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Fixing hard shifts with the missing PROXI

by David Zatz on

Some readers have reported rough shifting after work was done on their car. This may not be a bad transmission, but a missed step in the repair: skipping the “PROXI alignment,” which updates information in all the car’s systems.

Matthew Libanio, for example, had his TCM (transmission control module) updated; the dealership did a “quick learn,” but failed to do the PROXI alignment, apparently through confusion, resulting in poor shifting.

transmission controller computer (electronics)

PROXI integrates the car’s many computers, from navigation to the transmission. One technician wrote, “PROXI alignment is required when a module is replaced, or, in this case, the transmission bangs into gear something fierce. It does make a big difference.” One telltale (though it may not always appear) is a blinking odometer.

An FCA spokesman wrote, “It’s called out in the service instructions. Skipping the procedure is not an option. We encourage customers to contact the company directly if they have concerns, at 1-877-IAM-JEEP (426-5337); 1-888-CIAO-FIAT (242-6342); or 1-800-CHRYSLER (247-9753).”

Dealership have a great deal of data on how to repair cars, but sometimes a rule is skipped by mistake or, in the case of independent garages and DIY repair, because people are unaware it’s needed or don’t have the right tool. However, this is a key step which can be mistaken for a bad transmission, especially as these cars age.

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