Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Shift Modulator: Service and Repair


1. Raise and support vehicle.
2. Remove vacuum line from modulator.
3. Using vacuum modulator wrench J-23100 remove modulator, seal and modulator plunger.
4. Then remove modulator valve and sleeve.
5. Clean all parts with soapy water and air dry.
6. Check modulator and vacuum line for kinks, cracks and dry rot damage.
7. Reverse procedure to install using new seal. Add transmission fluid as necessary.