Refurbished and road tested AWF8G45 – Peugeot 2.0 HDI, Citroen, Opel transmission marking 20GM22, 20GM26, 20GM13, (1636385780, 1643637480, 9827156780, 1636385980, 9823499580, 9830763780) Warranty is 1 year

Phase 1: Solving K1/C1 Clutch Burnout with UA80E Components

The most notorious failure in the European AWF8G45 is the C1 (Forward) clutch pack burning out. This typically occurs because of a loss of hydraulic pressure when driving in cruising modes in higher gears.

The Root Cause
In the standard AWF8G45, the C1 drum is supported on the input shaft by only two points: a radial needle bearing and a plain bearing. Under sustained load in overdrive gears, this inadequate support allows for microscopic deflection. This deflection bleeds off the hydraulic pressure required to keep the K1/C1 clutches fully applied, resulting in clutch slip and catastrophic burnout.

The UA80E Retrofit Solution
Toyota engineers addressed this vulnerability in the UA80E/F (the Japanese equivalent of the 8G45) by redesigning the support structure. The UA80E utilizes much more robust bronze bushings and improved fluid routing that ensures hydraulic pressure remains entirely under the piston.

To permanently cure the 8G45, rebuilders can retrofit the K1 K2 drums and input shaft using the updated UA80E/F components.

Modification Steps:

• Input Shaft Modification: The UA80E input shaft requires minor modification to properly interface with the European 8G45 torque converter and stator. You must cut off the plastic ring housing, modify the torque converter lockup, and remove one of the four plastic rings at the front base of the shaft.
• Drum Integration: Install the UA80E C1 and C2 clutch drums. The superior bronze bushing support of the UA80 components effectively prevents the compression and pressure bleed of the C1 package in 6th–8th gears.
• Sealing: Discard the factory European seals and utilize the UA80E-compatible split O-rings (typically available in a 14-ring kit) to ensure proper sealing on the modified shaft.

Phase 2: Upgrading the C3/C4 Drum to Steel

The second major structural weakness of the AWF8G45 is the factory C3/C4 clutch drum.

The Root Cause
Aisin utilizes an aluminum C3/C4 drum from the factory to reduce rotational mass. Unfortunately, the aluminum splines are not durable enough to withstand the repeated torque loads of an 8-speed's frequent shifting profile. The steel friction plates eventually chew into the aluminum splines, causing the drum to groove. This damage causes hanging shifts, delayed engagement, and eventual pressure loss.

The Steel Drum Solution
Replacing the OEM aluminum C3/C4 drum with a heavy-duty aftermarket steel counterpart completely eliminates spline wear and adds much-needed rigidity to the clutch pack.

Assembly Best Practices:

• Clearance Verification: When installing the steel C3/C4 drum, ensure exact clutch pack clearances. A typical C4 pack utilizes four 1.50 mm friction plates and four 1.80 mm steel plates. The C3 pack generally requires three 1.45 mm frictions and two 2.00 mm steels.
• Hub Rings: Always replace the C3/C4 drum hub rings with new plastic sliding washers (outer Ø 74.05 mm, inner Ø 63.05 mm, thickness 3 mm). Reusing the OEM rings is a guaranteed way to introduce a pressure leak.