Replaces the worn 47-tooth differential gear housing inside the TF-81SC (AF21) transaxle in Ford Fusion, Lincoln MKZ, Mazda CX-9 and Hyundai Veracruz.
When a Ford Fusion, Lincoln MKZ, Mazda CX-9 or Hyundai Veracruz with the Aisin six-speed starts to growl with road speed, clunks in tight turns, and leaves glitter on the pan magnet, the final drive is often the culprit, not the clutches. This is the differential case for the Aisin TF-81SC transaxle, also sold under the names AF21 (Ford) and AW6A-EL (Mazda). It is the cast housing that carries the final drive ring gear, the spider and side gears and the pinion shaft. It is listed as the 47-tooth version, and it replaces OE reference 45822-24000.
The TF-81SC is a transverse six-speed, so the differential lives inside the transaxle case and runs in the same ATF as the clutches and planetaries. Torque comes off the gear train through the transfer gears and into the final drive ring gear, which bolts to the flange on this case. The case spins, and the pinion shaft and spider gears inside it split the torque between the two front axles. The photos show the bolt flange, the windows for the spider gears, a long splined hub on one side, and a tapered roller bearing pressed onto that hub. The ring gear is not included; it moves over from your old case.
Harsh 2-3 shifts, flare and converter shudder are the TF-80SC/TF-81SC family's better-known problems, and they come from the valve body and solenoids, not the differential. Our TF-80SC and TF-81SC problems guide and the Ford Fusion transmission guide cover those so you do not chase the wrong noise.
Raise the car and run it in gear on stands. A final drive noise follows wheel speed and does not change when the transmission shifts. Turn one front wheel by hand with the other on the ground and feel for notching. Drop the pan and look at the debris. The real answer comes when the case is split: a pinion shaft bore that is worn oval, scored thrust faces behind the side gears, or a cracked flange means the case has to be replaced. See how to tell transmission noise from differential noise for a step-by-step process.
The listing covers the Aisin TF-81SC (TF-80, TF-81, AF21, AW6A-EL) in 2005-2006 Ford Five Hundred 3.0L, 2006-2007 Ford Fusion 3.0L, 2007 Ford Mondeo 2.0L, 2007-2011 Lincoln MKZ 3.5L, 2009-2011 Mazda 6 3.7L, 2007-2011 Mazda CX-7 2.3L, 2007-2011 Mazda CX-9 3.5L and 3.7L, and 2007-2011 Hyundai Veracruz 3.8L. These transaxles were built with more than one final drive ratio and in FWD and AWD versions, so lay the old case next to the photos: count the teeth on your ring gear, match the bolt pattern and the splined hub, and check the 45822-24000 reference if your case has it. Not sure? Send us your year and VIN. More TF-81SC parts are on our Aisin transmission page.
The transaxle has to come out and the case split to reach the differential. Lift the differential out, unbolt the ring gear, and move it and the spider gears to the new case if they are in good shape. Use new ring gear bolts if the old ones are stretched or were locked with sealant. Set the carrier bearing preload with the selective shim before you close the case, and replace the carrier bearings and both axle seals while you are in there; the TF-80SC/TF-81SC gasket and seal overhaul kit has the seals. A full rebuild at the same time makes sense, since the metal from the differential has run through the whole unit; the TF-80SC master rebuild kit and a fresh filter and pan gasket kit cover the rest. Refill with the ATF your owner's manual lists (the Aisin base spec for this family is a JWS 3309-type fluid) and check the level hot.
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No. The photos show the bare case with a tapered bearing on the splined hub. Your ring gear bolts onto the new case, and that is why the tooth count has to match.
It identifies which final drive version this case is listed for. The TF-81SC was built with more than one final drive ratio, so count the teeth on your old ring gear and compare the hub and bolt pattern before ordering.
Yes. Aisin builds it as the TF-81SC, Ford calls it the AF21 (AWF21), and Mazda uses AW6A-EL. The TF-80SC (AF40) in Volvo, GM and Saab models is a close relative with different parts.
The listing fitment for Fusion is 2006-2007 3.0L. For other years, send us your VIN and the transaxle tag, or compare your old case to the photos before ordering.
Replace the carrier bearings, both axle seals and the filter, and flush the cooler. If metal has gone through the unit, a full overhaul kit is the safe choice.
Use the ATF your owner's manual lists for the vehicle and check the level at operating temperature. The differential shares this fluid with the rest of the transaxle.
