• Burnt clutches
  • Delayed engagement
  • 3-4 Bump
  • Inadequate lubrication
  • Low pressure
  • Slips & flares
  • Soft shifts
  • TCC apply & release concerns
  • TCC codes


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.

6L45, 6L50, 6L80, 6L90

Zip Kit®
Part No. 6L45-6L90-ZIP

View Instructions Find a Distributor

Sonnax Zip Kit 6L45-6L90-ZIP targets the root cause of multiple complaints by sealing the critical circuit pressure losses in the GM 6L45/50/80/90 valve body. The kit contains uniquely designed parts to prevent the loss of pressures within the main line, clutch apply control, solenoid feed and lockup control circuits. The kit also seals multiple circuits known to suffer from end plug leakage or poor checkball sealing. 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 valve body 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
  • Pressure Regulator Valve Kit
  • Boost Valve & Sleeve
  • Clutch Select Valve Spring Kit
  • Compensator Valve, Sleeve & Spring
  • TCC Regulator Valve Kit
  • O-Ringed End Plugs
  • Actuator Feed Limit Valve Kit
  • Center Support Seal Kit
  • Vacuum Test Nut
  • Checkballs (8) .250" dia.

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 6L45, 6L50, 6L80, 6L90 Valve Body Layout

GM 6L45, 6L50, 6L80, 6L90 Valve Body Layout
  • 6L45, 6L50, 6L80, 6L90 Zip Kit® 6L45-6L90-ZIP


GM 6L80 Series Transmission Upgrades & Repairs
6L80 Series Pump Drilling Demo with Small Drill Bit Vise
Zip Kit® Video - The First Step in Correcting Common Shift Problems
6L80 Series Pressure Regulator Valve Repairs: Pump Drilling Explained
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