6F35 Overhaul Kit 2007-2012

This is a new overhaul kit for the early, first-generation Ford 6F35 six-speed automatic, the unit behind the 2.5L four-cylinder in the 2009-2012 Escape and Mercury Mariner and the four-cylinder Fusion and Milan of the same era. It is the reseal set: the gaskets, lip seals, O-rings, sealing rings and small rubber parts that go back into the case, pump and clutch circuits when the transmission is torn down. If your early 6F35 is weeping fluid, engages slowly on a cold morning, or slips and flares now that the miles are high, this is the base kit the repair is built on.

What the overhaul kit does in an early 6F35

The 6F35 has no bands. All six forward gears and Reverse come from five clutches (1-2-3-4, 3-5-R, 4-5-6, 2-6 and low/reverse), and every one of them is applied by line pressure routed through the pump, the case passages and rotating sealing rings on the input shaft and drums. That pressure is only as good as the rubber and Teflon holding it in. On a 2009-2012 unit that has seen years of heat, the seals take a set, the sealing rings wear, and pressure bleeds off before it reaches the piston, so a clutch that still has friction left applies late and slips. Replacing the whole set of seals and gaskets at once restores the sealing on every circuit, not just the one that leaked first.

What this kit includes and what it does not

• Included: gaskets, seals, O-rings, sealing rings and small rubber parts for the internal overhaul, per the kit listing
• Not listed: friction plates, steel plates, bonded pistons, the filter, bushings or hard parts

That matters on the 6F35 because several of its clutch pistons have rubber bonded straight onto the metal. With this kit you reuse your originals, so inspect every bonded lip before assembly. If one is hard, cut or lifting from the metal, buy new pistons before you start.

Symptoms that point to a reseal

• Fluid leaking from the case split line, pump seal area or side cover
• Long pause going into Drive or Reverse, worst when cold or after the car sits
• Shift flare once the fluid is fully warm
• Slip under load on a high-mileage unit
• Gear ratio codes P0731 through P0736 that come back after clearing

How to confirm before you buy

A teardown is a lot of labor, so rule out the simpler faults first. On the early 6F35, worn solenoid and pressure regulator bores in the valve body, a failing solenoid, a damaged harness at the case connector, or simply low or old fluid can all produce the same slip and late engagement. Our Ford 6F35 transmission problems guide lays out the order to check things. If the pan is full of friction material or metal, the job is a full rebuild with frictions and steels, and this kit becomes one part of that order. If the problem traces to the solenoids, the first-generation 6F35 solenoid set may fix it without opening the case.

Fitment

The kit maker lists this set for the early 6F35, 2007-2012. In practice Ford did not put the 6F35 into production vehicles until the 2009 model year, so on a real car this kit covers the Gen 1 units built from 2009 into 2012. Sonnax identifies Gen 1 by the casting numbers 9L8P or BL8P-7A100 on the valve body and solenoid body, and the second generation arrived during 2013 with internal changes. Kit makers split their overhaul sets at that line, so a 2013-up transmission needs the 2013-2014 6F35 overhaul kit instead. If your vehicle was built late in 2012 or early in 2013, check the casting before you order, or send us your year and VIN and we will confirm it. This kit is for the 6F35 only; the larger 6F50 and 6F55 use different seals. All of our parts for this transmission are on the 6F35 collection page.

Install notes

• Soak the new rubber seals in clean Mercon LV before assembly, and coat the sealing rings with assembly gel so they stay centered in their grooves while you stack the drums.
• Install lip seals with a driver that bears on the outer shell, never on the lip.
• Air-check every clutch circuit through the case passages before the valve body goes on. A hiss means a ring or seal is not seated.
• Inspect the pump bushing and the stator support while the pump is out. If they are worn, a renewed 6F35 front pump is cheaper than a comeback.
• Check the 4-5-6 drum for cracked or worn sealing ring lands; a scored drum will eat new rings. A loaded 2009-up 6F35 4-5-6 clutch drum is the fix if it is damaged.
• Refill with Ford Mercon LV only, then check the level hot with the engine running as the service procedure calls for.
• Clear adaptive learning with a scan tool after the rebuild and drive the car gently so the module relearns shift timing on the fresh seals.

Will this kit fit my 2008 Ford Escape?

Probably not. The 6F35 went into production for the 2009 model year. A 2008 Escape used a different automatic, so check the transmission ID tag before ordering. If you are unsure, send us the year and VIN.

Does this overhaul kit include frictions, steels or pistons?

No. The listing covers gaskets, seals, O-rings, sealing rings and small rubber parts. Frictions, steels, bonded pistons, the filter and bushings are not listed and should be ordered separately if your teardown shows they are worn.

How do I tell a Gen 1 6F35 from a Gen 2?

Gen 1 units carry casting numbers 9L8P or BL8P-7A100 on the valve body and solenoid body, and generally cover 2009-2012. Gen 2 arrived during 2013. If yours is a 2013 or later unit, use the 2013-2014 overhaul kit instead.

What fluid should I use after resealing a 6F35?

Ford specifies Mercon LV for every 6F35 application. Do not top up with older Mercon V or a universal fluid. Check the level hot with the engine running.

Do I need to reset anything after the rebuild?

Yes. Clear the transmission adaptive values with a scan tool, then drive gently through all gears so the module relearns shift timing for the new seals.

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