Guys, I would have to agree that Athearn RTR AC4400 suck! Mine only lasted 3 times around the club layout before it started making all kinds of noises. I took it home, cleaned it up and lubed it and the noises level came down but did not go away. Now I just don’t care to run as much and I am totally hesitant to buy another RTR from Athearn. Maybe it was just a bad apple.
WoW! I was almost sure they would be like the RTR SD50’s and use the old white rubber motor mounts. Thanks for the answer.
The RTR SD50’s have the red nylon worm gear. Are these red worm gears installed in the AC4400, or are do they have the brass worm gears? The reason I ask is that I’m not really a fan of the new red nylon ones. I replaced the nylon gears with the brass ones in my RTR SD50 and what a difference it made as far as operation.
NS, I’m 95% sure it has a brass worm gear. I can check tomorrow.
I have another theory on why the motor makes so much noise. The armature or flywheels may not be balanced perfectly, causing a lot of vibration to go through the plastic motor mounts, making a lot of noise. You can check for vibration by running the motor only and holding onto the sides of the motor. If the motor is what’s off balance, than it could probably be quieted down by replacing the plastic mounts with white rubbery mounts. Here’s a link to the white mounts:http://www.athearn.com/Products/Default.aspx?ProdID=ATH84020
Or you could simply replace the motor with a P2K motor and somehow mount the Athearn flywheels to it.[:D]
One way to tell if the flywheels are off-balance is by taking them off the motor and seeing if the motor still vibrates. If it doesn’t, then you can balance the flywheels by looking for the spot throwing it off balance and drilling small holes until they don’t cause anymore vibration. This is how I balanced the flywheels in a lot of my Athearns.[:D]
Athearn doesn’t use brass worms in their above BB quality diesels anymore, but they still make them.
I hope this all helps.[:D][:D]
The flywheels are balanced. I’m going to lubricate the motor bearings sometime and I’ll let y’all know if it helped.
@ Darth Santa Fe
I have an Atlas U30C that needed the motor mount screws tightened because it made a lot of noise, so your theory probably holds more water than mine. I have a couple of BB Athearn C44-9W’s that have no problem what so ever with motor noise, so fitting the new RTR chassis with the white rubber mounts is a good tip.
I really wish Athearn would do away with the nylon worm gears, period. [xx(]
The motor on my Atlas U33C was so loud I had to tighten it. Now it’s nice & quiet[8D]
I wish Athearn would jump off a cliff at this point.
I do have 2 BB -9s which I love. The only unusual noise I hear from them is when they go around a turn. This is all 22" radius. It is a very platic like clicking. doesn’t sound like the motor but who knows.
I am pretty sure it has something to do with either the gearboxes, splines, or perhaps the wheel distance is out of spec. If u have ever had anything like that or could speculate on the problem let me know.
Dan