6F35 Sprag Clutch

When a Ford Escape, Fusion, Lincoln MKZ or four-cylinder Edge, Explorer or MKC with the 6F35 six-speed sits in Drive and will not pull away, flares on launch, or feels like it is in neutral until it grabs second, the low one-way clutch is one of the first hard parts to suspect. This remanufactured 6F35 sprag clutch is the low one-way clutch assembly shown in the photos, with its lugged outer race, cleaned, inspected and ready to go back into the case.

What the low one-way clutch does in a 6F35

The 6F35 builds first gear in Drive with only one hydraulic clutch: the 1-2-3-4 (forward) clutch. The reaction side of the gearset is held by the low one-way clutch, which locks against rotation in one direction and overruns in the other. TransGo's application chart for the 6F35 shows the low/reverse clutch can be applied at a stop but is released before the 1-2 shift, so once the vehicle is rolling in first, the one-way clutch alone is carrying the reaction torque. That is also why the 1-2 upshift is so smooth on this unit: when the intermediate (2-6) clutch comes on, the one-way clutch simply starts to freewheel and no clutch has to be timed off.

Symptoms of a worn or slipping 6F35 one-way clutch

• No movement or a long delay in Drive from a stop, while Reverse still works
• Engine flares on takeoff, then the vehicle catches once it shifts into second
• First works when the low/reverse clutch is commanded on (manual low or SelectShift 1 where equipped) but not in Drive
• Clunk, ratchet or grinding noise on light throttle or when coasting down to a stop
• Gear ratio error codes for first gear, often alongside metal in the pan

Keep in mind the 6F35 is also known for valve body bore wear and solenoid faults, and low line pressure can make the forward clutch slip in first with the same feel as a bad one-way clutch.

How to confirm before you order

Scan the TCM for codes and check fluid level and condition first. Then compare first in Drive against first with the low/reverse clutch applied: if the vehicle drives normally when the low/reverse clutch holds the reaction member but slips or freewheels in Drive, the one-way clutch is the likely culprit. If first slips both ways, look at the forward clutch and its pressure circuit instead. Our guide to Ford 6F35 transmission problems covers the regulator valve wear that causes many of those pressure complaints. On teardown, check the rollers or sprag elements for flat spots and the race surfaces for pitting or bluing.

Fitment

This listing is for the Ford 6F35 transaxle used from about 2009 through 2019. The 6F35 went through several generations, and this listing does not specify a year range, so do not order on the vehicle name alone. Compare the outer race diameter, the number and spacing of the outer lugs, and the race width against the unit you removed, or send us your year and VIN and we will check it for you. If your build is an early 2009 unit, also look at our 6F35 sprag clutch for 2009. Do not substitute a 6F50 one-way clutch; the larger transaxle uses a different assembly. Everything we carry for this transmission is on the 6F35 parts collection.

Install notes

• Before installing, hold the outer race and confirm the assembly locks in one direction and spins freely in the other; installed backwards it will lock in the wrong direction and the unit will bind.
• Inspect the mating inner race; if it is pitted, scored or heat-colored, replace it, because a new clutch will not hold on a damaged race.
• A slipping one-way clutch usually leaves debris through the unit, so most rebuilders refresh the clutch packs at the same time with a 6F35 master rebuild kit for 2009-2017.
• If the forward or low/reverse frictions are glazed or burned, pair it with the 6F35 friction clutch plate kit.
• Flush the cooler and lines, refill with Mercon LV only, and check the level hot at the check plug.
• Clear the transmission adaptive tables and drive through several gentle launches and 1-2 shifts so the TCM can relearn.

Is a sprag clutch the same as the low one-way clutch?

In the 6F35 they are the same job. This part is the low one-way clutch assembly that holds the gearset in first gear in Drive and freewheels once second gear engages.

How do I know the one-way clutch is the problem and not the forward clutch?

If first works with the low/reverse clutch applied but slips or freewheels in Drive, the one-way clutch is the likely fault. If first slips either way, check line pressure, the valve body and the forward clutch first.

Will this fit my vehicle?

It fits the Ford 6F35 transaxle. The unit changed across generations, so match the outer race size and lug pattern to your old part, or send your year and VIN before ordering.

What fluid does the 6F35 use after the repair?

Ford specifies Mercon LV for the 6F35. Do not mix in multi-vehicle fluids, and check the level hot at the check plug.

Do I need to relearn the transmission after installing it?

Yes. Clear the TCM adaptive values with a scan tool and then make several light-throttle launches and upshifts so the shift timing relearns.

Is this new or used?

It is a remanufactured assembly, inspected and ready to install.

• Ford 6F35 Transmission Problems: Real Causes and the Fixes That Last