I should add that when I had the service, my tranny was behaving badly, and the full service restored it like new.
Yes definitely pay the money for a "full transmission service" which would be to drop the pan, complete drain, change filter and seals, proper refill with correct fluid (Dexron VI),
and Fast TAP Relearn.
IMO the filling procedure is quite difficult to get right due to access and timing, as the fluid needs to be between 30º and 50º which is actually a small window, even smaller in summer. It can take hours to cool enough to be within range again.
The six speed utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components and to maintain shift quality. (Without this control system shifts would be more abrupt and harsh). By adjusting the line pressure, the TCM (transmission control module) can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" to modify the Transmission Adaptive Pressure (TAP).
Holden is able to initiate maintenance cleaning of solenoids and update TAP information by hooking into the TCM to re-establish acceptable shift times. It is a simple software routine however it may take up to three hours and hardly anyone does it AFAIK. What doesn't help is that technicians are advised by GM that it is not recommended for TAP information be reset unless one of the following repairs has been made:
- Transmission overhaul or replacement
- Repair or replacement of an apply or release component, clutch, band, piston, servo
- Repair or replacement of a component or assembly which directly affects line pressure
I have had quotes from $126 to $290 to do this, (and can be performed with EFILive tuning software) but once reset, driving normally (conservatively) for a tank will set a baseline such that it will feel like a new tranny. Else it will still be stuffed because of a mechanical problem!