Shell Rotella T6 15w-40 vs Rotella Gas Truck 0W-20, 5W-20, & 5W-30

Stover, MO
Not trying to throw out anything that might have been already but wanted to get your opinions on these changes.

I'm in the speculation that Shell is in the process of reorganizing it's HD product lines as our vehicle purchases have shifted. As we all have seen the 15w-40 T6 replace the 5w-40 T6 on the retail shelves. I'm beginning to think that in order to position the T6 for HD Diesel market they've changed to 15w-40. A very common HD Diesel weight. They've positioned the T6 to also not be the go to for gas engines with the ck-4 change api specifications?.

Trucks & SUV's are the new craze & with the oil cost at all time lows this was expected. This trend will continue to follow low gas costs. So, they knew they were going to position the newer HD Gas Engine Oil option in order to differentiate the 2 HD Oil markets.

I'm in a firm believe this change is good as they will recipe the oil for Gas a bit different than diesel. We all just don't throw 30 Weight in all our motors anymore. ha ha

What say you?...
The T6 was always geared towards the HD diesel market. According to their site, they have T6 in 0w40, 5w40, 15w40. Retailers will only stock what they know sales. So I really don't know why eliminated the 5w40. But yes, I agree 15w40 is a popular weight for HD diesels. I think Shell Rotella is trying to serve there customers with what is out there. No longer would todays HD diesel and gas engines call for the same weight. My guess is that why they drop the dual rating on the HD oils, except for the 5w30. And then they come out with a Gas Truck oil in the most commonly used weights for there customer gas engines needs.
Greenville SC
I used (2008-2016; quit riding) 5W40 T6 in my motorcycle. It had the JASO spec, and cold morning starts were (at least SEEMED) better than with 10W or 15W products.