Symptoms:

  • Flare downshifts
  • Late upshifts
  • Soft shifts
  • Erratic shift timing
  • Low line rise
  • Stacked shifts

Cause:

Wear at the cast aluminum modulator valve sleeve allows leakage of line, modulator and governor pressures.

Correction:

The Sonnax sleeve restores hydraulic clearances to prevent shift issues.

180, 180C (3L30)

Modulator Sleeve
Part No. 41820-08

You need this if... View Instructions Find a Distributor

The cast aluminum modulator valve sleeve in the GM 180, 180C case is known to wear due to continuous stroking of the steel valve. This valve regulates line pressure into modulator pressure and is also controlled by governor pressure. Excessive sleeve wear can result in leakage of line, modulator and governor pressures, leading to a multitude of shift complaints and poor line rise. Sonnax modulator sleeve 41820-08 corrects these issues by restoring hydraulic clearances.

  • Upgraded material resists wear
  • 180, 180C (3L30) Modulator Sleeve 41820-08
  • 180, 180C (3L30) Modulator Sleeve 41820-08

You need this if...

Visual wear is detected on the inner and outer diameters of the sleeve.