DescriptionThis video provides step-by-step repair instructions for replacing the transmission spring on a Troy-Bilt lawn mower (model 12AVB2RQ766). The most common reason for replacing this part is if the self-driving feature is not working properly.
All of the information for this replacement video is applicable to the following brands:
Troy-Bilt
Step-By-Step Instructions1
To replace the transmission spring on your Troy Built lawn mower, you will need a 9/16 inch socket, a 3/8 inch socket, and needle nose pliers.
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Before you begin the procedure, make sure the engine has cooled.
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We also recommend there be little or no fuel in the tank.
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For safety, detach the ignition coil wire from the spark plug to prevent the engine from accidentally starting.
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Now, tip the lawn mower back and use a weight to hold the handle assembly down.
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Using the 9/16 inch socket, unthread the nuts securing the two front wheels.
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Slide off the two drive gears along with the wheel guards.
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Now use the 3/8 inch socket to unthread the 7 lower screws securing the front transmission cover.
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Next, unthread the two upper screws securing the cover.
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Pull the wheel adjustment lever outwards so you can fully detach the cover.
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Remove the two drive shaft bearings.
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You can now slide the front axle assembly off.
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Use the needle nose pliers to depress the tab to release the spring insert from the transmission support.
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Dislodge the transmission assembly and depress the tab to release the insert and spring from the transmission.
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Slide the old spring off of the insert.
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Install the new transmission spring by sliding it onto the insert.
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Keeping the insert stopper facing downward, snap the insert into place in the transmission.
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Fully position the transmission and snap the opposite end of the insert into the support.
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Align the front axle assembly on the transmission support.
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Slide the two drive shaft bearings onto the axle and fully insert them into the axle plates.
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Make sure the bearings are positioned in the notches in the support.
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Hold the axle assembly in place as you reposition the front transmission cover by first inserting the tab under the belt slot in the deck.
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Make sure the drive cable is positioned in the notch in the cover.
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Pull the wheel adjustment lever outward to properly align the front of the cover.
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Replace the nine screws to secure the cover, starting with the lower middle screw.
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Reposition the wheel guards followed by the two drive gears.
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Align the two front wheels and thread the nuts to secure them.
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Remove the weight and return the lawn mower to its upright position.
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Reattach the ignition coil wire to the spark plug.
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Refill the fuel tank if necessary and your lawn mower should be ready for use.