Replacing I-shift with manual transmission 10/13/18 ? Is it possible?

your comments make no sense.. your 2001 didn't have a automatic. It had an Eaton autoSHIFT..!

You can't go back 10 years and find people having out of warranty problems with the i-shift why because that transmission didn't even come out until 2008 model year so it would be under warranty until 2011 or longer.

 

So would you recommend 425-455 hp xe package over 500hp ecotorque .

 

Yes 100% , YES.
Look for the 1750 tq that's the key.. 455/1750 will drive almost identical to the 500 eco but with much better mpg.

 

500hp d13 has 1850ft-lbs.

 

2006 780 with ZF Meritor 12 speed auto. Internal clutch lasts 250-350k and cost $5k. Swapped with Super 10 Eaton (including adding hydraulic clutch assembly) for $6k at US Truck Parts in Dallas. Done in 2 days then stupid Volvo reprogram took 3 days.