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  • Direct clutch burned
  • Gear ratio codes
  • No Reverse
  • 4th Slip
  • 3rd Slip
  • Reverse slip


Excess wear in Reverse checkball sleeve prevents proper application of direct clutches.


Restore hydraulic control and prevent premature wear by installing upgraded material Sonnax Reverse checkball sleeve.

4L80-E, 4L85-E

Reverse Checkball Sleeve
Part No. 34200-38

Fits units '95-later.

Package Quantity: 4

You need this if... View Instructions

Vehicles with '95-later GM 4L80-E and 4L85-E transmissions commonly exhibit wear in the Reverse checkball sleeve located in the 3-4 shift valve bore. This issue is caused by normal movement of the checkball within the sleeve over time. As wear progresses, sealing function of checkball becomes compromised and results in loss of apply pressure to direct clutches. Consequences of this pressure loss are slipping or no 3rd, 4th, and Reverse gears, burnt direct clutches, and ratio codes.

Installing Sonnax Reverse checkball sleeve 34200-38 restores the hydraulic integrity of this circuit to reestablish normal shift operation and performance.

  • Sleeve is manufactured from highly wear-resistant aluminum for maximum life
  • No reaming or special tools required

September 30, 2005

Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits

Gregg Nader

Topics: Diagnostics And Theory Transmission

Read Now
  • 34200 38 in combo
  • 34200 38

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg., or if wear is visually detected.

  • 34200 38 in test