@Ted S posted:@JohnActon I've been off the Forum for a while and just came across this nugget of wisdom. I have a couple of these switchers. Can you share some details of what you swapped, or where you got the parts needed for this mod? Thanks!!
Ted, the stock gears on the upper gearbox for the B6 are 32 pitch and it would be impossible to achieve a 3:1 ratio using them since the spacing between the motor shaft and the shaft from the prime gearbox is not adjustable. I have a box of brass 48 pitch gears from slot car days. You can find them new on eBay. The original 32 pitch gears used a brass 9 tooth pinion on the motor shaft and a 19 tooth nylon gear on the shaft coming from the main gearbox on the middle axle. Attached is a photo of the B6 with TMCC 4 chuff smoke and Railsounds 2.5 in the tender. The brass gears that I used were a bit noisy and tended to sling grease around. I made a brass cover for that gearbox so I could run them in a wet sump with a homebrew grease of graphite, sanding dust from an oily tropical hardwood and Slick 50. The stuff clings to the gears like crazy and is self leveling if you put a drop on a sheet of glass it will flatten out over night but slow so you cannot see it happen. So unlike stiff grease it flows back down to the sump so the gears never run dry. Initially I used an LCRU2 for TMCC control however I pulled it out when one of the coupler triacs died and replaced it with an ERR AC commander which luckly fits in the same space. Without pulling the thing apart I am not certain of the teeth count but it is a multiple of 3. 8/24, 9/27 or 10/30. This was the first mod I did to the B6 when I bought it back in 89. I remember that the small pinion had very little space to drill a hole large enough for the Pullmor motor shaft. I have some very fine jeweler files and think it was an 8 tooth gear that I slipped on to the rat tail file. I spun the gear riding on the file with a rubber wheel in a dremel tool. There was very little space between the hole and the bottom of the teeth and I was afraid that a press fit would split the gear so I decided that I would solder it on. I reamed it a couple thousands larger than the motor shaft so it was a difficult push on but did not require tapping with a hammer. I could have held a file against the motor shaft and turn it down however that would have prevented going back to the original gears. Attached photo of insides of B6. You can see the brass cover I made for the upper gearbox on the front side of the motor mount. j
