Looking for this?
Team Associated RC18MT
And I found this as well. RC18T owner, now you can convert it to MT.
Can I convert my 18T to a monster truck?
Yes you can. You'll need the following parts:
#21065 18MT Wheel/Tire/Insert, mounted $17.99
#21063 18MT Chrome Wheels $ 7.99
#21064 18MT Tires and Inserts $10.99
#21072 18MT Body, flag design $17.99
#21075 18MT Body, clear, with masks and decals $11.99
#21076 18MT Decal Sheet and Window Masks $ 3.99
#21129 M3 x 5 BHPS (motor screws) $ 1.99
#21210 Super 370 Motor $11.99
(must use #21129 screws to mount)
#21152 10T Motor Pinion $ 3.99
#21239 18MT Flag Kit $ 6.99