Ok, One more question for the engineer guys.
I know a lot of work has gone into the transmission and I understand some of the reasons why it may be so (a mechanic that also spent three years as an engineering department quality assurance inspector at a transmission factory in Australia).
This has to do with the tow/haul feature, when towing our 26ft travel trailer, trailer and water/load etc (including weekend bagage for one wife and two daughters....) equals around 5500 lb's, I'm pretty happy with the way the truck pulls it, except when sitting at around 90 - 100km/hr we hit a bit of a rise, and instead of easing out of lockup, back and then holding 4th (not labouring much, hardly seems it's working hard at all), when it hits 80 km/h it drops back to 3rd, and the poor engine is running almost 4000rpm a jump of around 1,300 rpm, so I back the foot off, let it run at 70km/h until the road levels out and then it decides to upshift which is a fairly long 1-2 seconds, kinda reminds me of the old Gm powerglides when they were worn, however on subsequent trips on the same road and other similar grades (not steep) I drop it into normal shift mode and she pulls up the hill no worries in 4th and even 4th TCC lockup.
(Yes.... I can hear you all.... you know who you are.... you Diesel guys with the 2 story tri-axle 5th wheels that round me up doing 130km/h....
Now, is this because the shift patterns were designed for the possibility of heavier trailers than what I'm pulling??? If so, are there any worries with me just leaving it in normal mode, which then becomes a bit painful because it presumes I'm not towing and the MDS and 5th TCC lockup plays havok as they come in and out all the time.
I've learnt to drive it between the two and doesn't worry me that much, but am still curious.
Cheers all and have a good meeting