External Diagnostic Tests

The St. Marys AAMCO External Diagnostic Service is a systematic and comprehensive external evaluation of the overall performance and condition of your transmission.

• A trained mechanic will check the level and condition of your transmission fluid:
• A low fluid level may indicate a leak.
• Contaminated fluid has water or particles in the fluid.
• Burnt fluid indicates damage from overheating.
• Varnished fluid has been overheated repeatedly.
• Normal fluid is reddish-brown and translucent, depending on transmission type, with no odor.
• The mechanic will also check the level and condition of transfer case and differential fluid, where applicable.
• The mechanic takes your automobile on a road test, to experience first-hand any problems you have noticed, and to evaluate your automobile's performance.
• Your automobile will be placed on a lift to inspect the controls under the automobile for any possible cause of the problem external to the transmission.
• Finally, the mechanic will scan the computer for trouble codes.