The Y85 F77 torque converter is the specific unit required for the 2.7L V6 Diesel (AJD-V6) engine paired with the ZF 6HP26 6-speed automatic transmission. This setup was standard in the Jaguar S-Type and Jaguar XJ (X350/X358) between 2004 and 2009.

1. Identification & Compatibility

The “Y85 F77” code is critical because torque converters for the 2.7D are not interchangeable with those from the 3.0L V6 or 4.2L V8 gasoline models.

• Engine Match: Specifically for the Ford/PSA 2.7L Twin-Turbo Diesel.

• Stall Speed: The diesel unit has a unique stall speed and internal damper assembly designed to handle the high low-end torque ($435\text{ Nm}$) of the diesel engine.

• Cross-Reference: You may also see this listed under Land Rover/Range Rover parts (Part #LR008767) as the Discovery 3 used the same engine/gearbox combination.

2. Common Failure: The “S-Type Squawk”

The 2.7D 6HP26 setup is notorious for a “squawk” or “whoop” noise during the 3-4 gear shift.

• The Cause: Glazing of the internal lock-up clutch friction material within the torque converter.

• The Fix: While a fluid flush with ZF Lifeguard 6 and a friction modifier (Sturaco) can sometimes temporarily mask the noise, a permanent fix usually requires a rebuilt or new torque converter.

3. Market Value (February 2026)

Because this is a specialized diesel part, prices vary depending on whether the unit is used or professionally remanufactured (which involves cutting the unit open, replacing the friction lining, and re-welding).

4. Technical Checklist

• Stator Spline Count: 43

• Pilot Diameter: 1.375″

• Mounting: 4-bolt pattern.

• Transmission Fluid: You must use ZF Lifeguard 6 or a fluid meeting Shell M-1375.4 specifications. Using incorrect fluid will cause the new converter’s lock-up clutch to fail prematurely.