Hello, I know this question has been asked a few times but I�m having a bit of trouble deciding. I have a 2006 Infiniti G35x with 91,000 miles on it. I�m not sure if the transmission fluid has ever been changed. I looked at it and it wasn�t very dark or burnt, it had a reddish-brown tint. I called my local Infiniti dealer and they said a flush would be fine with only 91k, they don�t recommend flushes after like 150k. I�ve read multiple different opinions and was going to do a drain and fill but the dealer told me they don�t do that. I suppose I could try a local shop for a drain and fill, just looking for some opinions here on which is safer and better. He also quoted me $250 for the flush, not sure how bad of a price that would be. Thank you for the help!

 

I changed my 05' G35x at 156k miles and it looked like original Nissan fluid but darker. Probably was never changed. The Nissan/Infiniti fluid is a brownish color unlike Dextron mercron fluids. I have been using Dextron Mecron in the G35 and my RE4 G20 autos for quite a few years without problems. I haven't ever taken mine to get changed so I don't know what a good price is. DIY price: 2 gallons of ATF $18 per gallon plus 1 transmission filter $10.

 

That they would even think of charging you $250 for 4 quarts of fluid and 20 minutes of their time is absolute highway robbery. I don't know how they get away with that kind of bullshit.

As for not recommending you the transmission fluid changes after a certain mileage? WTF! Drain/fill the thing every 30k miles or you will experience unnecessary wear on internal components. Every fluid in the vehicle has a maintenance schedule, do it yourself and save a lot of munney and the vehicle will last you a very long time without random stuff failing from lack of maintenance.

 

Well it was $250 for the flush which is over 10 quarts. I�m only at 91k so he told me to change it and that a flush would be ok. I�m not sure if that�s safe or if I should do a drain and fill because I don�t think the fluid has been changed yet....

 

The worst part about a tranny fluid change is that you can not get all of the fluid out of the converter. The converter itself probably holds 2 quarts. When I changed mine I used about 7 quarts of ATF. So quite a bit of the old fluid will get mixed with the new.

 

So would you suggest doing a few quarts (drain and fill) or the full flush? I�ve read things and worry that a full flush for the first time at 91k could be damaging.

 

My 04 had a flush at 30k. I just did a drain and fill at 80k. Plan on doing a drain and fill again this weekend at 87k. If you are concerned do a drain and fill every oil change until the fluid looks new. A bigger concern to me is a radiator failure which allows coolant to enter the transmission and kill it. An external transmission cooler is next for me.You will be pleasantly surprised how much of a difference a drain and fill makes. Definitely smoother operation.

 

The only thing you have to worry about with transmission fluid is condensation, contamination (clutch material), and heat (breaking down of the fluid which has to be really really hot). It's not like engine oil that gets a lot more contamination over time. The only thing you are doing with a full drain and fill @ 91k miles is removing contaminated fluid (nothing dangerous about that) that may have condensation from heat cycling (mostly boils out at high temps anyway) and clutch material from normal wear. If you change your trans fluid yourself make sure to clean the magnets in the pan really good. When they get caked up they don't catch the material anymore and that's when your fluid really gets bad. It starts to get abrasive and eats seals, clogs the valve body internal mini filters and all sorts of fun stuff.

Honestly if I was planning to get 200k+ out of one of these transmissions I would change the fluid every 50k and put a shift kit in it. The shift kit will take out the glide and the clutches will last wayyyyy longer. The first time I let my 04' with 125k miles shift at redline it made me cringe because I have never felt any transmission take that much time to shift. The shift kit doesn't make it jerky or feel race only and should have felt like that from the factory being a performance sedan. Of course if you drive it like grandpa the shift kit won't help much and fluid / filter changes are all that is really needed if you drive like a normal person

 

I've actually been debating this lately. I bought my 07 with 150k on it and the fluid looks dirty and I've been debating on whether I want to change it or not. I just changed the fluid on my parents 2010 tsx and the car shifts like it should. My car shifts as it should as well, it hunts a bit sometimes but I'm planning on a full tune up and throttle body cleaning as well. So the question is, is it a good idea to drain and refill at 156k? Sorry to thread jack op, didn't want to make an entire new post about an topic that has been covered before lol

 

No worries man lol I�m wondering the same thing. Not sure if it�s safe to do a full drain of all the quarts even at my mileage. There are lots of myths and disagreements over when to do tranny changes and when to leave it alone. I want it to last a while and shift well so I�m doing a drain and fill (4-5 quarts) at the very least.... just looking for some opinions on which to do.

 

So do you think a full flush would be safe if the fluid has been in there for 91k miles? I just don�t want any problems with the transmission afterwards. Not sure if the drain and fill of a few quarts is safer or not

 

Having read a lot of threads here, the safe route to go is drain and fill. While the stories are anecdotal and not statistical, there are numerous reports of severe problems after flushing higher mileage 5ATs, and none that I have seen for drain and fill.

 

Power flushing is never recommended on an automatic transmission for any reason, ever.

I don't even know why the machine was invented.

I also have no idea why a Nissan service tech would recommend getting one. If you're behind on transmission service then just do a few consecutive drain/fill with the next few oil changes until you are caught back up again.

 

I remember when I was a kid everyone said never change your fluid if the transmission has over 100k+ miles and has never been serviced. I always listened to that until I started rebuilding them. Dirty fluid, clogged filters, and a caked up magnet won't keep you transmission going. If a transmission fails after a fluid change it would have failed the same way without a fluid change. A transmission's lifespan equation, cleaner fluid = less wear = longer life. Equation backwards Dirty fluid = more wear = less life. All the automatic transmission is a hydraulic system and gear box. The cleaner you keep it the longer it will last.

They are starting to make improvements on some of the newer transmissions with external filters that can be changed just like oil filters. I haven't ever cut one of those filters open to see if they incorporate a magnet inside of the filter. It would be cool to add a inline filter and cooler to ours and make it easier to service.

I have personally pushed quite a few Jatco 4 speeds that had over 140+ miles with a full flush, clean out, and a shift kit with our older turbo cars. The Jatco 5 speed in our G35 / 350z cars are just bigger versions of them. Honestly they are a very good transmission compared to some. If maintained well they can break into the 200k mile range before a rebuild.

 

Would you do this as maintenance? Maybe at 100k...