• TCC apply & release concerns
  • Overheated transmission & converter
  • Loss of cooler flow
  • Loss of lube oil
  • Burnt converter
  • High TCC slip RPM
  • Code P0218
  • Code P0741


Loss of oil pressure due to worn components in critical oil circuits.


Zip Kit seals critical pressure losses. Drop-in parts install quickly and easily.

8L45, 8L90

TCC Zip Kit®
Part No. 8L45-8L90-TCC-ZIP

For converter-related complaints.

View Instructions Find a Distributor

Sonnax TCC Zip Kit 8L45-8L90-TCC-ZIP targets the root cause of multiple converter-related complaints by sealing the critical circuit pressure losses in the GM 8L45 and 8L90 valve body. The kit contains uniquely designed parts to prevent the loss of pressures within the lube, converter limit, line pressure and converter apply circuits. These solutions target wear that results in lube-, cooler- and converter-related complaints. No special tools are required for installing these parts.

The Zip Kit quick guide provides clear and easy instructions on one sheet to get the unit sealed up and back on the road fast. In addition to general rebuilding tips and technical information, the technical booklet included in this kit contains vacuum testing information and locations at other key areas of the valve body.

  • Drop-in Zip Valve parts install quickly and easily, no reaming or special tools required
  • Uniquely designed parts address root causes of converter and lube related complaints by sealing critical pressure circuits
  • Detailed technical booklet included with in-depth rebuild and inspection tips for comprehensive valve body repair
Learn More About Zip Valve™ Drop-In Repairs
  • O-Ringed End Plug Kit
  • Converter Feed Limit Valve Kit
  • Pressure Regulator & Shuttle Valve Kit
  • TCC Clutch Control Valve, Seal & Spring

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

GM 8L45, 8L90 Valve Body Layout

GM 8L45, 8L90 Valve Body Layout
  • 8L45, 8L90 TCC Zip Kit® 8L45-8L90-TCC-ZIP
Sonnax Zip Kit

The Sonnax ZIP KIT®

The First Step in Correcting Common Shift Problems

It's easy to restore and extend vehicle shift quality with Zip Kits. Uniquely designed, drop-in Sonnax parts target the root cause of valve body complaints and stop critical circuit pressure losses in the most common problem areas of the transmission.

Learn More About Sonnax Zip Kits