My Freightliner actually adjusts to different weights just fine. It’s governed at 65 which is dumb but if I’m bobtailing it shifts 5-7-8-9-10-11-12, if I’m pulling an empty trailer it’s 3-5-7-9-10-11-12 and a loaded trailer is 2-4-6-8-9-10-11-12. It only shifts all 12 if I’m climbing a steep hill or I’m stuck in traffic and it’s at least half assed loaded and maybe I can get up to 4 mph for 10 seconds and then up to 7 mph and so on. So long as I let off the accelerator it’ll use the gears it normally skips in traffic or it’ll use them when it about falls flat on its face trying to climb a steep hill. What does annoy me though is how it’s geared and when it decides to shift.

It’s geared to do ~2 mph at 600 rpms in first gear but it’ll skip first and ride the clutch if I’m going slower than 3 mph for whatever reason. It’ll hold 12th gear all the way to 56 mph when 1000 rpms is 57 mph when it’s struggling to climb a hill but at slower speeds it’ll push 1800 or even 2200 rpms in 8th gear rather than shift to 9th of struggling to hold 40 mph. Weak ass piece of shit but the transmission shifts okay and it does adjust for different conditions like going uphill, downhill, 80,000+ pound fully loaded, 50,000-75,000 half assed loaded, less than 50,000 pounds down empty trailer, and even no trailer at all. It slams through the gears bobtailing and it is in high range before my back tires leave the stop line but fully loaded I bet a person could run a 100 meter dash before I’m doing 65 mph.