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:
Sonnax drop-in modulator sleeve restores hydraulic clearances to prevent shift issues.TH180, TH180C (3L30)
Modulator Sleeve
Part No. 41820-08
You need this if...
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The cast aluminum modulator valve sleeve in the GM TH180 and TH180C (3L30) cases are 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. Excess 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
- Drop-in Zip Valve™ installs quickly and easily
Designed for valves with a small spool O.D. of .335" and large spool O.D. of .367". Verify OE valve dimensions before install.
You need this if...
Visual wear is detected on the inner and outer diameters of the sleeve.