Master rebuild kit for Toyota A340E, A340F and A340H: overhaul gaskets and seals plus friction and steel plates for 4Runner, Tacoma, Tundra, Supra.
A 4Runner that slips into third under load, a Tacoma that flares on the 2-3 shift while towing, or a Tundra that takes a second to engage Reverse are all typical of an A340 family transmission with worn clutch packs. This master rebuild kit is the parts side of the overhaul: a complete overhaul gasket and seal kit plus a full set of friction plates and a full set of steel plates. The seal kit comes bagged by circuit, with separate bags labeled for the overrun clutch, overrun brake, direct clutch, low and reverse brake and the accumulators, which makes reassembly far easier to keep straight.
The A340E is Toyota and Aisin's four-speed rear-drive electronic automatic, and the A340F and A340H are its four-wheel-drive versions. Two shift solenoids select the gears, but the actual work is done by clutches and brakes applied by line pressure. When the frictions glaze or the steels heat-check, or when sealing rings and piston seals harden, a pack can no longer hold torque and the unit slips or flares. Industry teardown notes for this unit say the forward clutch usually burns first, followed by the second brake and then the low and reverse brake. This kit replaces all of those wear surfaces and every rubber seal in one job.
Rule out the electrical side first. A stored shift solenoid code such as P0750 or P0755 on a 1996 and later truck points to a solenoid, its wiring or a ground, not the clutches, and one documented 2002 Tacoma case traced a P0755 to a loose ground. If the codes are clear, check the fluid hot, drop the pan and look for debris, then road test and note which shift slips. Our guides on Aisin slipping under load and harsh and delayed shifts walk through those checks. If the solenoids are the problem, a shift and TCC solenoid kit with filter is the smaller repair.
The listing names the A340, A340E, A340F, A340H, A341E and A343F, with applications including the 1989-2004 4Runner, 1995-2012 Tacoma 2.7L, 3.0L and 3.4L, 1999-2004 Tundra, 2001-2004 Sequoia 4.7L, 1993-1998 T100, 1985-1995 Toyota Pickup, 1995-2002 Land Cruiser, 1986-1998 Supra, 1987-1992 Cressida and 1993-1997 Previa. Two cautions: the 2003-2004 4Runner V8 uses a five-speed, and clutch pack counts can vary between two-wheel and four-wheel-drive units and between engine applications. Count your old plates during teardown and compare before you build. Read the code on the case ID plate, and if anything does not match, send us your year and VIN. More parts for this family are in our Aisin transmission collection.
Before anything goes back together, inspect the pump bushing and body, drum bushings and the planetary carriers; dirty fluid on these units wears bushings and drops oil pressure, and new frictions will not survive low pressure. A worn pump can be replaced with an A340E oil pump assembly, and a carrier with chipped teeth or loose pinions with an A340E planetary. Soak all new frictions in clean ATF for 30 minutes or more, stack each pack and measure clearance with a feeler gauge, correct with selective plates, and air-check every circuit before installing the valve body. Refill with Dexron-type or Toyota T-IV fluid as specified for your model year, set the level hot, and keep the first few hundred miles easy while the frictions seat.
| Fits | Toyota/Aisin A340, A340E, A340F, A340H, A341E, A343F |
| Includes | Overhaul gasket and seal kit, friction plate kit, steel plate kit |
| Weight | 9.97 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for the 1989-2004 4Runner with the A340 family. The 2003-2004 V8 4Runner uses a five-speed and will not take it. Check the code on the case ID plate, or send us your year and VIN.
Clutch pack counts can differ between 2WD and 4WD units and between V6 and V8 versions. Count the plates in each of your old packs during teardown and compare them to the kit before you start stacking.
An overhaul gasket and seal kit with circuit-labeled bags, a full set of friction plates and a full set of steel plates. Bushings, a filter, a torque converter and hard parts are not included.
Early A340 trucks were filled with Dexron-type ATF and later Toyota applications with Type T-IV. Use what your owner's manual specifies and check the level hot.
If a shift solenoid code is stored and the fluid is clean, try the solenoids first. If the fluid is burnt or the pan has friction debris, the packs are worn and a full rebuild is the real fix.
