Transmission Set Screws

Our transmission set screws are too long, did they say there were supposed to be shorter ones in there?

Does any one else have this problem?


In the video they demonstrated taking the ones in the gears out and replacing them with shorter ones that were supposedly included with the gears. They mentioned that the ones already in the gears were too long and would bind in the completed gearbox. If you do not have those extra set screws or the extra ones are too long I would ask FIRST or see if they are listed on the KOP list to make sure you ask for those by today.


FIRST said you need to replace the included screw with a smaller one, or if you so choose, get rid of it all together.

There are smaller set screws in the kit. However, they are in a separate bag, not with the transmission kit.

We found that one of our tyranny’s locked up and one made a clicking noise. Ground down all four set screws (one on each of the four motors) and problem went away :slight_smile:
They run great now.

Wayne Doenges
CAD Mentor


I did exactly what you did when I got the first production units in December. I then recommended that FIRST put the shorter screws in the kit. Your team should have 8 short set screws that came in a separate bag in your kit. Those do not have to be ground down.


Team 104 assembled our transmissions Friday night and had clearance problems with the short set screws. Filled them down. Also had problems with the spring clips. Had to remove them. We’re debating if they’re needed.


Are you sure you had the short set screws? The screws that come with the pinions are too long. You should have had short ones in a different bag. The short ones are only 1/8" long and are flush with the pinion hub. If you use the set screw, you do not need the retaining ring.


The mentioned shorter set screws are in “Misc. bag II”. At least that’s where we found them today, along with more nylon washers.

Our nylon washers fit the motor output shaft perfectly, but we had to bore out the I.D. to get them to fit over the other shafts.


We can’t tell, but it looks like our spring clips are rubbing. Is it ok to leave them out? Also, our 1/8" long set screws were in Misc Bag II and they were a tad to long, they did stick out a little. I was wondering if filing them down would decrease the sound in our transmissions.

Also, regarding filing out the nylon washers. In the Misc Bag 2, there are four that have a slightly wider whole for the two shafts in each transmission, not the motor shafts. I hope this helps. When we set up our transmissions, we messed this up and put the four larger washers on the motors on accident and had to totally disassemble both of them and switch them out.