Hi all - I have an '06 C6 base. I usually take it easy until the car's coolant temp gets up to 190 degrees give or take. However, sometimes, the car will have a rough shift between gears, especially during warm up. It will drop a gear for a second or two, then upshift, then upshift again. This is when revving normally, nothing spirited at all. Very uneven feeling. Most of that goes away once the tranny fluid gets up to running temps, but recently, it will act up a bit between 2 and 3. It will down shift for a second or two, and then go into 3 and sometimes quickly into 4. Car has 85k. I topped off the tranny fluid over the summer, but didn't seem to impact it too much.

Is this normal? Not sure when the fluid was last changed. I have had the car a year, and it does have a tune, which I know can impact these things. Wondering if a fluid change will address this or if there is something bigger I should be checking on? Also, I do have an extended warranty for another year, so I was thinking about bringing it in to a shop since the drive train is covered.

Would appreciate your thoughts/suggestions.

Jon

 

Very possible the fluid and filter have never been changed. I would do that first and then see how the transmission performs. Simplest, quickest thing to do.

It is quite amazing how some transmissions will feel like they are on the verge of failing and all they need is a fluid change.

 

There is no "topping off" of fluid on the A6 trans. If you added fluid without going through the process to drain off the excess, that's likely the majority of your problems.
See these two threads for more info.
https://www.corvetteforum.com/forums...tructions.html

fill plug tool
https://www.corvetteforum.com/forums...uid-plugs.html

 

thank you! I did add after checking the level while running, and then drain the excess properly. Waited till the dripping basically stopped.

 

I assume you were still below 122 F when you replaced the plug, otherwise your fluid level is lower than intended. I always start the excess drain at 100 F and stop it at 104 F to ensure mid-range and consistency. Also make sure the car is level when draining excess. A 2 foot level on the doorsill works great. Just don't expect your garage floor to be level, since they are sloped for drainage.

Since the trans is volume sensitive and the fluid expansion rate is on the high side, fluid temps below ~ 160 F cause inconsistent shift points that are most noticeable at WOT.

Do you know if the torque converter is OEM or aftermarket? As a general rule, people tend to overfill a high stall converter by 1/2 to 1 quart to ensure enough fluid is there to keep from nosing over on the launch. A scan will show a slight dip vs a constant increase.

If it were mine, I'd add a half quart to see if it made a difference and another half quart if it got better, but still with some slight shifting issues. You don't get into overfill problems until 1.5 to 2 quarts.

One last thing to remember. The whole system holds 13.25 quarts and a pan drop only drains about 6.5 quarts, meaning you only change 1/2 of the fluid at a time. GM spent millions to test and initially develop the A6 trans while working together with Mobil Oil who created the best fluid for performance and longevity of that specific transmission. The bottom line is that no other fluid manufacturer has spent the time and money for testing to develop a product that is any better. So other than price or advertising claims, why would anyone think that a 50% mix of some other fluid would make their transmission be magically superior?

 

Thanks, HOXXXOH - great post. I will recheck with your post in mind! Fluid last time was still reddish, no burnt smell at all. Good info above.....thanks again.