I have T tamiya Tiger I with maybe the second generation trans unit, this trans unit has the brass extended shaft that secured to the main shaft by two 3mm grub screws. The question I have and I did not notice them until each unit was completely cleaned and I was returning the liquid into a holding container. There was a small flat thin washer each time that I did not see with all the grease as I separated each part for cleaning ,One shaft at a time.If some one could give me the were a bouts this washers belongs I will be grateful. I will post a picture later if needed @ this time I have the battery on charge. thank you