Last Updated on October 5, 2026 by Umar Farooq
A washer transmission gearcase is the sealed gearbox under the basket of a top-load washer. It takes one rotation direction from the motor and produces two behaviours: the oscillating stroke that drives the agitator or wash plate, and the locked rotation that spins the basket. It also contains the shift mechanism that swaps between them, and a quantity of oil that is supposed to stay inside it forever. When that oil arrives on your floor, the diagnosis is finished — and so, usually, is the gearcase.
It is the single largest part on most top-loaders, and the honest version of this page has to say early that the repair is often not the right call. What follows is how to confirm it, how to tell it apart from a far cheaper part that produces the same symptoms, and which gearcase belongs to which machine if you decide to go ahead.
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Oil on the floor is the one symptom that settles it
Almost every washer fault needs a sequence of tests. This one does not.
Pull the machine out and look underneath with a torch. If you find a dark, slightly viscous film — not clear water, not soapy residue, but oil, usually under the centre of the cabinet and sometimes thrown outward in a rough circle by the spin — the diagnosis is complete. GE Appliances says so without hedging: “Oil leaks on the floor come from the washer transmission. There is no repair on the existing transmission; it must be replaced.”
Two parts of that sentence matter. The first is the certainty: no other component on a washing machine contains oil, so an oil leak has exactly one source. The second is the part people argue with — there is no repair. Gearcases are not serviceable in the field. They are not opened, resealed or topped up. Manufacturers supply them as sealed assemblies and that is the whole of the available repair.
There is a corollary worth acting on immediately. Once the oil is leaving, the gears are running on what is left, and the damage accelerates. A machine with a confirmed oil leak should not be run for another three weeks while you think about it. If you are going to replace the gearcase, do it now; if you are not, stop using it before it takes the tub seal and the basket with it.
Half a cycle works, which narrows it to the shifter
Without oil on the floor, the next most useful observation is which half of the cycle still works — and this is where a great many unnecessary gearcases get bought.
It agitates but will not spin. On a modern Whirlpool-group machine this is far more often the shift actuator than the gearcase. The actuator is a small motorised unit bolted to the outside of the gearcase whose only job is to move the mode shifter between agitate and spin. It fails on its own, it is a fraction of the size of the part it is bolted to, and the symptom is identical. Check it before anything. The other candidates for this symptom — a lid switch that never confirms, water still in the tub, a basket the balance system will not accept — are all covered on washing machine won’t spin and all of them are cheaper than a gearbox.
It spins but will not agitate. On an older direct-drive machine this is classically the agitator dogs: small plastic cams inside the agitator itself that wear round and let the top half freewheel. You can confirm it in two minutes by holding the agitator while the machine tries to agitate and feeling whether the shaft below it is moving. Top load washer not agitating runs the full sequence.
Neither works and the motor hums. Something is seized, and a seized gearcase is one candidate among several. Turn the basket by hand with the power off before concluding anything.
It makes a metallic grinding under load and the noise changes between wash and spin. This is the symptom with the best claim on the gearcase, particularly alongside any oil. Even here, check the obvious first — a coin between the basket and the tub produces an astonishingly convincing impression of a dying gearbox.
The clunk that is supposed to be there
Worth a short section on its own, because it sends people to parts listings every week.
A top-loader makes a distinct knock as it changes mode. Whirlpool documents it as normal: “The drive system will make a knocking or thumping noise as it shifts from agitation mode to spin mode or vice versa.” That is the shifter engaging, which is a mechanical event involving metal, and metal makes a noise. The same page attributes the other common knock to an off-balance load, where “the tub may hit the washer’s cabinet”, and gives the fix as loading evenly and levelling the machine with all four feet on the floor and the locking nuts tightened.
The distinction that matters: a single clunk at the moment the cycle changes mode is the design working. A repeating metallic noise during agitation or during spin, in rhythm with the drive, is not.
A washer transmission gearcase is the priciest part of a shrinking format
Some context that changes how you should think about the spend.
The mechanical gearcase exists because an agitator machine needs two different motions from one motor. Impeller and wash-plate machines, and every front-loader, do not — they vary the motor itself and dispense with the gearbox entirely. The industry has been moving that way for years, which is why the gearcase is a part category with a shrinking installed base, and why so many of the listings you will find are for machines built within the last few years or for platforms twenty years old, with less in between than you would expect.
Practically, that means two things. Availability for the older platforms is better than you would guess, because the parts were made in enormous numbers. And the gearcase on a current machine is a major assembly whose cost sits in a different bracket from a pump, a valve or a lid switch — on most top-loaders it is the most expensive single component you can buy for it. Our agitator vs impeller washer page covers what you actually gain and lose by moving between the two formats, which becomes a live question the moment this part fails.
Match the gearcase to the platform, not to the badge
The numbers here matter more than anywhere else in a washer, because a gearcase bolts to a specific basket drive, carries a specific shaft length and spline, and seals against a specific tub.
Find the model number on the serial plate. On a top-loader, lift the lid and look at the rim first, then the back panel. Photograph it.
Read the number cast or labelled on the gearcase itself. You will have to tip or dismantle to see it, which is annoying, and it is still the authoritative number. The supersession lists in this category are long: the W11454372 gear case replaces thirteen earlier numbers including W10469845, W10735106, W10795113 and W11393694, and the legacy 3360629 transmission names more than twenty, among them 285312, 3349296, W10155438 and WP8546456. Any of those on your old part puts you in the right family.
Check what is in the box. This is the detail that decides whether the job goes well. GE’s WH03X33729 assembly, for instance, is described as coming “with the tub seal and drive shaft” — and the tub seal is almost always the thing that let go in the first place, so a gearcase supplied without one means a second order and a stalled repair. Check before you buy, not after.
Ignore the badge. Whirlpool, Maytag, Amana, Crosley, Admiral, Inglis, Roper, Estate and Kenmore 110 machines share drive platforms freely. Kenmore is not a manufacturer: the 110 prefix is Whirlpool. A listing that names four brands is describing one gearbox, not four.
One honest caveat about the listings themselves. The WH03X33729 page carries a line worth repeating in full: it recommends that you “either refer to your appliance service manual, contact your appliance manufacturer, or contact a service professional to validate the needed part number for your appliance prior to purchasing”. That is the seller telling you the same thing this page is telling you, which is unusual and to their credit.
Four gearcases across three generations of top-loader
Whirlpool 3360629: the legacy neutral-drain transmission
The direct-drive era part, and the reason it is still stocked is that an enormous number of those machines are still running. Whirlpool’s listing names the superseded numbers in full — more than twenty of them, including 285312, 3349296, 3360630, W10155438, W10251783, WP62621 and WP8546456 — and names compatible machines including WET4027EW, WET4024EW, LTE5243DQ, WET3300XQ and WGT3300XQ.
Who it suits: an owner of a direct-drive Whirlpool, Kenmore 110, Roper or Estate machine, or one of the stacked laundry centres built on the same platform, whose old transmission carries any of those numbers.
What it does not do: it does not come with the coupler, and on this platform the coupler sits between the motor and the transmission and is the part that fails far more often. Confirm the coupler is not your fault before ordering this.
Whirlpool W11449840: the current-generation OEM gear case
Whirlpool’s own gear case for its recent top-load platform, described by the manufacturer as compatible with select Whirlpool, Kenmore, Maytag and Admiral washing machines. Four badges, one gearbox, exactly as above.
Who it suits: a reader who has confirmed W11449840 against their own machine and wants the manufacturer’s part with its warranty.
What it does not do: this is an OEM listing of the usual kind — exact about the number, silent about which models. It will not confirm fit for you. And if your symptom is “agitates but will not spin”, go and check the shift actuator before you spend this much, because on this platform that is the commoner fault by a distance.
Whirlpool W11393685: the sibling gear case with the supersession list
The other current Whirlpool gear case, and the listing is more forthcoming than most: it names W10447976, W10811956, W10868473, W11134159, W11393686 and W11455453 as the numbers it replaces, and states it applies to some Kenmore, Whirlpool, Crosley and Maytag machines.
Who it suits: anyone whose old gear case carries one of those six numbers. This is precisely the situation the supersession list exists for, and it is the fastest confirmation available on this page.
What it does not do: note that two very similar Whirlpool numbers — this one and the W11449840 above — are not interchangeable. The same brand, the same era, two different parts. If ever there were a demonstration that the badge decides nothing, this is it.
TechZupply WH03X33729: the GE assembly that includes the tub seal
GE’s gear case for the Hotpoint and GE top-load platform, described as a functional equivalent to the earlier WH38X24475 and WH38X27335. The listing sets out the job in the clearest wording of any product on this page: it “drives the impeller that agitates the clothes during the wash cycle. Rotates the spin basket in the spin portion of the cycle. Shifts the drive system between the agitation and spin modes.”
Who it suits: GE and Hotpoint owners whose old part carries WH03X33729, WH38X24475 or WH38X27335. The decisive detail is that it comes with the tub seal and drive shaft — if yours leaked, that is the part you would otherwise have to order separately and wait for.
What it does not do: it does not cover GE’s other transmission kit numbers, and the listing itself tells you to validate the part number against your service manual before buying. Take that advice.
When the arithmetic says buy a machine
This is the part a page that earns on the sale is supposed to leave out.
A gearcase is the most expensive part on the machine and it is one of the more involved jobs on it — the basket comes out, the shaft comes through the tub, and the tub seal has to be done at the same time. What you get in return is bounded. The US Department of Energy’s 2024 clothes washer rulemaking puts average washer lifetime at “13.4 years” and states that in the repair scenario, “the product’s life is extended by approximately 5 years”. Five years is the upside, not twenty.
So the decision has a shape. On a three- or four-year-old machine with no other symptoms, a gearcase is a reasonable repair and the machine has plenty of life in it. On a ten-year-old machine, you are buying the most expensive part on an appliance already past the midpoint of its expected life, and the same money has a much better home. And if the gearcase failure arrives alongside bearing noise or a leaking tub seal, that is not one repair, it is a rebuild. The washing machine repair cost page sets out the 50% rule and what to ask a technician before agreeing to anything.
The genuinely bad outcome is the middle one: paying a technician to fit a gearcase to an old machine and discovering the basket, the hub or the tub seal needed doing too. If you are having this done rather than doing it, get the quote itemised before anyone orders a part.
FAQ
How do I know for certain it is the transmission and not something cheaper?
Oil under the machine is conclusive, and GE states it plainly: oil on the floor comes from the transmission and there is no repair on it. Without oil, work through the cheaper parts that produce the same symptoms first — the shift actuator for no-spin, the agitator dogs for no-agitate, and a foreign object for grinding. The gearcase should be the last thing left standing, not the first thing suspected.
Can a washer transmission gearcase be repaired or refilled?
No. They are supplied as sealed assemblies and manufacturers do not publish a service procedure, a seal kit or a fill specification for them. GE’s wording is “there is no repair on the existing transmission; it must be replaced.” Anything you read about topping one up is somebody improvising with a part that spins a loaded basket.
What is the difference between a gearcase and a shift actuator?
The gearcase is the gearbox that produces the two motions. The actuator is a small motorised unit bolted to the outside of it that moves the shifter between them. They produce the same symptom when they fail and they are not remotely the same purchase, which is why the actuator gets checked first on any machine that agitates but will not spin.
Is it normal for my top-loader to clunk when it changes from wash to spin?
Yes. Whirlpool documents it: “The drive system will make a knocking or thumping noise as it shifts from agitation mode to spin mode or vice versa.” One clunk at the mode change is the design. A repeating metallic noise during agitation or during spin is not.
Can I fit a gearcase from the same brand but a different model?
Only if the part number matches. Shaft length, spline, mounting pattern and seal diameter all vary, and two current Whirlpool gear cases with numbers one digit apart are different parts. The brand on the front of the machine tells you nothing useful here.
My machine is eleven years old and the transmission has gone. What should I do?
Almost certainly replace the machine. You would be fitting the most expensive part available for it, onto an appliance close to its average service life, for an expected gain of about five years — and that assumes nothing else fails in the meantime, which on an eleven-year-old washer is a strong assumption. Our how long does a washing machine last page has the distribution behind that number.
Look under the machine before you look at parts
In order, because the first step is free and decisive. Pull the washer out, get a torch underneath, and look for oil. If it is there, you have your answer and you should stop running the machine today.
If it is not, name the half of the cycle that still works and chase the cheap part that owns that symptom — the shift actuator, the agitator dogs, the lid switch, the water that never drained. Turn the basket by hand with the power off. Check for a coin between basket and tub before you believe any grinding noise.
If the gearcase survives all that, match the number off the old part, not the badge on the front. A direct-drive machine carrying one of the 3360629 family numbers takes the legacy transmission, and buy a coupler with it. A current Whirlpool-group top-loader takes whichever of the two Whirlpool gear cases matches its number — and they are genuinely different parts. A GE or Hotpoint takes the WH03X33729 assembly, which has the considerable advantage of arriving with the tub seal already in the box. And if the machine is past ten years old, do the arithmetic before you do the repair, because this is the part where it usually comes out against you.
