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Rick, Factory Authorized Trainer
Category: Small Engine
Satisfied Customers: 8057
Experience:  Outdoor Power Equipment technical trainer since 1990, covering eight states.
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I have a cubcadet rzt 50, I think its a 2005, the transmissions

Resolved Question:

I have a cubcadet rzt 50, I think its a 2005, the transmissions are starting to slip, the left one worse than the right. I checked the belt and its not slipping. Is there a repair kit or overhaul kit to rebuild the hydrostatic pumps or motors ?
Submitted: 6 years ago.
Category: Small Engine
Expert:  Rick replied 6 years ago.

Hello, and thank you for choosing JustAnswer. I'll be assisting you today and am committed to providing clear and concise answers to your question.


There is not a kit as such, but all the internal component pieces are available as repair parts. If you can give me your complete model and serial (not the RZT50 on the side, but the numbers from the model plate), I can provide a parts list for you.

Customer: replied 6 years ago.
model # XXXXX the seat is 183649 , another model # XXXXX found is 17aa5a7p712, the sereal # XXXXX XXXXX . my cubcadet parts manual the transmission numbers are 618-04163A for RH, and 618-04164A for LH.
Expert:  Rick replied 6 years ago.
Give me a few moments to reference this, please.
Customer: replied 6 years ago.
also would like to know if there is a simpler fix than a rebuild.
Expert:  Rick replied 6 years ago.

Here's the parts list. You'll find all the internal components listed on pages 12-15.


However, before you do any repairs, since you've already checked the belt, be sure to go through the purging process to eliminate the possibility of air in the system causing the power loss. Here's the procedure for that.


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

The resulting symptoms in hydrostatic systems
may be:

1. Noisy operation.

2. Lack of power or drive after short term op-

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 11,
Figure 4.



The following procedures should be performed
with the vehicle drive wheels off the ground,
then repeated under normal operating condi-

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. With the bypass valve closed and the engine
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.


Let me know and we'll continue...

Customer: replied 6 years ago.
I have the parts manual with the parts list, but just in case the purge does not work which parts do I need to replace in the transmission pump?
Expert:  Rick replied 6 years ago.

That bad ones. And that's not intended as a flippant answer, it's accurate. There's no way to know for sure until you tear it down (if it's even necessary after the purge).


The most common things are wear in the cylinder and pistons on either the pump or the motor side, and also malfunctioning poppet valves. Once you take it apart, if necessary, then do a visual inspection of the components looking for signs of damage or wear. You'll be able to see it and feel it if you run your thumbnail across any of the rotating surfaces. Any parts that are damaged should be replaced. And of course all the seals should be replaced any time they are disturbed.


The case inside is pretty straightforward and easy. The hard part is getting the wheel hubs off. They are put on extremely tight so be sure and remove them before taking the transmission off the vehicle. Once it's off, those wheel hubs are almost impossible to get loose.


I'll post a manual for you that may be helpful.


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