This is a mod I use privately but I figured I'd make public. I find the M916A1 is a cool truck with among the shortest wheelbases of the class, but because of the stock tuning I don't find this truck much fun or very useful. Other trucks can do everything the M916A1 does and do it better. This is my attempt at correcting that to make this truck have a place in the stable with other great trucks.
The steering is corrected by adjusting:
Steering rate & responsiveness.
Maximum Steering Angle is increased to 42 degrees.
The stock truck does not include steering joint offset, which is unfortunate. This mod adds some minor steering joint offset which combined with the caster and other changes, makes the steering functionally much better.
The drivetrain is divided up with the rear axles split. The forward rear-axle is normally disconnected, and engages with AWD. AWD toggles from 4x6 to 6x6. The forward rear-axle is also raised ever so slightly relative to the front and rear. This has the effect of reducing unloaded traction on the forward rear axle (think like a dump truck with its extra mid axle set raised). This reduces the tendency of the truck to suddenly understeer and push due to its short wheelbase. I've put both the AWD and Diff Lock as selectable, and it can be operated in Low range locked 4x6 or locked 6x6, and normal range AWD 4x6 and 6x6. Some vehicles with Always-On AWD and Diff lock take a bit of the fun out of driving I find. Toggling your own awd/diff lock adds an element of effort.
The Center of Gravity is also moved slightly forward, and slightly down to increase weight on the front wheels helping to make turning more predictable.
Front steering axle is moved slightly forward for better approach angle and a bit less dirt nose diving.
The Low Saddle is moved rearward both to counter the CG adjustment when loaded, but mainly to provide more turning clearance, the high step deck 5 trailer will just barely turn past 90 degrees although it will bang the hoses a bit. The flat and boxside 5's turn nicely past 90.
The High Saddle is moved forward to allow more trailer weight on the middle and front axles.
The Stock suspension is tweaked slightly, more damping, a bit softer, and a bit more wheel range.
The Raised suspension is a bit firmer, with a moderate damping, and the most wheel range.
Additional real mud tire choices are added:
The P16's OHD-1's have been added, as have the Tayga's.
Both the P16 & Tayga's are modified to be consistent with the rest of the tires for this truck, meaning a Medium weight, and Firm stiffness, many addons forget to adjust the tires appropriate to the truck. They behave exactly like the rest of the double tires, except they have appropriate mud modifiers. The Tayga's are of course the best in mud with the best modifier.
The stock small size is maintained, the large size is 50". A larger tire is possible but then it visually looks weird especially with the mudflaps. Plus I don't think the M916A3 should replace like the P12 or P16.
Fuel Capacity increased modestly to 280 although efficiency of engines unchanged except the Westline V12, tuned to be consistent with other engine gas usage steps.
Some folks like their trucks slightly over-powered... or really over-powered. To accommodate I've added the Westline V12 although it really is unnecessary.
Lastly, I added a non strobe fog light bar for the roof. I actually left in both sets of beacon & fog... with the caged beacon you can have 5 beacons on the roof if you really want that wide load feel haha.
V. 1.0.3 adds a single slot sideboard box! Special thanks to @emilhetty for creating the mesh & files for this!