Gear Chatter?

Scott,

Welcome.  I also recently purchased a new Dash 8 Premier loco that is exhibiting what you describe.  First, slow speed is horrid...appears a gear is "stuck", then around 6 SMPH the loco will "smooth" out.  Around 15 SMPH....a constant clicking will emanate from the front truck.  I have greased the exposed gear and lubed up the rollers to no avail.  It is definitely coming from inside the truck.  There was a thread couple days ago about another forum member that purchased a new diesel that had the same issue.  I'm really stumped as to how QA signed off on this.  I noticed it the second I ran the engine for the first time.  Unless of course this came about being shipped a half a world away.  This diesel is a model where you can put in scale wheels, so I suspect taking the truck apart isn't too bad.  If anyone has experience with this...any tips might be helpful.  Or I'll simply drop it off and have MTH have a look see since I work 10 minutes away from MTH HQ. 

Wow, thanks. Good to know I'm not alone in this. Your experience cuts to the heart of my problem: a near new Rail King RS-3 that begins to create a very large chatter as speed increases. I've since sent it back to the supplier but am not too hopeful that he can fix it. I did notice that there was a great deal of play (side to side AND rotational) in the gears and wheels. That can't be right. I have an older MTH switcher that whispers around the track and the gears are nice and tight by comparison.

Sounds like both of you need to take the power trucks apart. Usually you can take the bottom off without having to disassemble the whole engine, although this may not be the case on some units. There could be some metal bits or something that are getting in the gears. I once took apart a power truck on a brand-new Williams engine and found a machine screw in the sump. I didn't actually try to run it that way because it also had a busted wire and so the truck wasn't getting any power anyway. And, for all you Williams worshipers out there, yes, it was NIB and still in the shrink wrap when I bought it. 

Here is the link to the scale wheels with a pdf on instructions on how to break down the truck.  Will do this tonight.  Thanks to all for the info.

This can also be the motor or driving electronic having a problem.  If the motor turns smoothly by hand and you feel no binding in the gears, I wouldn't count out electric or electronic issues.

Score! Well done ChessieMD. I had no idea that the trucks were assembled that way. Pretty embarrassing for a mechanical engineer. Will try as well tonight or over the weekend and let you know what I find.

Many thanks to all who weighed in. Very very appreciated!

John, that is actually the case with both units. Motors sound ok run separate from the trucks and no binding that I can feel in the gears. One unit is a switcher and the other an F-3. Hopefully they both have a gear problem that even a dummy like me can fix and not an electrical one.

Thanks!, S

John,

Glad you found the document helpful.  Here is an update.  I removed the top housing of the truck to reveal the wheel sets.  Very easy procedure.  I removed the center wheel that connects to the worm gear/motor, thus allowing the front and rear wheel set to rotate.  I immediately noticed that the front wheel was very smooth.  All gears looked good.  The rear wheel, however, "caught" on something as it rotated.  I then noticed a "chewed" up tooth on one of the small gears attached to the truck.  So I can attempt to file down the bad tooth, but, I have decided to drop the unit off to MTH next week.  Despite this issue it is a fantastic model with excellent sound  Again, can't believe this wasn't picked up when they did the 1mi test run prior to packaging.  Anyway, good luck!

Glad you found the problem. That is a little disturbing to find a broken gear tooth in a brand new engine. And how did it breakin the first place. Even though I just started the hobby, I have had more than a few qulaity problems with new engines.

Well, I just bought a brand new MTH FM Trainmaster. Put it on the track and the rear truck kept locking up. After some troubleshooting I found a missing gear tooth on one of the wheels which was causing the gears to jam. Pretty poor quailty control.

Ken

Also look for things like wiring or other internal parts rubbing against moving parts (like the flywheel or trucks).

I have a Williams E7 that I installed a crew cab in.  At speeds greater than 15 mph I keep hearing a clicking sound and thought it was in the trucks or electronics.  As it turned out I noticed a smudge on the back wall of the cab, where the flywheel had been rubbing.  I modified the rear cab wall and the problem was solved.

I know MTH will fix the issue so I'm not too upset over the issue.  The positive side to all of this is it has provided me an opportunity to gain more experience in troubleshooting and working on my engines.  It's all good.

I have two older MTH pieces that I got off of eBay where I will do truck disassemble this weekend. These engines exhibit near identical chatter. I suspect that it will be excess play in the overall train. The heart breaker is the near new RS-3 I got that makes the exact same noise. Just not normal for a flywheel motor engine IMO but that may be quality related as well.

Had two gear trains apart on one engine and no sign of wear or damage to the brass drive or worm gear. Found plenty of grease too. On both trucks though the drive geat axle is secured on the opposite end with a pressed on bushing or collar and there's about 0.05 inches of gap that allows side to side movement. Very excessive compared to other engines I have. Am going to take the trucks apart and add a circlip to fill the gap and see if that helps.

I have a couple of Lionel Legacy Conrail SD-80 locomotives that have excessive slop in the axles, you could slide the axles where there was almost no gear mesh at all!  I also notice that there was a plastic split washer on one of the axles to help space it, but I could not find where you get those.

My solution?

I take bread bag closures and trim them in a nice circle and slip them over the axles for spacers.  They come in a number of thicknesses, and do the job perfectly.  The even had the slot ready to slip over the axle.  You can also use a punch and make one from similar material.  I wanted black, but you can't see them anyway, so other colors are not a big issue.

Brilliant! And a perfect solution. I was getting ready to disassemble the trucks and try and jam a circlip in there. This allows me to introduce a simple spacer without any trouble and see if that cures the problem. Thanks GRJ I really appreciate the help! Now I just have to go out and buy a whole bunch of bread . . . .

Glad you like it.   If you're patient, you can get them as you shop normally.  You can buy Thomas English Muffens and they have large ones.