New MTH engine making grinding noise

I find this type of post very interesting , makes you put your thinking hat on, however I'm coming up almost  blank. 

  jammed traction tire .bent axle , center rail rollers, loose  truck screw, Where's the tack reader? front or rear truck  ,  timing tape rubbing?   Did you try turning the flywheel by hand with truck attached?   Iron filing down in worm gear?

If you bought it from an MTH dealer, I'd have the receipt in hand and call MTH.  Let them fix it under the warranty.  If you bought it from a friend, you have a mechanical problem.  The loco shaking from side to side could be a bent axle or a traction tire issue.  If I had it on my workbench, rather than take it all apart, I'd test one item at a time, to narrow the range of possibilities.

If it still has the shell off, remove the motor from the truck, and check the two screws that hold the motor mount to the motor.  While you are there, spin the motor by hand and see if it turns freely. Make sure there is a some grease on the drive gear, and the truck gears. Eyeball the driven gear in the truck, it should appear to be in the center of the axle shaft. The grease and truck should not have any brass powder/filings in them, if so there is either a truck problem or a motor problem. Keep us posted. 

I bought it at a show and paid cash so I didn't get a receipt. Never going to do that again! It was new from Gryzbowski. 

It can't be an issue with a bent axle. I switched the front truck with the back truck. The front truck doesn't have any problems with the back motor now, and the truck previously fine on the back now has an issue with the front motor. I'll check for debris in a few, but it's brand new so I wouldn't imagine there is any

So the problem is with the front motor?  Did you check out the 2 screws that holds the motor to the motor mount as  Luke suggested? Maybe that's it.

Run it with the body shell off. Could be your flywheel is rubbing the inside of the shell. When you lift the locomotive the motor and truck is dropping down and not rubbing anymore.

It does the same thing with the shell off. I switched the motor mounts between the front and rear motors. All screws are tight. Now it makes the noise going both forward and backward. The rear now has the original front truck and front motor mount and still makes no noise. There's no debris in any gears. Everything has plenty of grease

Also, the motor does turn freely and it doesn't make the noise when running with motor completely disconnected from the truck

One other thing to note, the noise is kind of a pulse, not a constant grinding 

Smoke unit?  try turning it off.

I haven't turned the smoke unit on yet. Pushing down on the frame it makes the noise when in reverse, and pulling up on the frame it stops making the noise when going forward . I'm almost thinking it's something to with something being too low. Naturally the motor is being pulled down by the gear when going forward, pushed up when going backward. So when going backward it makes no noise. As if going forward something is scraping. It's happening between the main gear in the worm gear on the motor shaft. I can't see those 2 parts moving though because there's no way to look in. 

It's a 3 year old engine, which I purchased new, but I didn't get a receipt. I got it at a show so I doubt the dealer remembers it. And the dealer is 4 hours away from me so I can't go myself. Not sure if I'd be able to send it to MTH and have it fixed for free.

Does it do this with shell off?  Pull motor and compare to other motor, measuring worm.  Are you sure not previously repaired?  The motor will thrust vertically depending on direction, so you can have an issue in one direction and not the other.  IS the bottom of the worm showing signs of metal to metal contact.

Grinding is metal to metal not metal to plastic, so is that what you hear?  G

So, if you have a gear or gear alignment problem.......Can you look at your amp draw  and compare that reading while going in reverse and then forward. I would think if the gears aren't meshing correctly your amp draw would be higher in one direction due to more resistance. (assuming you have a z4000 with an ammeter or similar xfmr with a meter)

 Also, something I never knew until last year when sending in 1 of my locos for repair. Apparently, sometimes it is necessary to shim a motor to get the alignment with the truck gear correct. I had a premier loco that when going up a hill would spin the motor but wasn't making contact with the truck gear. It made a horrible noise. The tech called and said He was going to shim the motor. I was thinking that a new motor was needed. But He said this is a common practice and the worm gear still looked fine. Maybe you need some shimming.

One more thought.....you stated in your original post that you bought this as a new loco. When ANYONE (dealer or not) tells me new, the first thing I do when I power up is to check the info for the locomotive with the handheld. Those readings cant lie. I would think (cant say for sure) that the person that sold it to you would remember you. He should be able to get you a receipt. Call them and explain it to them.

Call Grybowski. They are a reputable dealer and should help you.

romiller

Haven't had a chance to mess with it in a while (been at school) but just started experimenting with it again. What I've found is that the truck rocks from front to back and the frame rocks side to side. Almost as if it's oscillating. The grinding noise is in sync with that. So something is making the truck rock which is then causing the grinding noise I think.

I liked the shim idea and tried a bunch of different shims between the motor and mounting bracket. I've got it so that it runs perfectly smooth in reverse but rocks a little going forward. Not as bad but it's still a noticeable problem. I'm thinking it might be time to just send it in but I prefer not to if I don't have to.

Trevor

What is the scale mileage and chrono reading on the DCS remote?

PAUL ROMANO posted:

What is the scale mileage and chrono reading on the DCS remote?

I'd have to go and check tomorrow but it's going to be pretty high because I've been testing it for quite a while