I bought my neighbor's 2001 Nissan Maxima GLE. It's an automatic with 119,000 miles.

I want to change the transmission fluid and install an inline transmission fluid filter (from Magnefine). I've used inline Magnefine filters on my other vehicles. They install in one of the transmission fluid lines that leads from the tranny to the radiator (or back).

However, my mechanic said that he thinks that in my '01 Maxima, there aren't lines that take the tranny fluid from the tranny to the radiator. Instead, he said, he thinks that radiator fluid is circulated to the transmission. If so, I guess that means I can't use a Magnefine filter as there would be no transmission fluid line to put it in.

Can anyone tell me if my mechanic is right? If he is right, is there no way to install a Magnefine filter? If he is wrong, where can I install the Magnefine filter, and what size is the line I'll be installing it into (5/16", 3/8", 1/2" etc.).

 

Your mechanic is wrong. The auto trans has 2 rubber hoses that go to the bottom tank of the radiator. If you open the hood and look down, you can see them.

I don't know what size the lines or fittings are. You have to remove the plastic air shields on the bottom of the engine to access the lines. If you pull a cooler hose off, you won't get very much oil leaking out as long as the engine isn't running. I similarly don't know where you can mount you filter. Part of any answer depends on how big the filter is. The only room there is is behind the passenger headlight.

Here is a picture I took of my new radiator when I had to replace it. If you look at the bottom, you will see 2 brass connectors. These are for the auto trans oil cooler.

 

Hi Dennis,

Thank you for your answer and photo. A couple of extra questions to clarify:

Are you certain those connections are for transmission fluid coming from the transmission to the radiator rather than coolant going from the radiator to the transmission? My mechanic said they were the latter, that they carry coolant, not transmission fluid. And he just replaced the hoses on my Maxima.

Also, do you have a 2001? I think I read somewhere on here that the 2001 has a different engine than the 2002 and 2003 models.

I'm not suggesting you are wrong. I just want to be as certain as possible.

 

It has Tranny fluid like Dennis said....no need to ask again, I'm sure.

 

Wow, okay, thank you both for your answers.

I just can't understand how my mechanic was wrong about this. He's been a mechanic for 20 years, including at a Toyota dealership and now has his own successful shop that employs several mechanics. He has never steered me wrong. Most of all, I just took my Maxima to him to have all of the coolant hoses replaced (preventative maintenance). It was right after doing that that he told me that.

Do you happen to know what size those hoses are?

 

 

Bronx: Thank you for that. I'll have to go to my mechanic and ask him what's up. He installed an inline Magnefine filter on my Sienna nine years ago. I've had very good luck with it (at 80,000 miles the ATF had never been changed, I put on the filter and Amsoil ATF, and the transmission now has 192,000 miles and is running perfectly).

I'll call the dealer tomorrow. Maybe they can tell me the size (diameter) of the hoses (it's necessary to know to order the Magnefine filter).

Thanks again!

 

I further confirm it is transmission fluid. I added a transmission cooler years ago on my 2000 (same build) using those lines. If I recall correctly they are 3/8-inch.

You should have room for an in-line transmission filter between the radiator and transmission. It will just be a question of how to physically mount it. Beyond that, it is a piece of cake to rerun the lines yourself.

 

It will come as no surprise to all of you that you were right, those are transmission oil lines going from the tranny to the radiator and back.

I put a 3/8" Magnefine inline transmission fluid filter in the return line (the one that carries ATF from the radiator back to the transmission). I had just finished running AutoRX through the transmission, and I had it flushed and then filled with Amsoil signature ATF. I did the same thing with my Sienna years ago, and, even though the transmission hadn't been serviced at all before I bought it with about 80K miles, the transmission in it is still going strong at 192K miles.

Thanks for all the replies!