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Old 12-11-2011, 01:14 PM   #78 (permalink)
wstar
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Quote:
Originally Posted by brucelidat View Post
Are you saying to get a cooler for the transmission? I am going to a track day next weekend and no one has mentioned a cooler for the tranny. How important is this? Also, I thought the tranny was sealed. How do you change the fluid?
You *can* do a track day without an AT cooler, esp if it's one of your first. Just be cognizant of not overheating it too much. If you're only doing 10-15 minute sessions of balls-out driving and getting some cooldown in-between, it will probably ok, especially in winter weather. You'll know it when it starts getting too hot. It will start performing crappier (slower shifts, etc), you'll feel it.

As far as fluid changes go: from a factory service manual perspective, it's supposed to be "maintenance-free" for the consumer. So they don't provide a dipstick for checking the level, or any sort of easy filler tube either. There are procedures for checking fluid level and draining/filling, but the draining and filling is done via drain-fill plugs on the transmission body itself (much like with a manual or a differential).

The correct fill level, as with most things of this nature, is when it barely seeps out of the fill hole. However, to get the factory-correct fill amount, you have to check this with the internal temperature of the 7AT in a very specific range. The TCM knows this temperature, but only Dealership tools can read the temperature to know the fill is correct. That's the reason that, generally speaking, only the Dealership can deal with fluid checks/changes.

In practice, you should probably get the fluid swapped every ~20K miles for a hard-driven and/or lightly-tracked car, IMHO. The easiest and most reliable way to do it at this time is to have a dealership do it for you. Just make sure they don't just send some random tech to do a "standard" transmission flush. Be sure they've read the 370Z service manual and understand about the filling procedures and checking Consult-III temps, otherwise they're doing no better guesswork than you could in your garage.

Supposedly GTM was working out a set of instructions for us to reliably refill without a dealership. They probably developed a guideline based on spot-checking some point on the transmission's outer case with an IR thermometer. Never heard any more details on this though.
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