I'd dont get where this thread has gone. Where did not shifting come from ? Why ? How does maintaining a particular speed have anything to do with not shifting ? Fwiw sprinter's have a 6 speed auto and if operating properly you shouldnt feel when it shifts.
I guess this talk of pulling grades depends on your definition of a grade. The Cummins makes its max torque @ down around 15-1600 rpm so yes it will be happy in top gear cruising.
Most interstates are limited to 6% with exceptions to 7% in mountain areas like Colorado.
John has shown the Cummins has the torque to pull a 6% grade but that depends on a myriad of things like tire height, weight, gearing etc. I stated several times the first truck we built was a purpose built off road machine. No I havent driven it 75 mph, I just dont want to go there. It has 12.5 x 35 directional mud terrain tires 4+ inches of lift and slinky suspension, full external cage etc, 4:10's with lockers etc. I have no doubt it will do 75. The Cummins gear ratio calculator showed the truck shifting into 6th gear around 88mph.
If you have climbed some of the Colorado passes on I70 you know some of those grades are 12 miles long. My 2000 F250 with a fairly modified 7.3 computer controled powerstroke doesnt pull those grades without shifting.
HP and torque specs for the current 3.0 liter diesel sprinter van that you guys are holding up as a litmus test are 188 hp, 325 lb-ft.
Those engines are Tier (2010 and up) 3 diesels. The Cummins 2.8 is still the desireable Tier 1 (pre 2004). Tier 2 was 2004-2010. These tiers are emissions standards required of manufacturers. Retrofiting a Tier 2 or 3 diesel into a defender would be daunting. I personally wouldn't want to retro fit anything that requires DEF.
Personally, I think these are awesome retrofit engines for defenders. Having gone back and forth with Dave Ashcroft he feels strongly that the latest itteration of his r380 stumpy with HD bearings will hold up well to the R2.8.
I hope so, he's building me three that are supposed to ready to ship Friday.