Skip to content
Sonnax 34200-03K Transmission Boost Valve & Sleeve Kit (Factory Style) 4L80E

Sonnax 34200-03K Transmission Boost Valve & Sleeve Kit (Factory Style) 4L80E

by Sonnax
SKU S34507ERK
$19.21 - $19.21
$19.21
$19.21 - $19.21
$19.21
Availability:
in stock, ready to be shipped

Delivery time

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

Brand: Sonnax

Other Part Number: S34507RBK

Type: Line Pressure Booster

Interchange Part Number: S34507ERK

Items Included: Boost Valve Kit

Manufacturer Part Number: 34200-03K

Universal Fitment: Yes

Vintage Part: No

Performance Part: Yes

4L80-E, 4L85-E Transmission

Boost Valve Kit
Part No. 34200-03K

Fits '91-later units with factory-style sleeve, no O-rings. Can be retrofitted to '89–91 units. See instructions for details.

Common problems in vehicles with GM 4L80-E and 4L85-E transmissions are uncontrollable line rise (upward of 500-600 psi), high line pressure in Reverse, buzzing noise, broken direct clutch drums and/or broken cases. These problems are usually caused by Reverse boost oil that enters the torque signal circuit due to a wear-created cross leak at the sleeve. High line pressure and buzz is created by oil leakage past the aluminum balance plug. Sonnax boost vavle kit 34200-03K eliminates these problems.
  • Hardened steel boost valve with over 20% wider spools to provide better durability and increased sealing contact area
  • Boost valve spools have annular grooves to reduce side-loading that causes wear
  • Valve and sleeve are manufactured to close tolerances to restore proper clearance and hydraulic integrity
  • Kit includes a replacement aluminum balance oil plug with an O-ring to ensure proper sealing and adequate back pressure on the pressure regulator valve

If you detect leakage between the sleeve and pump bore, use 34200-01K, which includes an O-ringed sleeve to compensate for pump bore wear and prevent pump scrappage.

  • Valve
  • Sleeve
  • Balance Plug With O-Ring

Use this text to share information about your product.

Blog posts

See more