My early 03 G35 sedan with 5AT just turned 113k miles. It has been totally trouble free -- all I've had to replace is brakes, batteries, bulbs, belts, and tires. Oh yeah and I had to wire some heat shields together to keep them on after rusting a bit. Just replaced the plugs too.

Got to thinking about my transmission while idling in traffic today so I pulled out my serivce interval guide. It has a line for differential and automatic transmission fluid and I see some I's (for inspect) but not R's (for replace).

I've never replaced my transmission fluid and am a firm believer and not doing anything more than what is specified by Infiniti (forget about the dealer - I trust the manufacturer over the dealer).

Am I reading the recommended service interval book correctly? No AT fluid changes?


Thanks,
Brian


Thanks,
Brian

 

It is recommended to change it at every 100k KM. I changed mine at that milestone and the transmission shifts better and revs a bit lower now. It also doesn't act up anymore after sprinted runs.


So you should definately change it as soon as you can lol.

 

nogood,
Not doubting you but where did you find that? I'm pretty religious at following the manufacturers service recommendations but since the book I have didn't recommend it, I haven't done it. It seems kinda nuts so I thought I'd ask - plus if I should be looking at some other schedule, I'd like to know about it. Maybe it's an early 2003 thing? Keep in mind my car (built Jan 2002) doesn't even have a transmission dipstick,


I've also heard some wife's tales about how a transmission fluid change after too long "stirs up" all of the particles and junk that has settled over the years and miles. That makes no sense to me - as the fluid change procedure pumps the fluid through the same passages fluid flows due to normal operation. What are your thoughts on this tale?

Brian

 

Hmmp. Mine is at 95k. Wondering if I should change too

 

Have a look at Infinitihelp's site. They have all the schedules available.

It was listed at 100k KM, my friends at Infiniti also suggested I should change the oil. I'm glad I did it because the car feels much better now.

Just make sure you use OEM trans oil and not any other brand. Also, just a drain and fill is good. I didn't want to do a flush because it may damage the trans with its pressure.


So I really suggest you do it even if your car drives fine right now. Since I push mine and drive hard sometimes. It was overdue.

 

I also changed the differential oil at the same time.


It looked so bad and smelled horrible when draining both lol.

 

While Nissan S-matic tranny fluid is quite pricey at $8 to $10 a quart, I can assure the replacement cost the Jatco 5AT in your car is far more expensive. You REALLY should replace the tranny fluid ASAP. Tranny fluid is just like any other fluid in a car. It has a life expectancy. The primary killer of automatics is heat. Heat will breakdown the fluid over time and will dirty up with small peices of clutch, band, and other materials. High mileage and old ATF, can and will reduce your tranmissions life expectancy. I can assure you of that.

I would recommend picking up about 10 qts of S-matic fluid (use to be called J-matic) and doing three tranny drain fills. It's simple. With a cold engine/tranny, raise the car up in the front and remove the transmission pan drain bolt. Lower the car and let the tranny drain. Measure what came out and add the same amount. Drive for a couple days. Do the procedure twice.

With my car, I did three drain/fills at 60K miles and then do one drain/fill every 20K miles. I drive my car hard so I do what I can to preserve the tranny.

 

^ Great advice.

 

Ok Ok ok you guys scared me into it. Just ordered 11 quarts and a dipstick and will flush next weekend. Still don't understand why my Inifiniti service schedule does not recommend it all they way through 200k miles.

Have to admit that on the hottest days of the year the transmission "bucked" a few times at highway speeds on mild acceleration. Hasn't done it once since the 95 degree days.

Thanks for the reality check guys
Brian

 

Personally, I would not change the fluid because you have so many miles on it. It is not some old wives tales about not changing fluid after you have a lot of miles on it. Over time, the clutches in your transmission will wear and the material that was on the clutches will now be floating in the fluid. Since you have so many miles on your trans and never changed the fluid, there is a good chance that the fluid is playing a big part in holding the clutch material and keeping the trans working. If you change it, the clutches may not be able to keep friction and the trans could very well start slipping and you will need to replace/rebuild it.

If you don't believe me, just read about it.

http://www.trustmymechanic.com/transslip.html

There are tons of other sources online that basically say the same thing. You should change it every 50k miles or so, I say you are way too far gone now.

 

Agreed about the clutch material in the tranny fluid, if it were a domestic with that many miles I wouldn't touch it. Being an import tranny I would take into consideration how much abuse the tranny has seen. If you have put most of those miles on your car and you aren't too hard on the tranny I would personally change the fluid now.

 

Completed the transmission fluid change today. After 10.5 quarts the fluid coming out was still dirty but I only ordered 11 quarts so I called it quits. The biggest surprise was how precise one needs to be with the amount of fluid to get a good reading. I had placed about 1/3 of a quart too much and the reading was very high so I opened the drain pan and let some out.

The good news is that the transmission does not slip with the new fluid. The old fluid was pretty dark but was not smelly or otherwise suspicious. I'm not too surprised as almost all of my driving is highway - 50 miles a day to/from work so the transmission has had a pretty easy life.

Also had professional interior/exterior detailing done at Delta Sonic (local super deluxe car wash chain) as a gift through groupon and the car hasn't looked this good since 2005. Looking good and feeling good. Now if those bubbles starting to grow on the right front fender like rust pimples under the paint would just stay small.....


Brian

 

^ Good to see someone post with actual experience changing fluid in a higher-mileage 5AT, definitely keep us posted if anything changes.

Mine is on the high side, too (nearing 140k km) so even a drain and fill worries me a little.

 

Thanks for updating. Strongly suggest you replace your diff fluid now ASAP. That's easy to do yourself, if you can get under the car and get some funnels. Or just bring it to Nissan.

 

Well my car is at 88k miles,
The owner before me was a woman who didnt drive it hard at all for 50k miles.
I havent put too many miles on the car...

Change it or leave the atf?