Master overhaul kit for the Toyota A340E/A340F/A340H/A343F 4-speed: frictions, steels, gaskets, seals and O-rings for 4Runner, Supra and Cressida.
A Toyota 4Runner that flares between gears, a Supra that hesitates before overdrive, or a Cressida that takes a second or two to grab reverse is usually telling you the same thing: the clutch packs inside the Aisin-built A340 four-speed are worn and the rubber that holds pressure on each piston has gone hard. This master overhaul kit is the parts side of a full rebuild for that transmission family. It covers the A340E, the A340F and A340H four-wheel-drive versions, and the A343F, and it puts new friction plates, new steel plates and a complete seal and gasket set on your bench in one box.
The A340 is a Simpson-style gearset with an overdrive unit bolted on the front. Every gear change is a hand-off between hydraulic clutches and brakes: the forward clutch drives the first three gears, the direct clutch and second brake take over for the upshifts, the low and reverse brake holds the rear planetary in first and reverse, and the overdrive section has its own clutch and brake. Each of those packs has a piston that must seal against its drum, and each pack has frictions that wear a little every shift. The photo shows what comes in this kit: four stacks of friction and steel plates, sealing rings and piston seals bagged by circuit, front and rear seals, O-rings, thrust washers and the full gasket set including a cork pan gasket.
That matters because the A340 has a known wear order. Independent teardown data lists the forward clutch as the pack that burns first, followed by the second brake and then the low and reverse brake, and it ties dirty fluid to bushing wear and a slow loss of oil pressure across the whole unit. A kit with only seals would not address glazed or burnt frictions; this one replaces both.
Rule out the cheap causes first. Check the fluid level hot with the engine idling, and look at the fluid color and smell. Scan for stored codes: a shift solenoid or wiring fault on an electronic A340 can feel a lot like a slipping clutch, and a bad ground has fooled more than one shop into an unneeded rebuild. If the codes are clean and the pan holds clutch material, the fault is mechanical and a teardown is the next step. Our guide to Aisin slipping under load walks through the pressure and stall checks that separate a worn pack from a hydraulic problem. If fluid is simply old and the unit still shifts well, a proper Toyota transmission service may be all it needs.
This kit is listed for the A340E, A340F, A340H and A343F transmissions in these vehicles:
The A340 family ran for decades and Toyota changed clutch counts and some drum details between the two-wheel-drive and four-wheel-drive cases and between early and late units, so the transmission model on the case tag matters more than the vehicle name. Read the tag on the side of the case, or send us your year, model and VIN and we will check it before it ships. Other A340 parts, including valve bodies and pumps, are in the Aisin and Toyota transmission collection.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for the A340E, A340F, A340H and A343F. Clutch counts can differ between two-wheel-drive and four-wheel-drive cases and between early and late years, so check the model on your transmission tag or send us your year, model and VIN before ordering.
Friction plates, steel plates, gaskets, piston seals, sealing rings and O-rings, as shown in the product photo. Bands, bushings, a filter and hard parts such as drums and planetaries are not included.
Toyota specifies Type T-IV ATF for the A340E, with a total capacity of about 8.3 liters. Soak the new frictions in the same fluid before assembly and set the level with the transmission at operating temperature.
The forward clutch tends to burn first, followed by the second brake and then the low and reverse brake. Expect to find the worst wear in those packs when you open the unit.
Inspect the pump bushing and gears; dirty fluid wears the bushing and drops pressure, so replace the pump if it is scored. The converter should be flushed or replaced because it holds old fluid and friction debris that will contaminate the new clutches.
