Nearly all of Technic Sets have minor or big Bugs in their construction. The 42099 too Low Clearance below the diffs Wobbly Steering to fast to climb The big Turntable in front
Ground clearance Front: before 3,5Studs, now 4,5 studs Back: before 5 Studs, now 6,5 Studs
Crawling: Now the reduction between Motor and diff is 1.4:1. Before it was at 1:1.985. The space for  3.89:1 is available
The Frame is changed a bit to move the battbox a little bit forward and lower the center of weight a bit.
Turntable a vid for the the fixed steering will follow