A750F Tcc Solenoid 2003-09

A 2005 Tundra with the 4.7L V8 and A750F is the textbook case of how a lockup code can eat money: Transmission Digest wrote up one that kept setting P2757 through a salvage transmission, a new converter, a second valve body and a new solenoid. If your 2003 to 2009 4x4 Toyota or Lexus five-speed has a lockup complaint, this page explains what this remanufactured SLU torque converter clutch solenoid fixes, and how to make sure it is the part your truck actually needs.

The SLU's job in a 2003-09 A750F

The A750F is the four-wheel-drive version of Aisin's five-speed, with a transfer case on the tail. Its converter clutch is controlled by the SLU, a current-controlled linear solenoid in the valve body. At lower speeds the computer runs a partial apply called flex lockup, holding the clutch with a little controlled slip for smoothness. Higher up, in 4th and 5th, it commands full lock. On the Tundra in that article the SLU signal measured roughly 3.5 volts during flex lockup and 7.0 volts at full lockup above 45 mph, which gives you a real number to check against.

Symptoms on a 4x4 A750F

• Shudder between about 32 and 42 mph that goes away when you press harder or select a lower range, a sign of flex lockup trouble
• Engine RPM flaring slightly at cruise instead of staying locked
• P2757, often after a long highway drive rather than right away
• Higher fluid temperatures when towing or off-road

Before you buy: rule out the fluid and line pressure

The Tundra in the Transmission Digest case had factory WS fluid, and the article points out that WS can degrade around 40,000 miles, bringing on flex lockup shudder that a simple fluid change often cures. Line pressure is the other suspect: TransGo notes that a worn aluminum pressure regulator boost valve in the A750 causes low line rise, TCC slip and P2757. So do the cheap checks first. Change the fluid and filter, check the SLU signal with a voltmeter, and only then replace the solenoid. Our TCC shudder diagnosis article covers the road test, and Aisin overheating prevention explains why a slipping converter is hard on the rest of the unit.

Fitment, 2003-2009

This listing covers the A750F from 2003 through 2009, with the 2WD A750E as a reference. In that window the A750F went into 4x4 versions of trucks such as the 4Runner, Tundra and Sequoia with the 4.7L, Tacoma, FJ Cruiser and Lexus GX470, depending on model year and engine. Solenoid changes over the production run are not always obvious, so compare the connector and body of this part with the one on your valve body before installing. For later trucks, see the A750F TCC solenoid listed without a year range. Send us your year and VIN if you want us to check fitment. More A750 parts are in our Aisin collection.

Install notes

• Remove the skid plate if fitted, drain the fluid and drop the pan and filter.
• Identify the SLU by its harness lead before disconnecting anything; the A750 valve body carries several similar solenoids.
• Pull the bracket and solenoid, inspect the screen, and replace the O-ring with the one supplied on the new part.
• Refill with Toyota WS ATF only, check the level hot through the overflow plug, and road test until lockup engages at highway speed in 5th.

If the valve body shows wear, pair this solenoid with the A750E/F shift kit for 2005-2015 or a replacement 2005-2009 valve body. Heavy debris in the pan points to an overhaul instead.

Which trucks use the A750F from 2003-2009?

Four-wheel-drive versions of Toyota and Lexus trucks with the A750 five-speed, such as the 4Runner, Tundra and Sequoia 4.7L, Tacoma, FJ Cruiser and GX470, depending on year and engine. Send your VIN if you want us to confirm.

Why does my truck only shudder between 32 and 42 mph?

That is the flex lockup range, where the converter clutch is applied with controlled slip. Degraded WS fluid commonly causes shudder there. Change the fluid before replacing parts.

How can I test the SLU solenoid on the truck?

With a voltmeter across the SLU wires, look for about 3.5 volts during flex lockup and about 7.0 volts at full lockup above 45 mph, as documented in a Transmission Digest case on a 2005 Tundra A750F.

What else should I replace with it?

Always the filter and fluid. If line pressure is low or the valve body is worn, a shift kit or valve body may be needed to fully cure TCC slip.

What fluid goes back in?

Toyota WS ATF. Set the level at operating temperature using the overflow-plug method.

• Torque Converter Clutch Shudder Diagnosis
• Aisin Overheating Prevention
• Torque Converter Stall Test and Lockup Diagnosis
• Toyota Camry and Tacoma Transmission Service