This model I got from the SpinTires Mudrunner game and edited to the 3D printing. It has 1/14 scale and RWD from JJRC Q60. Because I have a lot 4WD models, I wanted some RWD car to get more experience and difficulty on the ride. Body printed from ABS and glued together with ABS juice. I made tyres from a silicone sealant using a 3d printed mold. It came pretty soft and heavy (because solid). I have recommended using a black aquarium sealant because it is black and has not shrink like a regular colourless sealant. Also you can printed tyres from some TPU flex plastic. I made rear wheels is wider by increasing Z scale up to 120% in the slicer for tyremold and wheel parts.
JJRC Q60 rear axle
TT gearbox
130 motor replacement
SG90 plastic servo orMG90S Metal servo
623 bearings
Black silicone sealant
Leaf springs
ESC for brush motor
2S battery You can use any 2 channel RC tramitter. I have used Flysky FS-GT3B but also tried cheaper and more functionaled DumboRC X6 There is an old Chevy truck with rear drive and open diff. It run on the yellow TT al motor quickly died and replaced. Also I removed one gear step to increase speed. 623 bearing put iide the hub and may glued carefully if it loose. Hex axle screwed through bearing with M3 screw. Cup part fixed with a screw on a gearbox shaft and a driveshaft's end mounted with M2 screw & nut iide a cup. From other end you can used a metal pin from old JJRC driveshaft or M2 screw too. Leaf spring puts on chassis with M2 screws and folded ends hold on chassis by a piece of paper clip spring's end must be slide under wire when spring is damping.