Symptoms:

  • No engine braking in manual 2nd
  • Low line pressure in Reverse
  • Low line pressure in Neutral
  • Low line pressure in Drive
  • Delayed engagement

Cause:

Case bore wear and oil loss at the intermediate servo.

Correction:

Sonnax intermediate servo sleeve kit salvages the case, and eliminates the complaints caused by oil loss.

TH350, TH350C

Intermediate Servo Sleeve Kit
Part No. 35709-01K

View Instructions Find a Distributor

In GM TH350 and TH350C units, the intermediate servo bore becomes scored from repeated cycling. The spring side of the piston has line pressure present in R, N, D. Excess leakage at the servo piston results in low line pressure and delayed engagements. During forward speeds, oil loss affects shift quality and reduces clutch life. To salvage cases, install Sonnax intermediate servo sleeve kit 35709-01K.

  • Contains an aluminum sleeve and a replacement piston with a PTFE seal
  • Drop-in solution requires no machining of the transmission case
  • Sleeve
  • Servo Piston
  • Seal PTFE
  • TH350, TH350C Intermediate Servo Sleeve Kit 35709-01K
  • TH350, TH350C Intermediate Servo Sleeve Kit 35709-01K