I have an Intermountain tunnel motor and it gets very noisy when decending a grade. It sounds like the gears are grinding a bit.
Did I over lubricate?
Did I put the truck in backwards when I installed the decoder?
Do I need grease on the worm ( cannot find mine) ?
Thanks,
It sounds like the worm gear(s) have too much play in them. Remove the top cover off your trucks and check to see how much end play is in the worm gears. They make shims for this. You may also have a chipped gear on a spur gear. The weight of the locomotive keeps the backla***ight when going uphill, but when going downhill, the lash is alternating between loose/tight, and if there is a missing tooth, one gear is riding over another.
Loco makes noise when going forward down hill. Does it make the same noise when backing up? If not then it’s not too much slack in the worm gear. May be just normal gear noise. All gears operate with a certain amount of slack or clearance. As long as the slack is taken out of the gear train, it’s quiet when pulling in either direction. When going down hill, it may be that it’s at the point that the loco is neither pulling or holding the train back, thus the slack in the gears allow them to chatter. We encounter the same thing on our Rotax powered airplane when taxiing. A certain rpm the gears in the prop drive chatter so we adjust the power to stop it. Just a thought. I have an SW900 switcher that did the same thing. Wasn’t gears but the motor clearance was so little that it rocked over against the body shell. Might try removing the body and see if the noise is still there. Ken
Good answers. Lube the gears with grease or heavy oil (causing them to “stick together”) and see if this reduces the noise. This will not fix the problem but will show it is in the gears.
Where do you get the shims for the excessive play in the worm gear?
Get nylon or fiber #2 washers. If you can not disassemble the gear box to install them here is a way that works for me. Cut a “V” in the washer making sure the root of the “V” is smaller than the shaft. The washer can then be snapped on to the shaft from the outside. If a worm gear is being shimmed divide the washers on each side so the worm stays centered.
nedthomas,Thanks guys. I have the heavy grease but cannot find( so I guess I dont HAVE it), will try this first.
Eirediamond,Will try removing the body and running.
Thanks for the washer idea. Where do I get them?
Kadee sells fiber washers in packs of 48. Walthers lists them in brass.