Symptoms:

  • No lockup
  • Code 894, 1870
  • Falls out of lockup when hot
  • Fluid blown out fill tube
  • Lockup immediately after 2nd gear

Cause:

Excess pump bore-to-valve clearance allows TCC signal oil to leak past the spool, preventing lockup or causing lockup to disengage when hot. Additionally, converter feed can leak past the excessive clearance, combine with signal oil and cause premature lockup.

Correction:

Sonnax improved drop-in TCC apply valve kit with PTFE seal will eliminate bore cross-leakage.

Warning:

This part only fits PWM units, and mismatching PWM and non-PWM valves will cause rapid converter failure.

Identifying PWM vs. Non-PWM Units
If the OE valve features one spool at the location indicated here, you are working on a PWM unit. If the OE valve features double spools, you are working on a non-PWM unit and must use Sonnax TCC apply valve kit 77805-K. Do not rely on the OE valve material (steel vs. aluminum) to determine for whether the unit is PWM, as some early PWM pumps used steel TCC valves like the non-PWM pumps.

4L60-E, 4L65-E, 4L70-E

TCC Apply Valve Kit
Part No. 77805E-K

Fits PWM units only.

View Instructions Find a Distributor

Vehicles with GM 4L60-E, 4L65-E and 4L70-E transmissions have numerous converter overheat lockup complaints. These include no lockup or lockup immediately after 2nd Gear when fluid warms up, caused by valve bore wear. Frequently, the solenoid will have no control over the valve's position. Often converter feed oil will leak past the OE spool, which, added together with orificed signal oil will be more than the solenoid can exhaust. This may completely stroke the valve into the lockup position and create a "no power" or "no brake cancel" condition. Oil cross-leaks may float the valve into a mid-way position and restrict cooler flow, which burns up the converter. Sonnax TCC apply valve kit 77805E-K will eliminate the bore cross-leakage. This precision valve has a PTFE seal to prevent the cross-leaking of converter signal and converter feed oil.

  • Updated stroke pressure eliminates TCC drift on apply and updated exhaust control
  • PTFE seal eliminates cross-leaking of converter signal oil and converter feed oil
  • Works in both early- and late-style PWM pumps when used with included spring
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • Valve Aluminum
  • Seal PTFE
  • Spring
  • 4L60-E, 4L65-E, 4L70-E TCC Apply Valve Kit 77805E-K
  • 4L60-E, 4L65-E, 4L70-E TCC Apply Valve Kit 77805E-K
  • 4L60-E, 4L65-E, 4L70-E TCC Apply Valve Kit 77805E-K details