Skip to content

Modified Item: No

Country/Region of Manufacture: United States

Custom Bundle: No

Core Charge: No

Bundle Listing: Yes

Placement on Vehicle: Front

OE Spec or Performance/Custom: OE Spec

Surface Finish: Brand new

Manufacturer Part Number: 6T40-ZIP

Other Part Number: S46741A-ZK

Brand: Sonnax

Fitment Type: Performance/Custom

Non-Domestic Product: No

Drive Type: 4WD,AWD,FWD

Manufacturer Warranty: Yes

6T40 - 6T45 - 6T50 Transmission Valve Body Kit

Sonnax 6T40-ZIP


Fits GEN 1 units ONLY - Review 2nd photo above for how to ID your Unit

Symptoms: Burnt clutches  -  Line pressure instability - Loss of fuel economy - No line rise - Pressure loss -
Pressure switch codes - Shift concerns - TCC apply & release concerns - TCC codes

Cause: Loss of oil pressure due to worn components in critical circuits and/or pressure switch failure.

Correction: Recover hydraulic control, restore normal shift operation and save the transmission control unit by installing Sonnax Zip Kit.

Sonnax Zip Kit 6T40-ZIP targets the root cause of multiple concerns by sealing critical circuit pressure losses in first generation GM 6T40, 6T45 and 6T50 valve bodies. The kit contains uniquely-designed parts to prevent the loss of pressures within the main line, clutch apply control, actuator feed, compensator feed and lockup control circuits. The kit also seals multiple circuits known to suffer from end plug leakage or poor checkball sealing. No separate special tools are required for installing these parts.

Replacement pressure switch seals and laminate discs in this Zip Kit address various trouble codes related to failures of fluid pressure switches which are internal to the transmission electro-hydraulic control module (TEHCM).

The Zip Kit quick guide provides clear and easy instructions on one sheet to get the unit sealed up and back on the road quickly. 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.

  • No reaming required
  • Installs quickly with no separate special tools required
  • Uniquely designed parts address root causes of valve body concerns by sealing critical pressure circuits
  • Detailed technical booklet included with in-depth rebuild and inspection tips for comprehensive valve body repair
  • Allows salvage of expensive TEHCM
  • Pressure Switch Rebuild Kit
  • Compensator Feed Regulator Valve Kit
  • TCC Regulator Apply Valve, Shuttle Valve, End Plug, Spring & O-rings 2 O-Rings, 1 Extra
  • AFL Valve, Sleeve, Spring & Retainer
  • End Plugs (5)
  • O-Rings (7) 2 Extra
  • Checkballs (6) .250" Dia.
  • Drill Bit .062" Dia. (not shown)
  • Aluminum Plugs (2) .062" Dia., 1 Extra (not shown)

All of our items listed are in stock and ready to ship 

We Quick-Ship Every Day !

Use this text to share information about your product.

Blog posts