Quote:
Originally Posted by MazdaMatt
Typically under normal acceleration, it shifts around 3krpm and under normal on-throttle deceleration it will downshift around 2krpm (i think). It is REALLY frustrating to be sitting at 62km/h at 2900rpm (ish) and the damn thing isn't shifting. Redline is about 3200rpm.
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The more I think about it, those shift rpms sound reasonable for a gasser, but entirely too near high end of scale for a diesel (more torque at lower rpms). I wonder if all oem C6's have the same valve body. Any chance some previous owner changed out the transmission? eg C6 tuned for diesel came out and was replaced with new/used/rebuilt C6 intended for gasoline engine? (Not even certain that's a valid question to ask.)
Before you talk to a/the transmission mechanic, crawl under and look for vacuum hose or electric wires leading to a shift modulator on the transmission. Could be a $20-$40 part may help the delayed shift problem.
If it's a vacuum modulator, check for a leaking vacuum diaphragm. If it's electric, look for frayed/broken wires. Consult manual for how to test.
While you're under there, write down the info off the tag on the rear-end. The transmission specialist might want to know what size tires & wheels - write that down too.
What does the transmission fluid look and smell like?
Any idea when or if the transmission fluid and filter were last changed?
Hope this helps.