@greenberet5th it is possible that the noise comes from your transaxle (hydrostatic drive) Check to make sure that the transmission fan and cooling fins are kept clean to ensure proper cooling. Do not attempt to clean fan or transmission while engine is running or while the transmission is hot. To prevent possible damage to seals, do not use high pressure water or steam to clean transaxle.
inspect cooling fan to be sure fan blades are intact and clean.
Inspect cooling fins for dirt, grass clippings and other materials. To prevent damage to seals, do not use compressed air or high pressure sprayer to clean cooling fins.
It is possible that you may require oil etc. in the transaxle. for that we would need to know which model transaxle your mower has. (They use a few different kinds)
Try to purge the transmission:
PURGE TRANSMiSSiON
_CAUTION: Never engage or disengage freewheel lever while the engine is running. To ensure proper operation and performance, it is recommended that the transmission be purged before operating tractor for the first time. This procedure will remove any trapped air inside the transmission which may have developed during shipping of your tractor.
IMPORTANT: Should your transmission require removal for service or replacement, it should be purged after reinstallation before operating the tractor.
1. Place tractor safely on a level surface - that is clear of objects and open - with engine off and parking brake set.
2. Disengage transmission by placing freewheel control in disengaged position (See "TO TRANSPORT" in this section of manual).
3. Sitting in the tractor seat, start engine. After the engine is running, move throttle control to slow position. With motion control lever in neutral position, slowly disengage clutch/brake pedal.
CAUTION: At any time, during step 4, there may be movement of the drive wheels.
4. Move motion control lever to full forward position and hold for five (5) seconds. Move lever to full reverse position and hold for five (5) seconds. Repeat this procedure three (3) times.
5. Move motion control lever to neutral position. Shutoff engine and set parking brake.
6. Engage transmission by placing freewheel control in engaged position (See "TO TRANSPORT" in this section of manual).
7. Sitting in the tractor seat, start engine. After the engine is running, move throttle control to half (1/2) speed. With motion control lever in neutral position, slowly disengage clutch/brake pedal.
8. Slowly move motion control lever forward, after the tractor moves approximately five (5) feet, slowly move motion control lever to reverse position. After the tractor moves approximately five (5) feet return the motion control lever to the neutral position. Repeat this procedure with the motion control lever three (3) times.
Your transmission is now purged and ready for normal operation."
1 
1 
2.3k 