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Sonnax

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Transmission

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Symptoms:
  • 1-2 Harsh
  • 3-4 Clutch burnt
  • Code 1870
  • Low line pressure
  • Low TCC apply pressure
  • Overheated converter
Cause:

Excess wear at TCC regulator/isolator valve bore allows TCC apply pressure to exhaust.

Correction:

Recover hydraulic control and renew TCC performance by reconditioning the bore and installing Sonnax TCC regulator and isolator valve kit.

Tool Required Icon VB-FIX Required Icon

TCC Regulator & Isolator Valve Kit

Part No.

77754-04K

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

  • 77754-04k_combo

  • TCC Regulator & Isolator Valve Kit

Small_77754-04k_combo Small_77754-04k__1_
Tool Required Icon VB-FIX Required Icon

TCC Regulator & Isolator Valve Kit

Part No.

77754-04K

  • Isolator Valve
  • Spring
  • Regulator Valve
  • Regulator Sleeve

Any application, including '98-later EC3 units

Complaint:

  • 1-2 Harsh
  • 3-4 Clutch burnt
  • Code 1870
  • Low line pressure
  • Low TCC apply pressure
  • Overheated converter

Cause:

Excess wear at TCC regulator/isolator valve bore allows TCC apply pressure to exhaust.


Correction:

Recover hydraulic control and renew TCC performance by reconditioning the bore and installing Sonnax TCC regulator and isolator valve kit.

Severe wear of the TCC regulator valve bore caused by oscillation of the OE valve allows regulated converter apply pressure to exhaust. This is a primary cause for TCC-related slip code P1870 and overheated converters. Exhausting apply pressure also diminishes line pressure, which can result in burnt clutches. Excess wear at the isolator valve bore reduces TCC apply pressure. Reconditioning the bore and installing Sonnax TCC regulator and isolator valve kit 77754-04K restores normal TCC operation by shoring up the hydraulic integrity of this circuit.

  • Sleeve manufactured from highly wear-resistant aluminum
  • Hardcoat anodized aluminum regulator valve combats premature wear
  • Isolator valve lengthened to operate in unworn portions of the bore
  • Annular grooves help center valves in bore to reduce future side-load wear
  • Patent No. 6,990,966
  • Patent No. 7,104,273

You need this if...

See the Part Selection and Reaming Options Instruction sheet to determine which combined Sonnax parts and tool kits will repair your GM 4L60-E PWM and Non-PWM valve body

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Sonnax

January, 2013

GM 4L60-E Vacuum Test Guide

Contact a Sonnax Distributor to purchase this part.