Warning: While Tuff Torq do recommend changing the oil in its unit, some other tractor manufacturer provide a "sealed unit" and don’t need to replace the oil in the transaxle.
Be advised that if you’re doing the oil change it is on your own responsibility.
Here’s the procedure for changing the oil on a Tuff Torq K46 transaxle.
Note: Make sure to use appropriate jack and support when jacking the tractor.
1. Removing the transaxle form the tractor.
Raise rear wheels off the ground, support the rear of the tractor with jack stands.
You'll have to remove the drive belt by releasing the tension on the idler pulley, disconnect all the linkage, brake, forward/reverse and the freewheeling rod from the transaxle, and finally unscrew the 4 bolt holding the transaxle on the frame.
2. Remove the fan pulley combo (snap ring).
3. Removing the fill cap.
To remove the fill cap, you’ll have to use a sharp knife (box cutter) be gentle, you’ll have to reuse the cap if it’s not damage
4. Take off the magnet under the fill cap (you can see the dirt from the run-down steel)
Note: For a perfect job, you have to remove the lower casing and clean the other magnets. You’ll find two magnets near the final drive and two others near the oil inlet of the hydraulic pump parts #8 in the diagram below.
: If the transaxle is still under warranty I do not recommend to open it. You’ll be voiding the warranty by doing that.
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Here you can see the two orifices that fill both side of the transaxle, gears side and pump side.
5. Draining the transaxle
To drain the transaxle, you’ll have to turn it upside down.
Note: Make sure to use an adequate size container to prevent spilling oil.
It could take few hours to completely drain the transaxle.
It is recommend by Tuff Torq to use 5W50 full synthetic oil. The transaxle requires 1.85 Liter to fill it. You'll need to buy two liters. You can use the brand of your choice.
6. Fill up the transaxle.
Take a appropriate size funnel and pour the oil slowly in. Remember the transaxle doesn’t take the full two liters, so after 1 liter and a half it could take a bit of time to fully fill it.
Note: Make sure to respect the oil fill up mark show on the next picture.
7. The bleeding procedure
Here you have two possible choices. You can bleed the transaxle on a stand using a power drill to run the pump, which gives you the opportunity to check the oil level after the bleeding procedure. Otherwise, reinstall the transaxle on the tractor by following the steps above in reverse order.
Note: If you decide to reinstall the transaxle on the tractor you’ll lose the ability to check the oil level after the bleeding procedure, but if the fill up was followed correctly you should obtain the same result.
A. Start and run engine at SLOW idle.
B. While alternately depressing the forward and reverse pedals, engage and disengage the release wheel lever (freewheeling rod).
C. Continue this procedure until the rear wheels start to rotate. This step may take up to 10 minutes to perform.
D. Lower the machine to the ground.
E. With control pedals in neutral, push the machine forward and then rearward to turn the motor rotating group.
F. Start and run the engine at FAST idle.
G. Quickly depress and release the forward and reverse pedals until the machine moves without hesitation.
Note: Tuff Torq recommend changing the oil at 50 hours for the first time and then every 200 hours.
Originally posted on MyTractorForum.com November 2011.