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2004 Infinit G35X

I own a 2004 Infiniti G35X, with 107,000 miles,which I purchase new. I have never changed the transmission fluid, drained or flushed. I am not encountering any problems with the transmission. I have received conflicting information regarding the transmission maintenance. Should I do anything in regard to transmission draining, flushing, etc.?

If you plan on driving the car for another 100k miles, you should replace the transmission fluid and filter. That car likely uses expensive synthetic transmission fluid, so this will be a couple of hundred dollars. No need for a transmission ‘flush’.

Read the owner’s manual and do what it says. Duh.

You have been very helpful. Thank you for the professional response.

First, read the owner’s manual. What does it say about transmission maintenance?

If it states you have lifetime fluid and you never need to change it then you can’t be blamed for going 107K miles with the original fluid. Lifetime fluid means lifetime of the transmission not the car, in my opinion. Not changing the fluid invites transmission failure, so I’d get the fluid changed even if the manual says “Lifetime” fluid.

Then the question is how to change it? A poorly done flush can do more harm than good. How can you tell if a place that does flushes will do it correctly? If it is a quicky lube shop, forget a flush it will not be done correctly. If it is a transmission specialty shop it “might” be done correctly.

Correctly means they drop the pan and clean it, put in a new filter and then replace the pan and do the flush. Then drop the pan again and put in another new filter and then button it up and refill with the proper fluid. This is a lot of work and will be a costly flush.

The safest approach is to drop the pan, put in a new filter, and clean the gunk out of the pan. Then put it all back together and fill with the proper fluid. Using the proper fluid is very important. An Infinity dealer should use the proper fluid and might be the best place to go. A quick lube shop will use “generic” fluid which they tell you is the correct fluid and it isn’t. A specialty transmission shop should know and have the right fluid, but some of the chain transmission shops aren’t the greatest.

Since you’ve gone 107K to this point, I’d pay the extra money and have an Infinity dealer do this job.