AWF21 Overhaul Kit

If your Ford Fusion, Mercury Milan, Lincoln MKZ, Mazda CX-7, CX-9 or Land Rover LR2 six-speed is coming apart for a rebuild, this AWF21 overhaul kit is the sealing side of the job. It is a gasket set plus sealing rings and seals for the Aisin TF-81SC, the six-speed front-drive unit Ford and Mazda call the AWF21 (also tagged AF21 and AW6A-EL). It is the no-piston version: it does not include frictions, steels or bonded pistons, so it suits a rebuild where the clutch packs and pistons check out good or are being bought separately.

What the overhaul kit does in an AWF21

The AWF21 shifts six gears using three clutches (C1, C2, C3) and two brakes, all applied by hydraulic pressure from the valve body. Every one of those circuits depends on a seal: the sealing rings on the shafts and drum hubs carry oil to the rotating clutches, the lip and metal-clad seals keep fluid in at the converter and axles, and the gaskets and O-rings seal the pan, valve body, cooler lines and pressure taps. When those age out you get pressure loss that the computer reads as slip, plus the leaks you can see. Precision's kit bulletin for this family notes the valve body gaskets are supplied to replace ones originally bonded to the plates, and the kits carry axle metal-clad seals for several models, cooler line and pressure tap O-rings, and valve body check valves and screens.

Symptoms that point to tired seals in an AWF21

• Fluid leaks at the axle seals, pan, cooler line fittings or converter seal
• Delayed engagement into Drive or Reverse after the car sits overnight
• Flare or slip on the 3-4 and 4-5-6 shifts that gets worse when hot
• Codes such as P0729, P0734 or P0735 (gear ratio errors), which can come from leaking circuits or from valve body wear
• Dark fluid with clutch debris, which means the job needs frictions as well as seals

How to confirm before buying

Gear ratio codes on this transmission do not automatically mean worn seals. Sonnax documents solenoid modulator bore wear in the TF-81SC valve body that causes the same slip and the same codes, so a valve body problem can look exactly like a sealing problem. Read our guide on Aisin slipping under load and the explanation of flare versus slip before you tear the unit down. If the fluid is clean and the problem is only shift quality, a replacement AWF21 valve body may be the fix. If the unit is already out and the frictions are burnt, the AWF21 master rebuild kit covers frictions and steels too.

Fitment

Precision's bulletin lists TF-81SC applications across the Ford Fusion, Five Hundred and Freestyle, Mercury Milan and Montego, Lincoln Zephyr and MKZ, Mazda6, CX-7 and CX-9, Hyundai Veracruz and Land Rover LR2, and notes there are slight variations from model to model while the case layout stays the same. That variation is mostly pan gasket and axle seal size, so match your pan shape and axle seal size before you start. One warning: the Volvo and Saab TF-80SC (AF40) looks almost identical but parts do not interchange, so make sure your unit is the AWF21/TF-81SC. Send us your year and VIN if you are unsure. Browse the rest of our Aisin transmission parts for the matching hard parts.

Install notes

• Soak lip seals and O-rings in clean ATF, and lube sealing rings with assembly gel so they sit centered when the drums slide on.
• Inspect the C1, C2 and C3 bonded pistons; this kit does not replace them, so a torn or hardened piston lip means sourcing pistons separately.
• Air-check each clutch and brake circuit through the case passages before the valve body goes on.
• Replace the filter at the same time with the AF21/AF40 filter and gasket kit.
• Fill with the ATF your owner manual specifies (Ford, Mazda and Land Rover specs differ), check level at the specified temperature, then run the adaptive relearn so shift timing resets.

Does this AWF21 overhaul kit include clutches and steels?

No. This is the gasket, sealing ring and seal kit only. Frictions, steels and the bonded C1, C2 and C3 pistons are not included. If your clutches are burnt, the AWF21 master rebuild kit is the better buy.

Will it fit my 2008 Ford Fusion?

The 2006-2009 Fusion with the six-speed automatic uses the Aisin AWF21 (TF-81SC), which this kit is built for. Pan gasket and axle seal size can vary between applications, so send your VIN if you want us to confirm before ordering.

Is the AWF21 the same as the TF-80SC in my Volvo?

They share a design but the parts are not interchangeable. The Volvo, Saab and Opel unit is the TF-80SC (AF40), while Ford, Mazda and Lincoln use the TF-81SC (AWF21). Buy the kit that matches your unit.

What else should I replace with the overhaul kit?

Always fit a new filter. Inspect the bonded pistons, bushings and the pump, which are separate parts. If the fluid showed clutch material, add frictions and steels. Many rebuilders also replace the valve body or its worn modulator valve on high-mileage units.

Do I need to do a relearn after installing it?

Yes. After a rebuild the stored shift adaptives no longer match the fresh clutches. Clear them with a scan tool and drive the relearn procedure for your vehicle so shifts come back crisp.

• Aisin Slipping Under Load
• Shift Flare vs Slip: What Is the Difference
• Aisin Harsh or Delayed Shifts
• Adaptive Relearn After a Valve Body or Rebuild