Instructions for removing and replacing H237 offset gear in T-Rex Jr.'s         

  Tools Needed:

  • Philips screwdriver
  • Rubber mallet

Step 1: Remove the screws holding the bottom transmission plate and gearbox together (Figure A).

Step 2: Remove the plate off the transmission. If it

binds up on the shaft, gently rock the plate as you pull

it off (Figure B).

Step 3: Remove rubber gasket from gearbox - set

aside for reassembly (Figure C).

Step 4: Remove the offset gear (smaller gear) - it

should lift straight out (Figure D).

Step 5: Before installing the new offset gear, fully coat the new offset gear with blue lube from the motor box

(Figure E).

Step 6: Install the new gear (Part # H237) by pressing back into place by hand. To ensure that gears are straight and engage with one another, twist the gear by hand to make sure teeth are aligned properly. (Figure F).

Step 7: Replace rubber gasket. Make sure holes are

aligned (Figure G).

Step 8: Re-install plate. You can tap down with a mallet if needed. Replace the screws with a Phillips head screwdriver (Figure H).