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

Downshift Speed Test

To carry out this test, proceed as follows:
^ Shift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
^ Drive at the engine rpm where the concern occurs.
^ The concern is engine speed-related if duplicated while carrying out this test. This eliminates the tires, wheels, brakes and the suspension components as sources.
^ If necessary, repeat this test using other gears and NEUTRAL to verify the results.
^ Proceed as necessary.