6F50 Shift Kit 2007-18

This is a new TransGo SHIFT KIT valve body repair kit for the 2007-2018 Ford 6F50 and the 6F55, the six-speed transaxles behind the 3.5L and 3.7L V6 engines in the Ford Edge, Flex, Taurus, Explorer and the Lincoln MKX, MKS and MKT. It is aimed at drivers dealing with shifts that alternate between harsh and mushy, a converter clutch that slips and shudders on the highway, or gear ratio codes that return no matter how often the fluid is changed. Because one TransGo kit covers the whole 2007-and-later 6F50 range, this listing suits early and late trucks alike.

What the shift kit does in a 6F50

The 6F50 has no mechanical shift valves for the driver to feel; the TCM picks each gear by commanding solenoids, which in turn meter oil to the clutches. That system depends on a regulated solenoid feed, a pressure that is meant to stay fixed whatever line pressure does. High mileage and heat wear the bore of the solenoid pressure regulator valve, the feed starts to move, and every solenoid output moves with it. The kit restores that circuit with a drop-in bushing and new valve that work in the existing worn bore. It also supplies a redesigned main pressure regulator valve with longer lands to deal with the same wear in the line pressure circuit, and a new relief system that takes the place of Ford's isolator valve stack and protects clutches and other hard parts from sudden pressure spikes. The parts in the photo are the valves, sleeves and springs from that kit; it does not include a separator plate.

Symptoms that point to this kit

• Erratic shift timing and feel, harsh on one shift and slipping on the next
• Converter clutch slip or shudder at steady cruise, often with P0741 stored
• Gear ratio errors such as P0731 through P0735 with no matching clutch damage
• Line pressure that reads high or low on a gauge at idle or stall
• Symptoms that begin after a hot tow or long climb and then fade once the fluid cools

How to confirm before you buy

Start with a code scan and look at what the TCM is seeing: commanded versus actual gear ratio and converter slip speed. Next pull a fluid sample. Black fluid that smells burnt or shows clutch material means friction damage is already done and the unit needs clutches, not just a valve body kit. If the fluid is clean but codes keep coming back, a line pressure test that drifts out of spec strongly suggests regulator bore wear. The 6F50 and 6F35 share their basic design, so our 6F35 and 6F50 diagnostic guide applies to both and explains how to separate a hydraulic problem from a failed clutch.

Fitment

This listing covers the 6F50 from 2007 through 2018, and TransGo also rates the same kit for the 6F55 used with EcoBoost and SHO engines. It will not fit the smaller 6F35 used with four-cylinder engines in the Escape and Fusion, which needs its own Gen 1 or Gen 2 kit. Check the ID tag on the transmission case, or send us your year and VIN and we will confirm the match. You will find the complete line of 6F50 and 6F35 parts on our 6F35/6F50 transmission page, including the 2007 6F50 shift kit listing.

Install notes

• Remove the valve body from the left side of the transaxle, transfer the solenoid body, and disassemble the valve body on a clean, lint-free bench.
• Follow the TransGo instruction sheet bore by bore. Discard the isolator valves the new relief system replaces; leaving them in defeats the relief system.
• Inspect the original separator plate and gaskets, since the kit does not include them. Replace any plate showing checkball craters or cuts.
• If several bores are scored too deeply to seal, a complete remanufactured 6F50 valve body is the faster fix. On a full rebuild, inspect the front pump bushing and stator splines, and replace a worn 6F50 front pump support.
• Fill with Mercon LV, check the level hot, clear adaptive shift data with a scan tool and road test until every upshift and downshift has relearned.

If your 6F50 has clean fluid and shifts that worsen as it heats up, this kit addresses the most common hydraulic wear point in the transmission.

Will this fit my 6F55 EcoBoost Flex or Taurus SHO?

Yes. TransGo rates this kit for all 6F50 and 6F55 transmissions from 2007 on. Confirm the transmission model on the case tag or send us your year and VIN.

Does it fit a 6F35 in an Escape or Fusion?

No. The 6F35 uses different kits, split into Gen 1 and Gen 2 designs. This kit is for the 6F50 and 6F55 only.

Is a separator plate included?

No. The kit supplies valves, bushings, springs and the relief system. Reuse the original plate if it is undamaged, or replace it if the checkball seats are worn.

Will it stop my torque converter shudder?

It corrects converter clutch slip caused by valve body wear. If the converter clutch lining itself is worn or glazed, the converter must be repaired as well.

Do I need to relearn the transmission afterward?

Yes. Clear the adaptive shift data with a scan tool and drive through every gear under varied throttle so the TCM can relearn clutch fill times.

What fluid does the 6F50 use?

Mercon LV. Avoid mixing in universal or older Mercon V fluids after the repair.

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