Fox Valley GP60M squeaking sound

[ATSF_Ron]

I have 3 Fox Valley GP60s.  My one Santa Fe GP60M is a squeaker.  The other two GP60s have been fine.  I've had it since around 2017.  It squeaked in reverse only when I first got it.  Watched a video from a guy on Youtube (can't find it now, naturally) on where to lube to remove the squeak.  That fixed it.  As near as I can remember, I lubed all the areas mentioned in the video.  Worm gear, truck gears, and drive shaft/bearing points I could see or access.  A couple of days ago the squeaking resumed.  I've relubed everything and the damn thing still squeaks.  In reverse only.  I also loosened the screws that hold the two frame halves together, as they were super tight and I figured maybe that contributed to the problem.  No difference.  The squeaking happens only when speed goes above about 20 smph.  This is a puzzler.  Even more weird since the initial lube solved the problem.  I've read these can be either overlubed or have almost no lube when delivered from the manufacturer.  Does anyone have a suggestion on what to do next?  Anyone have a similar problem?  I've looked at the mechanism running up close with my optivisors on and can't see anything rubbing that shouldn't be...


Thanks,

ATSF Ron

[milw156]

Yes, but with an ES44, both directions and only above a certain speed step (i have mine programmed for mad speed of 60-squeeling starts about 25smph)

[tehachapifan]

Sounds like what at least used to be called the "Kato screech", but it can affect other manufacturers as well. The typical culprit is where the worm/flywheel shaft(s) exits the motor. I believe that, when this bearing becomes dry, an extremely rapid vibration will begin at a certain speed due to friction and can cause the terrible trademark screech.  This screech is also often accompanied by visible loco slowing. The remedy is applying an extremely tiny amount of oil to these bearings (I use LaBelle Lite oil). I do so by placing a tiny drop on the end of a thin wire (.008 or so) and then touch the wire end to the bearing. Too much oil can seep into and foul the motor, so be very careful! Sometimes the source can also be coming from the worm bearings.

[peteski]

It is likely the fastest rotating shaft (motor and worms).  Usually it is the motor.  Make sure to lube the motor bearings.

If you feel like doing some work, swap the motor from the squeaker to another of those locos and see if the squeak follows the motor or stays with the original chassis.

[tehachapifan]

Why didn't I think of that.

[ATSF_Ron]

Thanks for the replies.  I'll piddle with it more on Sunday and see what happens.

[sizemore]

Motor bearings. Always.

The S.

[DeltaBravo]

I am with @sizemore on this it almost always the motor bearing.

[peteski]

I believe at this point it's unanimous - we all recommend checking/lubricating the motor (and/or worm) shafts, since they all rotate at the same (fastest) speed.