A341E Master Rebuild Kit

Owners searching for an A341E rebuild kit are usually nursing a 1990s Lexus V8 or inline-six: an LS 400 or SC 400 that has started to slip into overdrive, a GS 300 that shudders and jerks between gears, or any of them dripping fluid from tired seals. The A341E (Toyota code 30-41LE) is the rear-drive four-speed Aisin built for those cars, and this master rebuild kit replaces its wearing parts in one order. Per the kit's listing it holds a complete overhaul kit plus a 28-piece friction set and a 28-piece steel set, with component numbers B073820CS, B073880B and W073881B. The product photo shows the valve body separator gaskets, cork pan gasket, case gaskets, lip seals, O-rings, sealing rings and plastic thrust washers alongside the plates.

What the master kit does in an A341E

The A341E runs ratios of 2.531, 1.531, 1.000 and a 0.705 overdrive, with every range applied by a multi-plate clutch or brake fed by line pressure. Twenty-eight frictions and twenty-eight steels is a lot of clutch surface, and in a high-mileage unit every pack has worn and glazed at about the same rate. Replacing them all at once, together with the seals and sealing rings that hold apply pressure, puts the whole unit back on the same starting line. The kit is aimed at the standard AW30-41LE; a reinforced 30-41LS version also exists, so a unit with a different internal stack needs checking before you order.

Symptoms that call for a rebuild

• Slipping into overdrive or on the 3-4 shift at highway speed
• Delayed or soft engagement into Drive or Reverse
• Jerky, harsh shifts after torque converter lockup clutch debris has packed into the valve body
• Burnt fluid with friction material on the pan magnet
• Fluid leaks from the front pump seal, rear seal or pan on a high-mileage unit
• Vibration under lockup that has started to wear the oil pump bushing

How to confirm before you buy

Check the fluid level hot and smell the fluid; burnt, dark fluid with debris points to worn clutch packs. Many of these cars predate OBD-II, so rule out the electrical side by testing the two shift solenoids and the lockup solenoid rather than relying on codes. If a solenoid is open or sticking, a replacement A341E shift solenoid may cure the shift complaint without a teardown. Our guide on Aisin slipping under load covers pressure loss versus worn frictions, and Aisin overheating prevention explains why heat finishes off old clutch packs.

Fitment

The kit is listed for the A341E 30-41LE in the 1990-1997 Lexus LS 400, 1992-1997 Lexus SC 400, 1993-1995 Lexus GS 300, 1998-2000 Lexus SC 300 and 1993-1998 Toyota Supra. Be careful with that list. Published application data assigns several Supra and SC 300 years, and the early LS 400, to the closely related A340E (30-40LE) instead, lists the 1998-2002 LX 470 with the four-wheel-drive A343F, and does not list the GS 400 as an A341E car. The kit's listing names those vehicles too, but we do not recommend ordering for them without confirming the transmission code. Read the tag on the case, or send us your year and VIN and we will check it. More Toyota and Lexus parts are on our Aisin collection page, and the A341E master kit for the SC 400 is a second option for the same unit.

Install notes

• Drop the pan and valve body first. Published failure notes say lockup clutch debris clogs A341E valve bodies, so clean every bore or swap in an A341E valve body.
• Inspect the oil pump bushing and gears. Vibration from a worn lockup clutch destroys that bushing, and a remanufactured A341E pump is cheaper than a second rebuild.
• Planetary gear sets do not tolerate low oil pressure, so check them for heat discoloration and pinion end play.
• Soak the 28 frictions before assembly, stack them with the new steels, and set every clutch and brake clearance to the factory spec. Fit the new thrust washers and air-check each circuit.
• Refill with Toyota Type T-IV or an approved equivalent such as our T-IV type fluid. Published capacity is about 8.0 L for a dry unit, so check level hot on the dipstick rather than pouring a fixed amount.
• If the torque converter shows lockup shudder or debris, have it serviced or replaced at the same time so it does not contaminate the new clutches.

Does this kit fit my Toyota Supra or Lexus SC 300?

It is listed for them, but published data shows many of those cars use the A340E (30-40LE) instead of the A341E. Check the code on your transmission tag or send us your year and VIN first.

What is included?

An overhaul kit (gaskets, seals, O-rings, sealing rings and thrust washers), a 28-piece friction set and a 28-piece steel set. Pistons, bushings, the filter and hard parts are not included.

Will it fit the LX 470?

The LX 470 uses the four-wheel-drive A343F according to published application data. Do not order this kit for an LX 470 without confirming your unit.

What fluid does the A341E take?

Toyota Type T-IV or an approved equivalent. Fill to the hot mark on the dipstick.

My A341E shifts harshly but does not slip. Do I need a full rebuild?

Not always. Harsh, jerky shifts can come from lockup clutch debris in the valve body or a sticking solenoid. Test the solenoids and inspect the valve body before buying a full kit.

• Aisin slipping under load
• Aisin overheating prevention
• Aisin harsh and delayed shifts
• Shift flare vs slip: the difference