# thrumming while pto engaged



## daniel2229 (Jun 5, 2011)

I always mow with muffs on, and from "day one" have always heard a thrumming while the Cub Cadet LTX 1040 pto is engaged. I noticed the other day while running the mower without the earmuffs, that I did not hear that noise. I put the muffs on, and I can hear it.

Is this just belt slap that I am hearing?

Thanks,

Daniel


----------



## dsterl (Jul 31, 2011)

I hear it also on PGT9500 I believe it coming from the blades. Gets worse if I slow the blades down! Just some kind of frequency noise.


----------



## phogbound (Jan 16, 2012)

Does it sound like rap music? Maybe you just need to tune your muffs to a different radio station.


----------



## Pipertec (Jan 12, 2012)

The sound you are hearing are "Harmonic Vibrations" You can hear them only in the ear muffs because you are hearing the lower frequency waves of the sound through your body and not through your ears. When you take your muffs off, the higher frequency sound waves which are transmitted through the air drown out the much softer lower frequency sound waves. I would suspect that the slight imbalance of your blades set up this vibration in the deck. Since you can never balance them perfectly, you get this low frequency vibration. It is amplified through the mower frame and into your body, thus when you put the muff on....that is all you hear.


----------

