I just do a 4 qt drain and fill every 25-35K miles.

at 150K miles soon...so should be my 5th change or so??

 

I'm @ 500 miles now since the fluid change with the Valvoline. Had her out this weekend for a few spirited pulls in manual mode. Still no issues.

 

Have a used 2005 G35x. I'm unsure on the fluid change history, but it was owned by two Nissan dealerships for the first 70,000km, before a company purchased it and used it for another 100,000km over 5 years.

So I would like to assume everything was in decent shape for maintenance.

Am I safer assuming everything is kosher and leave it alone, or get it drained and re-filled?

 

Call up a dealership and see if you can get the service records for the car....if it was serviced at a dealership.

 

That's a perfectly valid point. I'll grab the history in my glove box and do just that.

Thanks.

 

How does it feel? Pure peace of mind says change it. If the color/smell of the fluid is OK, and it shifts smooth, I'd bet it was fine.

 

I still think it's a myth to the whole flushing transmissions causes it to go bad. I don't see how having old broken down fluid with gunk actually makes the transmission run perfectly fine, better than flushing out the gunk and old broken down fluid and replacing all with new fluid. This logically doesn't make sense to me, unless the transmission have previously unknown problems that just became more vivid because of the flush. Anyway, I purchased my 2008 g35xs last April with 43k miles and did a dealer transmission flush last week Saturday at 61k miles. I've been driving for a week, city and highway drive, automatic and ds mode, aggressive and non agressive and I have absolutely no problems with my transmission. Actually my transmission shifts even smoother than before, not that it was rough but now it's barely noticeable. Oh I also changed my transfer case fluid as well. Seeing that there was no problems at all flushing my transmission I'm going to flush it every 30k miles at the dealer, it only cost $302 for the flush, labor and fluids before tax. I'll change my differentials and transfer case every 15k miles. Again it's inexpensive and the car runs better than before.

 

Go buy a 200K F-150 with its transmission on its last legs for $500 and do a transmission flush. You will learn a lesson very quickly!!!!

 

From Wiki:

An old friend told me about this, he said back in the 50's and 60's you NEVER had to change your ATF.

 

Everything breaks down overtime, it's called normal wear and tear, and like I said, people who flush their transmission and have problems may be because the transmission already had a problem or problems unknown to the driver, or maybe it was flushed incorrectly. I have read somewhere in another thread that there are more than one methods to perform a transmission flush. Maybe it's the machine that does the flush on an old brittle transmission damages something, who knows. Transmission fluid does not last forever like any other fluid in your car and at some point you will need to change it out, whichever method you choose to do is up to you. I went to the infiniti dealer because I trust them to service components like this, my receipt said qty 12 of the matic s was used. I also don't believe in a drain and refill simply because when you mix new fluid with old fluid it becomes contaminated. You'd have to do a drain and refill, drive and then repeat maybe about 5 times to have most of the fluid in there pure, could be more. The point is though do not drive your transmission into the ground and then try to service it. Service it around every 30k miles and it would last longer. Just like you change your engine oil every 3k miles so your engine runs fine, treat your transmission good.

 

I was watching a video by EricTheCarGuy and I trust his opinion a lot. He did a video were he dismantles an automatic transmission. Basically, he says that overtime sometimes the clutch plates lose their friction material. This material will float around the fluid to help change gears. The fact it has thinner fluid and the clutch plate material could have been worn out causes the transmission to slip or gears not to work.

 

Which is my point, the transmission components has already started breaking down. Could be due to hard driving, over working the transmission, worn out fluid which deteriorates over time due to heat, or wear and tear like any other moving component, other factors like driving in and trying to force your way out of snow can have a play in a bad transmission or the oil burning. Changing the transmission fluid at earlier intervals will help protect the components from prematurely wearing. Engine oil breaks down much quicker which is why it starts turning black if you don't change it at a respectable time, that and dirt slowly gets in, plus it's a hard working component pounding out those combustion flames. I don't see anyone on here giving bad advice about not changing your engine oil because if their car runs fine no need to change it.