ZD326 hst noise?

[Long Gone]

I purchased a used zd326, 2013 model with 100 hours, last week... from a reputable kubota dealer and salesman that I have used often.
Used the mower for the first time, about 30 or 45 minutes mowing moderately thick grass, and noticed that the steering controls began to feel "grabby" instead of smooth, and that the HSTs seemed more noisy- not the usual hst "whoosh" but more of a raspy rattly harsh buzz instead.
Is this normal for the zero turns?
Drove the machine around the yard a few minutes today, noticed the same thing once it got warm.
HST fluid level is full, machine was serviced about 20 hours ago. I found nothing out of sort on visual inspection of linkages and the HSTs.
I'm open to any thoughts on this. Zero turns are new to me. I'm not enjoying the steering much- it seens darty, I miss my b series and MMM. Am hoping this gets better soon.

Thanks in advance,
LongGone

 

[1970cs]

I would ask your salesman if they have another ZD326 new on the lot so you can compare operations. I would also hurry because the ZD326 is discontinued and replaced by ZD1211.

Pat

 

[rjcorazza]

Some thoughts...
My zd326 was driving differently last month, mostly sluggish movements when cold and harsh when warm. It was overdue for transmission fluid and filters anyway, so I changed it and it smoothed out.
Other considerations would be confirming the hst cooler fan is working, and that the oil cooler is not clogged up with grass.

 

[Grandad4]

Don't know much about ztr's, but a noisy HST just after servicing would make me wonder who did the service and what fluid was used. Can the dealer vouch for how it was serviced? So many stories of erratic, noisy HST operation due to using cheap hydraulic fluids.

 

[man00]

Sounds like it may have air in the system,
you are mowing at full throttle