John Deere won't move forward or reverse?
The engine starts and runs fine, but the mower will not go anywhere in either direction. This page runs the checks in the order that finds the cause fastest: the bypass rod, the drive belt, trapped air, and only then the transaxle itself.
Quick answer: if the mower was recently pushed, towed, or trailered, check the bypass rod at the rear first - left out, it disconnects the drive completely. After that, confirm the drive belt is intact and seated, then purge air from the hydrostatic unit. If all of that checks out, the problem is in the transaxle.
Different symptom, different page: if the mower still drives but loses pulling power on hills once it warms up, that is hydrostatic heat fade, not a no-drive failure. See John Deere won't climb hills for that diagnosis.
First checks, in order
These are ordered by how often they turn out to be the answer and how little they cost to check. Do them before assuming the transmission is dead.
- Confirm the bypass rod (freewheel rod) at the rear of the tractor is pushed back into the drive position.
- Look at the drive belt from the engine to the transaxle input pulley. A broken or thrown belt means the engine runs but nothing turns.
- Check that the belt is seated on every pulley and the idler is holding real tension against it.
- Test at full throttle. Hydrostatic units need engine speed to build drive; a fast idle test can fool you.
- Check the wheel hub keys. A sheared key lets the axle turn while the wheel does nothing.
- On serviceable units, check the oil level in the transaxle reservoir.
- Make sure the parking brake is fully released and the pedal or lever linkage actually moves the arm on the transaxle.
Likely causes
A no-drive mower with a healthy engine comes down to a short list. The good news is the cheap causes are also the common ones.
Most common after moving the machine: the bypass rod
The rod at the back of the tractor that lets you roll it by hand also disconnects the drive. If it was pulled out to push the mower into the garage or onto a trailer and never pushed back in, the engine runs and nothing moves. It takes two seconds to check and it embarrasses everyone at least once.
Broken or thrown drive belt
The drive belt carries power from the engine down to the transaxle input pulley. If it snaps, shreds, or jumps off, you get a healthy engine and zero motion in either direction. This is a different belt than the deck belt that spins the blades.
Air in the hydrostatic circuit
After the unit has been tipped, transported, run out of oil, or serviced, trapped air can keep the hydrostatic pump from building drive pressure. The cure is the purge procedure below, which the transaxle maker publishes for exactly this symptom.
Trouble inside the transaxle
If the externals all check out, the problem is in the unit itself: damaged bypass valve parts (valve, spring, pin, or washer), or plain internal wear. A unit that moves when cold and quits when hot is telling you about wear, not air.
The purge procedure (air in the hydrostatic unit)
Tuff Torq, who builds the K46 transaxle used in many of these tractors, publishes an air-purge procedure for a unit that will not drive after transport, tipping, or oil service. This is the condensed version.
Safety first: this procedure runs the engine with the drive wheels off the ground. Use jack stands rated for the machine, chock the front wheels, keep hands and clothing away from the spinning wheels, and follow your operator's manual. If any of that is not comfortable, have a shop do it.
Check the oil level first (on units with a serviceable reservoir). Low oil makes purging pointless and can be the whole problem.
Raise the rear of the tractor so the drive wheels are off the ground, supported on jack stands rated for the machine. Chock the front wheels.
Start the engine and let it run at low idle.
Hold the forward pedal down and open and close the bypass valve a few times. Do the same holding reverse. Each cycle only takes a couple of seconds.
With the bypass back in the run position, work the forward and reverse pedals back and forth. Repeat until the axles start to turn.
Once the wheels respond, bring the engine speed up and keep cycling forward and reverse until the transaxle responds fully in both directions.
Shut the engine off, lower the tractor, and test drive on flat ground.
When it is the transaxle
If the bypass rod is engaged, the belt is good, the hub keys are intact, the linkage moves the arm, and purging changed nothing, the transaxle itself is the remaining suspect. Tuff Torq's own guidance for that case is blunt: once the externals and oil level check out, the unit gets rebuilt with a repair kit or replaced.
Which way it points:
- Never moves at all, even cold: bypass valve parts or a mechanical failure inside the unit.
- Moves when cold, quits when hot: internal wear and heat fade - the hill-climbing guide covers that path, including fluid service, K46 replacement, and the K66 upgrade.
- One direction only, with good linkage: usually internal as well.
- John Deere won't climb hills - the heat-fade diagnosis, for a mower that still drives but gets weak under load.
- John Deere hill-climbing owner reports - the year-by-year report archive behind the hydrostatic story.
- John Deere L130 belt diagram - deck belt routing, and the difference between the deck belt and the drive belt.
The checks and purge steps on this page follow Tuff Torq's published service guidance for its hydrostatic transaxles, organized into the order that finds cheap causes first. Models and linkages vary by year - verify against the operator's manual for your machine, and treat any procedure that raises the tractor or runs it on stands with real caution.
FAQ
I pushed or towed the mower, and now it will not drive. What happened?
Almost always the bypass rod. Pulling it out lets the mower free-wheel, and it does not drive again until the rod is pushed back in. If the rod will not stay engaged or drive never comes back, the bypass valve, spring, pin, or washer inside can be damaged, and that is a repair rather than a reset.
Does purging actually fix a mower that will not move?
It fixes the specific case of air in the hydrostatic circuit, which is common right after transport, tipping, an oil change, or running the unit low. Tuff Torq publishes the purge procedure for this exact symptom. Purging does not bring back a unit that is worn out inside.
It moves in one direction but not the other. Same checks?
Start with the pedal or lever linkage, since a misadjusted linkage can rob one direction. The bypass rod and drive belt are not direction-specific, so if the linkage checks out, a one-direction failure usually points inside the transaxle.
Is this the deck belt or the drive belt?
The drive belt. The deck belt only spins the blades; the mower drives fine without it. If the blades work but the mower will not move, you are looking at the drive side: bypass rod, drive belt, or transaxle.
It moves fine cold, then stops driving once it warms up. Is that this problem?
That heat pattern is its own problem: hydrostatic fade from internal wear, which usually shows up on hills first. The hill-climbing guide on this site covers that diagnosis and the repair paths for it.
What oil goes in the K46?
Tuff Torq recommends its own hydrostatic drive fluid, with a published fluid chart for each unit. Many of these transaxles were sold as sealed with no scheduled service, but Tuff Torq publishes an oil replacement procedure, so they can be serviced.