Hydro-Gear EZT transmission in most low end ZTRs

[txdon]

Has anyone tried to check/add/change the fluid in a Hydro-Gear transmission on a low end ZTR? The less you pay for a ZTR the harder it is. On mine (Craftsman) the transmission is sealed with an non-assesable fill port. I cannot check the level.

After I mowed for an hour the left side turning got sluggish when I was going up an incline and it did not recover very quickly. The next day when I mowed there was no problem, but it has happened twice at the same spot in the yard on different days. If I just start out and mow on the incline when the mower is cool there is not a problem. I figure it is either a fluid problem or a belt problem but when I tried to check the fluid I realized I would have to remove the transmission from the mower or drill an access hole in the platform by the engine.

My plan is to first buy a new belt and if the problem reoccurs then drill an access hole. The transmission is a Hydro-Gear EZT ZC. (150 hours, out of warranty 6 years old)

Has anyone had any problem with their non-assessable transmission and how was it resolved?

 

[sld]

txdon, I have a Toro with the same transmission type and have always wondered about the same thing. So far, I have had no problems but I dug up this old bookmark I found some time ago. See what you think. If I ever have any issues I would not be afraid to do the tear down.

If you end up changing fluid like the guy in the link please post back the results. I'm sure some day I will be doing it too.

Toro Timecutter Z5000 - Need help with Hydrostatic Tranny - Tractors Forum - GardenWeb

 

[txdon]

Sid, thanks for the link. One new transmission is more than the mower is worth so if the sloppy steering starts and continues I will try the fluid replacement before I sell it for parts. It says the transmission must be removed and turned upside down, but I think I will first try to drill a hole through the tractor directly over the fill port and suck the oil out. There is a lot of linkage that will be a pain to reconnect if I have to remove it. Yesterday it was all good for a quick 30 minute mow. I did notice the drive belt tension pulley is maxed out so possibly there may have been some belt slippage - I hope.

 

[Bird]

My little Toro's 3 year warranty expired in March, but I've only got 97.3 hours on it. So far no problem.

 

[txdon]

http://www.google.com/url?sa=t&rct=...hgFpXAE4U6iIK_latIJknbQ&bvm=bv.70138588,d.b2U

Here is a PDF file of the manual for the Hydro-Gear transmission EZT ZC and ZD

(A replacement Hydro-Gear transmission is $1,720.00 - $860.00 each side from Sears Parts)

From the above link:

The fill port diagram is shown on page four.

FLUID CHANGE PROCEDURE
This transaxle is factory filled, sealed and does not require oil maintenance. However, in the event of oil contamination or degradation, oil addition or change may alleviate certain per- formance problems.
1. Remove the transaxle from the vehicle.
NOTE: If removing the wheel from the transaxle, do so by removing the four (4) lug nuts. Do not remove the axle/hub nut.
2. Clean the oil fill port area of any debris. 3. Remove the oil fill port fitting.
FLUID CHANGE
4. Position the transaxle so the oil will drain completely out of the housing.
5. Fill the transaxle at the oil fill port according to Figure 4.
6. Install the oil fill port fitting.
7. Purging will be required. Refer to the purging procedures on Page 10.
8. Recheck the fluid level once the unit has been operated for approximately 1 min- ute.

20W50 engine oil
52.4 fl. oz. (1550 ml) to 55.8 fl. oz. (1650 ml)

The level of the oil should be between .75" and 1.5" from the top of the fill port.

PURGING PROCEDURES
Due to the effects air has on efficiency in hy- drostatic drive applications, it is critical that it is purged from the system.
These purge procedures should be imple- mented any time a hydrostatic system has been opened to facilitate maintenance or any additional oil has been added to the system.
Air creates inefficiency because its compres- sion and expansion rate is higher than that of the oil approved for use in hydrostatic drive systems.
The resulting symptoms in hydrostatic systems may be:
1. Noisyoperation.
2. Lack of power or drive after short term op- eration.
3. High operation temperature and excessive expansion of oil.
Before starting, make sure the transaxle/trans- mission is at the proper oil level. If it is not, fill to the specifications outlined on Page 9, Figure 4.
The following procedures should be performed with the vehicle drive wheels off the ground, then repeated under normal operating condi- tions.
1.With the bypass valve open and the engine running, slowly move the directional control in both forward and reverse directions (5 or 6 times), as air is purged from the unit, the oil level will drop.
2.Withthebypassvalveclosedandtheengine running, slowly move the directional control in both forward and reverse directions (5 to 6 times). Check the oil level, and add oil as required after stopping the engine.
3.It may be necessary to repeat Steps 1 and 2 until all the air is completely purged from the system. When the transaxle moves for- ward and reverse at normal speed purging is complete.

I cut and pasted from the above link in case the link goes bad I can always refer back to this post.

 

[sld]

Great info! Thanks.

 

[txdon]

#8 says to check fluid after 1 minute of use - do they realize that the transmission must be again removed. Looks like a drilled hole will have to be done so a second removal will not be necessary. You would think they would have a access plug on the mower frame.

The one thing I have not found is how to remove the fill port. Is it an allen wrench, slotted, pop off or ??. . . . .Mine sits an inch under the frame and I cannot tell. It would make a difference on how big of a hole I would drill.

 

[sld]

I would think if you measured what you took out and replaced with the same amount you could skip this step.

Surely when the thing was built it had the correct amount of fluid put in it. Assuming there are no leaks though.

Start with a smaller hole that at least lets you see what you are dealing with. Harbor freight bore scope would be nice too.

 

[txdon]

The USB scope for about $20 would be the perfect exploratory tool, thanks.

 

[txdon]

I was at Sears today to get a belt and looked at the new Zs. They are still using Hydro-Gear transmissions but they NOW have a hole in the frame on the side of the motor to access the fill port. Just looking at it I could not tell if it was an alan or star set screw recessed on top of the port.

I'll let you know if the belt solved the problem, it's dry here now so it might be a while.