Is this correct?

how does oil move around the system? I mean, I could see metallic shavings in the oil I took out, how does that get thru the pump? I'd have to think people are being pretty careless changing fluids to have something that big or abrasive get in there. Like metals are going to be more abrasive than some dust I would think.

Many of the dust particles floating around and which may also be adhered to mower surfaces are harder than steel (i.e. Quartz and Feldspar). And again, because of the close tolerances of the pump surfaces it doesn't have to be very large to cause an issue. The metal particles you may have seen in the oil/filter are tiny and able to pass through, but are of the same hardness so will not abrade the same way.

You guys can do whatever you want with your hydros, but I take what I feel is the safe route and leave mine be after an initial fluid and filter change. I have approximately 2000 hours on the hydros on both of my Exmarks with 1 fluid and filter change on each and they're both still quiet and function perfectly.

I'm no expert, I'm just following the advice of 5 head mechanics at mower shops that I've dealt with over the last 2 decades as a professional landscaper and it's worked for me.

I don't know what the correct action is. I've only ever had one mower with hydrogear transmissions, and I did do the initial change, only to get a bigger mower. So I won't ever know how they wear or last. My new mower I want to last a long, long time. But I don't know that I'll ever see 2000 hours on this one, I'll be almost 90 at the rate I cut grass. But at the end of this season I'll be faced with, do the initial change, or just leave it. I'm gathering all the info I can.

DK35vince said:

I'm with this post then.
If the filters don't help, what's the point of the filter.

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The filter stops repeat performances
Thus a piece of crud that damages the valve chest or valve plate hopefully will only do it once and wear particles will be removed before they clog valves .
Th problem is very few will take the time to clean the tranny properly before replacing the filter and filler cap .
I degrease, soda blast then pressure wash before I touch either cap or filter.
Yet there are 10,000 U-toob idiots showing you how to fill using funnels & tubes.
When you regularly pull out trannies you will understand just how much sand & other gritty debris ends up all around the transmission.
So unless it has a remote headder tank it comes out for cleaning before the oil gets changed.
Transmission oil filters are generally a lot finer than engine filters and if you are filtering down to 4 microns then dirt in there is a big problem.
When I have to pull one apart it gets done in the workshop shower cubicle after the walls are wetted down & when not being worked on is covered with a damp cloth.
Again you will see 5000 U-Tube fixes with the box sitting on a filthy floor or bench in a filthy shop with wide open doors allowing dirt & dust to drift in on the breeze.
And then you see the finished tranny working fine.
What you don't see is it fail in 1 or 2 seasons time dust to all the crud that was introduced during the pull down

I changed my hydro fluid and filters at 100 hours. The factory juice coming out looked perfectly good, light straw colored, not a speck of glitter or grey in it. It could have gone quite a bit longer.

EricC said:

I don't know what the correct action is. I've only ever had one mower with hydrogear transmissions, and I did do the initial change, only to get a bigger mower. So I won't ever know how they wear or last. My new mower I want to last a long, long time. But I don't know that I'll ever see 2000 hours on this one, I'll be almost 90 at the rate I cut grass. But at the end of this season I'll be faced with, do the initial change, or just leave it. I'm gathering all the info I can.

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So long as the hyrdos are still in warranty do whatever the manual says to do, save receipts, and while servicing take every measure possible to ensure that contamination does not get into the system. I only say this because should you have a warranty claim against Hydro-Gear during the warranty period, you are more likely to have a positive experience had you followed the manufacturer's recommendations as opposed to ignoring them. After the warranty period you can take whatever risk you want should you be confident that either leaving it or servicing it each year will cause you no problems.

I am of the mindset that if I follow the manufacturer's recommendations (in both servicing and operation) I should have the best possible experience from the equipment.

cruzenmike said:

So long as the hyrdos are still in warranty do whatever the manual says to do, save receipts, and while servicing take every measure possible to ensure that contamination does not get into the system. I only say this because should you have a warranty claim against Hydro-Gear during the warranty period, you are more likely to have a positive experience had you followed the manufacturer's recommendations as opposed to ignoring them. After the warranty period you can take whatever risk you want should you be confident that either leaving it or servicing it each year will cause you no problems.

I am of the mindset that if I follow the manufacturer's recommendations (in both servicing and operation) I should have the best possible experience from the equipment.

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That's where i'm leaning as well.

Straight out of the Hustler manual.....

"Initial system oil and filter change MUST be done after the first 75 hours of use or one year, whichever comes first. Thereafter, replace filter and oil in each transmission every two years or 200 hours, whichever comes first."

I changed mine at about 30 hours(1 year) and have about 120 more hours now 4 years later. I will change mine again, but I will likely wait a year or two more. Just not putting the hours others are on the transmissions.