HOXXOH

IIRC, since it's been awhile, the stock rev limiter is set at 6600 RPM and the 1-2 shift comes at 6500 RPM in S and 6300 RPM in D. Apparently something in your tune has been changed. It's also possible, but less likely, that a low fluid condition can cause the same result, especially if the trans fluid is too cool.

Vette_Fan

I haven't gone FULL WOT yet, but it seems perfectly logical - if you step on the gas and go all the way, you should be hitting Redline before shifting to next gear (at least in the 1st gear).

Vette_Fan

That is good (new) news to me My 08 does the same thing. Once in "S" mode and paddle shifting, in order to get back to regular "auto" mode, I have to shift it into "D". Besides, I don't see a difference in D or S, except in S it smees to shift more seamlessly (as automatics are supposed to).

Vette_Fan

Has anyone . . . (drum roll)....




Gotten their A6 flushed & filter changed? If yes, what are your observations/experience?

Stats

From my research and personal experience, I would NOT flush an automatic transmission. Apparently, (yes, personal experience on another vehicle) it can loosen "contamination" that was not a problem and it can lodge in another part of the transmission and cause problems OR the transmission can become accustomed to the positioning of this contamination and operate oddly when it is removed.

Changing the fluid and filter is a great idea, but I will never flush a transmission again unless I was desparate.

HOXXOH

There's two ways to look at the possible result. If you add the cooler prior to the radiator, it will cool the fluid and then heat it to the coolant temperature if it's too cool. That would be the more likely result during the Winter. If you add the cooler after the radiator, it will cool the fluid cooler than the coolant. That's more likely during the Summer.
The concern in making the decision is whether you want the fluid temperature below or equal to the coolant temperature. For longevity, 175 is ideal, below 160 creates shifting problems, above 190 reduces longevity, above 230 starts damage, and above 260 is destructive. Of course, those temperature concerns are for long term continuous use, not just the occasional brief periods like stuck in heavy traffic. The assumption is also that you don't go WOT before the fluid is 160.
Another way to look at this, is to do nothing as long as you keep the coolant below ~200. That means your trans fluid will also be below ~200 too. However, once the trans fluid gets hotter than the coolant, it takes a lot longer to cool back down than the coolant, since the radiator's primary job is too cool the engine. Driving across the desert at reasonable speeds won't create as much heat as stop and go rush hour traffic, because there is good air flow for the coolant and the trans creates very little heat when the converter clutch is locked. If you play in mountain passes, use the paddles to keep the converter locked too. This is especially important if you have a high stall converter.

HOXXOH

Pull the pan, change the filter, and refill only. Don't flush.
Don't bother changing fluid under normal conditions for 100K miles or under severe use for 50K miles.
If/when you do change it, make sure you follow the correct method to the letter for a stock converter. Rules are slightly different for high stall converters.
BTW, if you don't do your own work, at least learn the method and ask the mechanic (not the service mgr) to tell you how he plans to do it. If he gives you one wrong answer, find a different place. A screwup here can be expensive.

vezePilot

This is a great thread. Thanks to all those contributing.
I went up for a little "spirited" driving in "mountain passes" just in order to document temps after starting to read, and before finishing, this thread.
Outside Air Temp between 80 and 90 (once out of town); Oil Temp peaked at 220, Coolant Temp at 201, Trans Temp at 210. Using paddle shifters, in a totally stock 2007 Base 3LT A6.
I am also planning on having a very reputable Corvette-only shop apply some tunes to this car, but not right away and only after some research ... in threads like this one.

Cockroach

[QUOTE=farmington;1597635457]
I have a Diablo sport tune loaded, I did call them about this issue and they said not normal. They recommended a new download tune that from what I understand is an updated version with some improvements in the tune. FYI with the oem tune this didn't happen. BTW stock converter. Raining here in the Chicago area so no chance yet to try the new tune.

SwissC7

Vette_Fan

Well, I have about 35K miles. And since I am a bit particular about my Vette (like many owners), I don't care to spend a bit more money and don't want to wait for the "recommended mileage" service, which is at 50K. So I got the tranny flush FLUSH & filter at Abel Chevrolet, a well-known dealer and sponsor here on CF. Their advice was that it's Okay to flush it out, especially if you have low miles. AND they use a system most others don't - they use the car's internal pump to pump out the old fluid, while mixing the new fluid into it. 12 quarts total. My next flush will be at 60K miles - I intend to do it every 30K miles are so. That way we don't have to worry about the broken particles floating in there for too long.

Vette_Fan

Good Info - So if 175* is ideal - the car NEVER runs at that for too long. It always climbs up to 199 (same as coolant), sometimes up to 210. And you're saying over 190 reduces longevity. I think to get the BEST of BOTH WORLDS - get the smaller cooler (14,000 BTU), which I had on my C5, and install it "after" the radiator, in series. It should keep temps 180 - 190. Or just screw it, and get the 20,000 BTU cooler and maintain 175-180*. I am certain it's never gonna be too cool.

I've read about using paddle shifting to keep it "cool", because.....(whatever the reasons are). Anyhow, I've tried it, it won't lower the temps.

Vette_Fan

First, thanks for the compliment to all those who are contributing to the thread - this is why I thought it was a good idea.

Secondly, Asking questions is a way of contributing also. And getting answers obviously is.

The Temps you've mentioned seem about normal to me, my car runs about the same. I too will get a Tune, but waiting to add some mods...then.

Stats

HOXXOH

When you pick parts of information to digest, rather than the whole picture, you lose understanding of the functions. GM cycles the fluid through the radiator in an attempt to control the temperature in a workable range. While not the most ideal range, it's one that works best regardless of ambient temperatures. Due to EPA regulations, your coolant is controlled by a 186* t-stat, so that forces the trans fluid out of the ideal range.

Because the system for cooling the trans fluid is only a partial flow, it can't be directly controlled with a t-stat. You also can't "flush" the 13.25 quart system with 12 quarts of fluid either.

If you want to lower the average trans fluid temps, then start by first lowering the engine coolant temps. A 160* t-stat can keep coolant in the 170-180 range and the trans fluid about 5 degrees warmer. Of course, those temps are for normal driving and don't apply if you're stuck in b2b rush hour traffic and/or in hot ambient conditions.

Don't kid yourself into believing you can't get the trans fluid too cool. You can cause damage that way just as easy as too hot.

I don't remember what gears or speeds are on a stock tune to lock up the converter clutch, but what I can say is you can control the lock up far better in paddle mode. Lock up won't cool the fluid, but it can avoid it getting hotter. The converter is what creates the majority of the heat, so anytime it's locked helps.

449er

A tune is what you need to change your shift firmness on the paddles especially, gone are the days of adding a "shift kit"

Cockroach

Update... I installed a new tune from Diablo and now it seems to be shifting correctly. 1st to 2nd will now shift in S mode at 6500 rpm and when using the paddles the shifts seem to have less lag. Thanks to all for their input.

Iceman007

Do yall know if you install a tune with this void an extended warranty?

Cockroach

No extended warranty, no worries. Tunes can be pulled and the oem re installed in minutes with no trace.

farmington