What transmission does this TCC lockup issue affect?

The document applies to some 2005-2010 vehicles equipped with a 4R70/75E-W transmission.

What are the symptoms of the un-commanded TCC apply?

TCC apply or partial apply immediately after the 1-2 shift, a perception of lacking power or early upshifting, uncommanded TCC apply when coming to a stop before the 2-1 downshift, engine stalling or lugging when engaging manual 2nd at a stop, and code P1742 in continuous memory. The vehicle operates normally in Park, Reverse, Neutral and manual 1st gear.

What diagnostic trouble code is associated with this issue?

Code P1742 may be present in continuous memory.

How do you verify the TCC problem per this procedure?

Monitor TCC % solenoid command state duty cycle and TC SLIP ACT (torque converter clutch slippage in RPM) in 2nd, 3rd or 4th gear with TCC % reading 0. If TCC % = 0 and TC SLIP ACT is less than 20 RPM, inspect the number 7 check ball in the main control valve body for damage.

What part should be inspected if TC SLIP ACT is under 20 RPM with TCC % at 0?

The number 7 check ball in the main control valve body should be inspected for damage and replaced as required per the Workshop Manual's Main Control Valve Body disassembly and assembly section.

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4R70/75E-W Uncommanded TCC Apply Service Procedure 2005-2010 - Code P1742

Service bulletin with Issue, Action, and numbered Service Procedure steps

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Service procedure for diagnosing torque converter clutch slippage with issue, action, and numbered diagnostic steps.

AI caption December 2015 · Photo 2744 of 2796

This document is the first page of a service procedure (TSB-style) addressing an un-commanded torque converter clutch (TCC) apply or partial apply on some 2005-2010 vehicles equipped with the 4R70/75E-W automatic transmission. The issue occurs immediately after the 1-2 shift and may be perceived as a lack of power or the transmission upshifting too early. Additional symptoms include uncommanded TCC apply when coming to a stop before the 2-1 downshift is commanded, engine stalling or lugging when engaging manual 2nd while stopped, and diagnostic trouble code P1742 stored in continuous memory. The vehicle should still operate normally in Park, Reverse, Neutral, and manual 1st gear. The service procedure directs the technician to monitor the TCC % solenoid command state duty cycle and TC SLIP ACT (torque converter clutch slippage in RPM) while in 2nd, 3rd, or 4th gear with TCC % reading 0. If TCC % equals 0 and TC SLIP ACT is less than 20 RPM, the number 7 check ball in the main control valve body should be inspected for damage and replaced as required, following the Workshop Manual procedures for Disassembly and Assembly of Subassemblies – Main Control Valve Body (referencing Fig 1). This appears to be page 1 of a multi-page procedure.

This document covers 2005-2010, which may differ from this 2000 Mercury Grand Marquis.

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Frequently asked questions

What transmission does this TCC lockup issue affect?: The document applies to some 2005-2010 vehicles equipped with a 4R70/75E-W transmission.
What are the symptoms of the un-commanded TCC apply?: TCC apply or partial apply immediately after the 1-2 shift, a perception of lacking power or early upshifting, uncommanded TCC apply when coming to a stop before the 2-1 downshift, engine stalling or lugging when engaging manual 2nd at a stop, and code P1742 in continuous memory. The vehicle operates normally in Park, Reverse, Neutral and manual 1st gear.
What diagnostic trouble code is associated with this issue?: Code P1742 may be present in continuous memory.
How do you verify the TCC problem per this procedure?: Monitor TCC % solenoid command state duty cycle and TC SLIP ACT (torque converter clutch slippage in RPM) in 2nd, 3rd or 4th gear with TCC % reading 0. If TCC % = 0 and TC SLIP ACT is less than 20 RPM, inspect the number 7 check ball in the main control valve body for damage.
What part should be inspected if TC SLIP ACT is under 20 RPM with TCC % at 0?: The number 7 check ball in the main control valve body should be inspected for damage and replaced as required per the Workshop Manual's Main Control Valve Body disassembly and assembly section.