I just took my new M923 for its first spin. I got it over a week ago, but I haven’t had time to play with it on weekdays, and I did a bunch of little stuff to it first like fixing some air leaks behind the dash, installing the cargo cover kit, adjusting tire pressures, cleaning windows, and so forth. I don’t have it titled yet, so I just stuck to the dirt roads around where I live.
I found that I have a lot of trouble changing the transfer range when stationary. The lever easily pops into neutral, but then I have a hard time getting it to engage either range from there. I can hear the small air dump when pushing the button on the end with the engine off and the master switch on, and nothing suggests to me that I’m having trouble with any of the interlocks. It just seems to be hard to get it to engage either gear. I’ll need to look into this further. I haven’t tried changing transfer range while rolling yet. Low range is fine for my local dirt roads, unless I need to stop and back up; then I’d need to get it back into high range before shifting to reverse.
On some of the worse bumpy parts, especially when braking, the truck started bucking like a bronco. I’m not sure, but it might have been the ABS doing its thing? I got well-acquainted with the bottom stop of the spring ride seat, and I think I may install a rubber bumper there to keep it from slamming down so hard. 🙂 Maybe I just need to crank the spring adjustment tighter, though. I wish the seat back would lean back a bit farther.
The power steering sure is wonderful when making tight turns at low speed!
Rolling out of my gate on my fairly steep and rough driveway, I actually ran the truck low on air. I think this was partly due to having the truck in high range, the engine RPMs at idle, and feathering the brake a lot. I think this will stop being an issue once I smooth out the transfer linkage and get the hang of being in the right gear and range. It’s been a decade or more since I’ve driven anything with air brakes, and I expect that I’ll need to recalibrate my foot and learn how this truck likes to be driven.
Unladen, that 5-ton can be a rough ride on my dirt roads. I wonder whether 2-3 tons of knuckleboom on the back will make that better or worse?
This was my first time driving an M939-series truck, and it was fun! For that matter, it was my first time driving a big truck with an automatic transmission. I like it a lot better than a stick-shift in off-road driving, since I grew up with auto transmissions and I’m just more comfortable with them. It’ll still take a bit of practice to learn just what gear ranges my truck wants to be in on hills.