[2004infinitiFX35]

I just purchased a 2004 fx35 with 117,000 miles on it and the previous owner maintained the vehicle meticulously at infiniti dealership, I pulled the service records and he performed every 30k infiniti dealer service (oil change, transmission fluid change, both air filters, coolant change, throttle body, fuel system, differential fluid, at about $800 each time) aside from the dealer oil changes, etc. I was thinking to do the 120k service early and do the spark plugs (I don't see any records for plugs changed) ,maybe flush engine, and do transmission.

Question is should I flush at this point or just do a full 12 quart drain and fill? Also the transmission from what I learned has no filter, I assume they will just remove the mesh screen, clean, and put back in?

Thanks for any and all responses in advance!

 

[happybb]

check the color of the fluid before and change spark plugs after inspecting one

 

[Carguy75]

I would not flush anything. You will risk dislodging sludge and other sediments in the engine or transmission and cause problems. I would flush only the transmission by manually flushing it with fresh fluid by opening the transmission cooler return pipe and pouring fresh fluid until the old fluid is removed. However, do not use a suction type of flush system or power flushing on your transmission. I would change the sparkplugs due to the age of the plugs. New plugs can not hurt the engine and maybe give you back some lost MPGs. To my understanding the transmission do have an mesh filter in the pan which can be cleaned. I would probably wait until the 200K mark, but it can not hurt to do it now if you want. If the engine is running fine, just keep doing what the previous owner did and leave well enough alone.

 

[Jeff191]

At 120K, don't flush it. And how would you drain 12 quarts? Even if you drop the pan, you won't get everything. The fluid in TQ convertor won't come out. If you use the method of pulling the cooler line, you still won't get it all. Doesn't really matter though, it will help.

 

[Carguy75]

At 120K, don't flush it. And how would you drain 12 quarts? Even if you drop the pan, you won't get everything. The fluid in TQ convertor won't come out. If you use the method of pulling the cooler line, you still won't get it all. Doesn't really matter though, it will help.

The cooler line method will remove all the old fluid because the new fuild will flush out the all of the old transmission fluid in the system. It is like flushing out your old brake fluid in a way if you did that job before. However, with the transmission fluid you will add new fluid in to the transmission dipstick hole while the FX is running and the old fluid will be pushed through the transmission cooler outlet into a drain pan. You keep adding new fluid until only new reddish transmission fluid is coming out of the transmission cooler outlet instead of the old dark used transmission fluid and then you will stop the process. That method will remove 99.99% of the old transmission fluid.

 

[2004infinitiFX35]

Thanks for the responses. I think I'll just do a cooler line fluid exchange, sounds the safest.

 

[JustAsking]

I am looking at buying an Fx35 what has some acceleration hesitation - anyone have insight or experience trying a transmission fluid cleanout to attempt to resolve this?

 

[mwr]

By "hesitation" are you talking about transmission slip? If so, then yes... I think you might be able to regain the "rocket affect" off the line and when accelerating in 3 gear by fully changing your transmission fluid.

Note: The Gen 1 FX35 and FX 45 (which are the same) trannies are more robust than the 2006+ models. These trannies have a dipstick and a metal mesh screen. So don't replace the screen. And don't use a typical transmission pump exchange unit that will mix new ATF with old ATF... no matter what the mechanic says.

Instead, pull your transmission cooler return line and remove all the old ATF by starting and stopping your engine... every 3-4 quarts of fluid you drain. The process is really easy once you follow these instructions I just created after I flushed my tranny fluid in Jan-2022. Note: I used Valvoline's Max Life ATF and find it's working great vs. the 4x more expensive Nissan Matic S.

Also, don't pay your dealer to change your other differential fluids, because everything is very accessible and easy. Note: The dealer wanted $400 to change my differential fluids, and trans axle fluid in my FX45, but I bought my own fluids and had my local mechanic do it all for $125... with an engine oil change. All these fluids only take 1 hour to do! So don't go to the "Stealer" for theses services.... and you will need to educate you mechanic on which transmission cooler line to pull. I.e., on an FX35 you pull the line on the drivers side, but on my FX45 I pulled the rubber hose to the transmission cooler on the passenger side.

Here's the link you need to learn more: 2004 INFINITI FX45/35 (GEN-1) TRANSMISSION ATF FLUSH...