Is this even possible?
when I run the engine on the bench and mark the wheels with white paint it seems they are at different speeds.
the engine is a lionel, FT diesel, with TMCC.
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Not that unusual, it would be more unusual for them to run freewheeling at exactly the same speed. Even I slight difference in the friction within the drive train for each truck is enough to radically change the freewheeling speed. For those with Odyssey cruise control, the effect is even more likely, only one motor provides the feedback for the speed control.
They work fine on the tracks, just make sure both motors and drive trains are free of binding or excessive friction.
if not checked properly yes as it is very possible 2 motors to run at different speeds could fall from different things thou it could be the motors but that would be more common I would think with the old ac motors than the newer dc also could be in the electronics also
Since the motors are wired in parallel in virtually all of the command stuff I've ever seen, the electronics isn't going to enter into this equation. 
Thanks for the quick replies.
by tracing the wiring, it looks like both motors should see the same output at the same time. So if it is most likely not the electronics I will check for binding in the trucks. BTW the motors do not have flywheels, so I am looking at the drive wheels.
Thanks again
these are not synchronous motors. You should have no problems.
romiller
In a free-wheeling, no load setup on a test bench, I doubt that you would ever find a dual-motored loco where both motors ran at exactly the same speed. But the point is...they don't have to!
When running under a load, each motor will take up its share of the load and they will run together just fine.
Absolutely possible, but nothing to worry about. The most important part is keeping the locomotive's drivetrain clean of debris and properly lubricated. Any poor performance is usually traced back to improper lubrication, rather than motor performance. Modern DC motors are maintenance free, but AC motors will need periodic tune ups, such as replacing the brushes and adjusting the brush spring tension.
-John
What our Webmaster says is true to a large extent with postwar Lionel diesels (which had back-drivable series-wound AC motors.) But in their service manual, Lionel advised that for best operation, both motors of a dual-motored F-3 should start within one volt of each other.
In your case how significant is the difference? Unlike newer Legacy diesels and the old postwar greats, your Lionel FT has self-locking worm gears on both motor trucks. If the speeds are off, your loco might start out with a lurch. If one motor is defective, one or both motors may tend to run hot, and will eventually fail or cause premature failure of the electronics.
The difference you're observing in wheel speed might not be between the motors per se. Even when the loco is "freewheeling" on a test stand, there is still friction from the gear mesh between the worm on the motor shaft and the worm wheel in the truck. At least one generation of Lionel's FTs had improperly meshed gears, which could be corrected by shimming. Search my other posts for more info on this subject.
If the loco (1) starts smoothly; (2) doesn't draw excess amps compared to your other diesels with two can motors; and (3) attains a reasonable top speed (let's say 75-80 scale MPH at 17 volts) then both motors and gear sets are probably healthy. Hope this helps! -Ted
