Skip to content
Sonnax 34200-40K Smart-Tech Overrun Clutch Valve Kit For 1997-Up GM 4L80/4L85-E

Sonnax 34200-40K Smart-Tech Overrun Clutch Valve Kit For 1997-Up GM 4L80/4L85-E

by Sonnax
SKU S34741EQK
Sold out
$170.00 - $170.00
$170.00
$170.00 - $170.00
$170.00
Availability:
Out of stock

Delivery time

You will receive your package in 2–5 business days within the contiguous U.S.

Superseded Part Number: S34741ST, 34200-40K

Interchange Part Number: S34741ST, 34200-40K

Manufacturer Part Number: S34741ST, 34200-40K

Other Part Number: S34741ST, 34200-40K

Brand: Sonnax

Manufacturer Warranty: Yes

Sonnax Smart-Tech® Overrun Clutch Valve Kit

Part No. 34200-40K

Fits units '97-later

Insufficient holding power in the overdrive roller clutch is the underlying cause of chronic overdrive roller clutch failure in hardworking 4L80-E and 4L85-E transmissions. When the roller clutch fails, the damage can be catastrophic and the only fix is replacing the drum, planetary assembly and mating components.

The Sonnax Smart-Tech overrun clutch valve kit 34200-40K offers a hydraulic solution to this known mechanical problem. With unique rerouting of hydraulic fluid pressure, this patented kit keeps the overrun clutch applied at all times (except OD 4th), reinforcing the roller clutch to adequately support heavy loads.

  • Improves OD roller clutch holding power in D4 and Reverse ranges
  • Extends the life of workhorse transmissions while preventing warranty claims and comebacks
  • Installs quickly onto the valve body — no transmission removal needed
Range Gear Overrun Clutch with
Sonnax 34200-40K
Clutch Valve Kit		 Overrun Clutch
with OE
Clutch Valve
Park
Applied
Reverse
Applied
Neutral
Applied
Overdrive 1st Applied
2nd Applied
3rd Applied
4th

Drive 1st Applied Applied
2nd Applied Applied
3rd Applied Applied
D2 1st Applied Applied
2nd Applied Applied
D1 1st Applied Applied

Any other modifications to the valve body should be completed prior to installing Sonnax Smart-Tech® overrun clutch valve kit.

  • Socket-Head Cap Screw Long
  • Socket-Head Cap Screws (2) Short
  • Button-Head Screws (2)
  • Retaining Pins (2)
  • Valve Manifold
  • Short Tube
  • Long Tube
  • S-Shaped Bracket
  • Flat Bracket
  • L-Shaped Bracket
  • Gasket
  • End Plug
  • Valve
  • Spring
  • Sleeve
  • Tabbed Bore Plug
  • O-Rings (3) 1 Extra
  • Cap Plugs (2)
  • Aluminum Plugs (2) Small, 1 Extra
  • Alignment Pins (2)
  • Drill Jig
  • Drill Bit Small (.109" dia. )
  • Drill Bit Large (.180" dia.)

Use this text to share information about your product.

Blog posts

See more