ZTR service interval w/ Amsoil AHF

[asker123]

I have a Cub Cadet Zero turn prosumer grade mower Z force SX54 with two Hydro Gear ZT3100 hydrostatic transmissions that turns the rear wheels.
Manual says dump the oil after first 75 to 100 hours then every 400 hours.

I did the first drain at 90 hours and I selected Amsoil hydrostatic transmission fluid 20W50 which claims that it is specifically designed for such Hydros. OEM manual says you can use any motor oil 20W50. I have mowed 15 hours since change and its all good.

My question is more on service interval. Amsoil says you can increase service intervals by 2x OEM recommendation which is every 400 hours now onwards with no mention of time based interval.

Can one really go 800 hours with this oil? I dont mind changing oil because of price but the complexity just makes me nervous. My mower has very strange placement of this HydroGear and changing oil is PITA. In any case I will forget the process as it will take me 12 years to get to recommended 400 hours and by that time mower's other items might give issues but just because I am a BITOG fan, I wanted to check how credible is the claimed 2x interval and how much it can be trusted.


https://www.amsoil.ca/p/amsoil-20w-...tBg0hOAwfYcc4evbg9x1YiF2WlaLGyTO1sGPIJGsv_Jt0

 

[FowVay]

Those drive systems are very expensive to replace. Oil changes every few years are not cost prohibitive and the time required to accumulate 800 hours of use could be excessive. Hydro-Gear chose a common motor oil for the fluid and gave a reasonable drain interval that I would stick with.

Oddly enough, Amsoil states that their hydrostatic gear oil is a high zinc formula but they don't list any form of zinc on their safety data sheet. OSHA requires that any form of zinc be listed if the content is greater than 1% so this would stir my curiosity. Even John Deere's J20C lists the ZDDP in their hydraulic fluids at 1.5%.

I'd have no issues with the Amsoil 20W-50 hydrostat fluid but I'd stick with what Hydro-Gear recommends for a drain interval.

To clarify, my knowledges of this subject is limited to what Tuff-Torq and John Deere have published for their drive systems. I have no knowledge nor have I ever owned a Hydro-Gear system.

 

[Brian123]

I have a Cub Cadet Zero turn prosumer grade mower Z force SX54 with two Hydro Gear ZT3100 hydrostatic transmissions that turns the rear wheels.
Manual says dump the oil after first 75 to 100 hours then every 400 hours.

I did the first drain at 90 hours and I selected Amsoil hydrostatic transmission fluid 20W50 which claims that it is specifically designed for such Hydros. OEM manual says you can use any motor oil 20W50. I have mowed 15 hours since change and its all good.

My question is more on service interval. Amsoil says you can increase service intervals by 2x OEM recommendation which is every 400 hours now onwards with no mention of time based interval.

Can one really go 800 hours with this oil? I dont mind changing oil because of price but the complexity just makes me nervous. My mower has very strange placement of this HydroGear and changing oil is PITA. In any case I will forget the process as it will take me 12 years to get to recommended 400 hours and by that time mower's other items might give issues but just because I am a BITOG fan, I wanted to check how credible is the claimed 2x interval and how much it can be trusted.


https://www.amsoil.ca/p/amsoil-20w-...tBg0hOAwfYcc4evbg9x1YiF2WlaLGyTO1sGPIJGsv_Jt0

Stick with the 400 Hour Recommendation!
Here is what will really help you out, blow the machine after each use, blow all around the transmission area.

My Dad had an MTD Riding Mower that lasted 600 hours and a Cub Cadet with the Kohler Courage that lasted 954 hours, I never changed the trans fluid, but I did blow the machine after each use. After 700 hours the Cub Cadet started whining, but my dad did not want to change the fluid. You are doing great buy using the Amsoil Hydrostatic Transmission Fluid, you can always do a UOA at 400 Hours if you want to go to 800 hours, it is probably cheaper to just change the fluid at 400 hours. JMO

 

[loneryder]

Those same Hydrogears are a real pain to change on my Ferris. I used that same fluid last change because I didn't want to do it again for a long time. No dirt gets in there so once you get the break in oil out it should last a long time.

 

[asker123]

Those same Hydrogears are a real pain to change on my Ferris. I used that same fluid last change because I didn't want to do it again for a long time. No dirt gets in there so once you get the break in oil out it should last a long time.

That is right. Mine doesn't even have an expansion reservoir and both hydros are independent and pretty sealed. I think these are internal expansion mechanism.
Considering this there is not much chance to get dirt in there. Others right fully suggested that blowing the air can remove debris from top that helps in cooling.
Changing oil is really difficult as these hydros are so hidden and access to fill port is complex.

Not just Amsoil but other manufacturers like JD's oil and some other tractor/mower manufacturer's brand oils also claim to have 2x OEM recommended oil change interval.

I think OEM's interval recommendation is based on 20W50 Dino oil.

 

[Brian123]

Not just Amsoil but other manufacturers like JD's oil and some other tractor/mower manufacturer's brand oils also claim to have 2x OEM recommended oil change interval.

Realize that Claims made without evidence can be dismissed without evidence!

 

[#18FAN]

Been on Amsoil a few years just ordered and will be trying HPL Tractor Life Synthetic 20w50 hydrostatic fluid this time never an issue with Amsoil just trying different fluid.

 

[edhackett]

That is right. Mine doesn't even have an expansion reservoir and both hydros are independent and pretty sealed. I think these are internal expansion mechanism.

Changing oil is really difficult as these hydros are so hidden and access to fill port is complex.

Hydro-Gear makes a fitting to make changing the oil easier. Pump oil in the small fitting and it overflows through the larger fitting, eliminating having to remove the fill port. Part #55752. It's included with the Hydro-Gear service kits or available separately from eBay or a multitude of online OPE vendors.

Ed

 

[brillo54]

Those same Hydrogears are a real pain to change on my Ferris.

I have a Ferris also and I changed fluid last fall. I started doing the change with the wheels on the machine. It was a pain. I remembered that I had seen a video where it recommended jacking it up and removing the wheels (you need the machines rear wheels in the air to purge the air out of the system anyway). Taking the wheels off made a world of difference. With the wheels off you can see what you are doing and don't have to be a contortionist. Try it if you haven't already.

 

[loneryder]

I have a Ferris also and I changed fluid last fall. I started doing the change with the wheels on the machine. It was a pain. I remembered that I had seen a video where it recommended jacking it up and removing the wheels (you need the machines rear wheels in the air to purge the air out of the system anyway). Taking the wheels off made a world of difference. With the wheels off you can see what you are doing and don't have to be a contortionist. Try it if you haven't already.

Yeah the first time I didn’t remove the wheels and it was awful. This last time I removed the wheels and it was much easier to reach the fill hole. It also takes a while to purge the air.

 

[loneryder]

Hydro-Gear makes a fitting to make changing the oil easier. Pump oil in the small fitting and it overflows through the larger fitting, eliminating having to remove the fill port. Part #55752. It's included with the Hydro-Gear service kits or available separately from eBay or a multitude of online OPE vendors.

Ed
View attachment 280977

Where do you screw this into? Fill cap?

 

[oilboy123]

I bought a new gear lube pump that just so happened to fit the drain hole threads on my K66 Tuff Torq. So I pumped from the bottom on both chambers. It worked well. But it started to leak out the drain of the other chamber. Which it says in the fill directions the chambers are not connected?

I just installed the drain plug on the other chamber and continued to fill. Then went and filled the other side. I did a lot of outboard lower units the same way at my job. So that is where I got the eureka moment. It is a lot easier than fighting the air trying to come to the top as you fill.

If I did not discover the gear lube pump that fit my trans, I would be all over that fill fitting.

 

[edhackett]

Where do you screw this into? Fill cap?

Top port. Video at 2:37 shows use of the fitting.

Ed

 

[loneryder]

Top port. Video at 2:37 shows use of the fitting.

Ed

That is hard to reach too. With the wheels off I could reach the top fill cap.

 

[#18FAN]

SCAG makes it easy pull top side port fill with 2.5 qts per side approximately top off expansion tank purge unit good to go.
Out Amsoil hydo no problems in HPL.

 

[johnD2]

Napa conventional 20w50 is on sale for $3.49 per quart. I put M1 15w50 in my 3600 Hydro gears last year...I swear they felt better with the factory fill of 20w50 conventional. And I know I bled them correctly after the oil change.

https://www.hydro-gear.com/wp-content/uploads/2023/03/BLN-0108_3400_3600_3800.pdf

 

[nascarnation]

I would think a lot of the life influence is due to operating temp. On my JD garden tractor, the hydro oil never got above 160F even in 90 degree ambients, so that oil was not oxidizing. I got a new Ferris with ZT2800s but it hasn't been hot enough yet to bother with a temp reading.

 

[asker123]

Thanks everyone for response. I would just go 1.5 times rather than twice of the OEM recommended interval which will 600 hour and approx 18 years for my usage.
I think Mower will have different issue to deal with by that time.
But I liked the idea of the Part #55752. Wish I knew this when I changed my oil last year. I had to jack the mower up, take the tire off to open the top fill port, then put the tire back, put mower down then fill the oil then close the side plug and then jack again to take the tire off to finally close that difficult to reach top fill port. Sigh !