AW5550SN Transmission parts, repair guidelines, problems, manuals

AF33, AF23, FA57

Transmission general data

Number of gears Transmission Type Drive Torque (Nm) ATF (full capacity) L ATF (change) L ATF type
5 AT FWD 330 7,1 3,5 Type T-IV

The 5-speed automatic transmission AW55-50SN was developed by Aisin specialists at the end of the last century as an exclusive 5-speed automatic transmission for non-Toyota FWD vehicles with engines from 2 up to 3 liters. After update of the valve body and computer settings, this transmission as AF23 and AF33 was installed on GM models: Daewoo-Chevrolet (Captiva, Epica, Laketti ...), Saab, Opel and American Saturn and Suzuki. The testing of this unique transmission was performed since 2000 on Volvo cars (on C70, both the 40, 70 and S60s and S80s).

Part of the design solutions for this tranmsission are adopted from its successful predecessor - the 4-speed AW50-40. The transmission was so successful that even its competitors installed AW55 for their popular cars, simultaneously releasing their RE5R05A (JR507E) (Nissan-Jatсo) and 5L40E / 5L50E (GM-Europe).

What are you looking for?

Overhaul Kit | Friction Kit | Friction | Steel Plate | Steel Kit | Band | Solenoid Kit | Solenoid EPC | Solenoid TCC | Pump | Shaft | Drum | Valve body | Torque converter | Hub | Piston | Piston Kit | Planetary Gear | Filter | Gasket | Bushing | Seal | Bearing | Pressure Plate | Stator | Differential | Retainer | Inhibitor Switch | Instruction manual | TOOLS & ACCESORIES | Sensor

Which cars run with this gearbox?

Part type Expand

Technical issues and repair guidelines

The torque converter repair after running 200 thousand kilometers is a routine procedure. Repair kits of gaskets and seals for this transmission are produced by many manufacturers. Frictions are replaced by whole packages. Packages of clutches and brakes are designed in a fairly balanced manner and wear out at about the same time. The complete kit of frictions is also ordered when linings of remaining (unburned) clutches are soaked with burnt oil.The most popular parts for replacement are the pump seal and the pump cover bushing. The first problem occurs when operating in the oil starvation mode and with the wornout torque converter. Almost each overhaul is accompanied with the torque converter cutting and its subsequent rebuilding. The lock-up friction lining wears out quite rapidly causing many issues in the AW55-50.

There are many signs of the faulty valve body, but the reason for the majority of premature (before 150-200 thousand kilometers) problems of the mechanical components in this transmission lies in insufficient pressure of the ATF coming from the valve body. Dirt in the ATF and high temperatures, wear out and clog channels of valves and solenoids of the valve body. Worn-out areas are clogged with dirt and plungers get wedged, so the ATF does not reach clutch packages and the torque converter lock-up.The valve body repair and cleaning should be performed as early as possible (when you notice the first signs of improper operation) in order to avoid typical and fatal problem, namely the valve body housing wear-out. For rebuilding of transmission units in "old" cars, specialists usually order the kit of frictions, steel discs, and repair kit of gaskets and seals (overhaul kit). At the same time specialists replace the brake band (because friction linings are soaked with burnt oil). The pressure shortage from oil, coming from clogged valve body may have a negative impact on bushings. The pump cover bushing is the first to wear out. In rare cases planetary gear bushings are pressed out.

Mechanical elements of the AW55-50SN transmission are very reliable or even may be called “flawless”. The evidence of reliability lies in the factor, that for 90% cases of transmission components repair, specialists order only the repair kit of bushings. But if a driver frequently overloads the transmission, then repair specialists sometimes have to rebush or replace worn-out rear planetary gear.