Gearbox vibration in a live axle setup, is this a problem?


Looking for some comments from people who have experience with live axle drive systems.

We are powering our drive wheels with a live axle straight from toughbox nano gearboxes, using a rigid coupling from McMaster.

when running the motors, vibration in the motors and gearboxes is evident, beyond what is normal for a CIM motor to vibrate in a standard chain drive.

This is our first year running live axles, so we have no experience with acceptable vibration levels (if any).

Is it normal for a live axle setup to have some vibrations in it? or should it be just as rock solid as a standard setup?

I’m mostly concerned about fatigue in the aluminum chassis surrounding the drive system, and excessive wear on the gears since the load on them is varying and repetetive.

Your comments are very much appreciated.


A sketch or a picture of your set-up would help.

If you are coupling the nano output shaft rigidly to a live axle, and if the shaft and the axle are supported by two bearings each, then your problem may stem from misalignment (parallel, angular, or both) of the four bearings.

We are using brand new toughbox nanos on our drive train this year, and just recently started trying to drive. We noticed a clicking, and vibration coming from one of the toughbox nano gearboxes. Upon inspection discovered the large gear that meshes with the cim motor drive gear was malformed, one of the teeth was wider than the rest causing binding, and noise, about 30 seconds of running the jag fails and blinks red. We replaced that gear with one from an old toughbox and it works perfectly now.

Take your transmission off and try to turn the wheel by hand, if the resistance is variable (gets very hard or stops entirely at one point) then you probably have a similar issue.

I have seen several posts with similar problems, I am going to try to reply to all of them.