(EGT's) or a trans temp, your pick. The first three are the really important ones.

 

Found a highly recommended high performance Diesel mechanic who moonlights in his own garage. He even owns an '06 6.0 litre himself all tricked out for racing.
He wants to:
1. Road test pulling 3 tons
2. Test oil cooler for restrictions
3. Clean turbo
4. Install EGR bipass kit
5. Remove catalyst canister
6. Install and program performance chip and make sure the power loss is cured
7. and negate any factory extended warranty

total cost is half of another 2 yr. extended warranty.

Well, sound good? Or stick with another extended warranty in case other things die: transmission, transfer case, axles, fuel system components, computer, along with peace of mind. I'm listening.

 

Spend the moneyon fixing all the stupid factory issues and you wont need a warranty. The Stock trans is one of the toughest trans on the planet, once you fix the weak links they are a very good truck.

 

I would do what he's suggesting, except I wouldn't add tuning until you figure out why it's low on power FIRST. Once you're sure you've got the gremlins taken care of, then add a tow tune too.

I'm assuming this guy knows you should be using SCT's with custom tuning only, but just want to make sure.

 

Good news guys,

I rode the beast with the trailer real hard down country roads for about two hours. I did many standing starts to put a big load on the turbo. Bingo!!!! A code finally appears pointing to some actuating ring that plays with some fins inside the turbo. The dealership can now replace the turbo free of charge!!!!!!!
After that, I will go back through the Smokies for the real post-repair test. The repair warranty should cover problems without having to re-up on the extended factory warranty.
The EGR kit will be done in April following a hot return trip from Florida.

Also, turns out a close relative is a very big cheese at Asheville B-W for after-market turbos.
He offered to send me their best replacement for Christmas. Makes my Diesel mechanic drool. How lucky can you get?

Pictures below show you why I love my truck and want it running right

Thanks guys. You've been a great help. I'll keep you posted.