I've read a few threads lately where folks are getting rid of their 5th gen Maxes/I-30/I-35 cars due to transmission issues. Just wondering if a plumbing in a small external cooler might make sense for our cars to promote longevity. I did it on my old '99 Q45t, but didn't keep it long enough to measure any difference. Anybody have one installed and seen improvement in shifting, reduced fluid degradation...etc?

 

The autos already have tranny coolers. They run fluid to the radiator where it passes through a tube and back to the tranny. Probably not the most efficient but it's there. It should be very easy to unplug the lines from the radiator and into a finned cooler.

 

I use the cooler return line in my 03 auto to exchange fluid. It's so easy. Do it that way in my truck also

 

I know how to do it, the question is...is it worth it? To me, seeing how much lack of space there is under the hood for air circulation compared to other japanese V6's from that era, I have my doubts about the radiator doing the job over the long haul in this car. One might even be inclined to bypass the radiator altogether to avoid an internal crack, allowing coolant mixing with it, spelling complete disaster. What do you guys think?

 

I haven't heard of the strawberry milkshake being an issue with Maxima's, but I think an external oil cooler is a good idea due it being more efficient

I was kinda forced to buy one because I went with an all aluminum radiator and it didn't have the transmission lines
Got a B&M cooler because of the features

 

All the cars and trucks I've owned recently have internal radiator coolers at minimum. Never had an issue with cross contamination or failure. Heat is the number 1 killer of transmissions so any kind of cooler is critical to transmission longevity. I performed the radiator support replacement, had the whole nose off my 03. In my opinion the radiator and cooling fans are sufficient for that car. The only thing that might effect cooling would be the ac condenser being clogged or fins flattened preventing flow.

Used as example my 06 Escalade has a gauge for transmission temp and an additional external cooler mounted in front of the AC condenser. It maintains approx 180f on real hot days. I'm considering upgrading the external cooler with a fan. As a rule, under 200f is good. Over 200f not good. Over 250f death. I don't know what the maxima transmission temp is. No gauge. But I do know cooler is always better. So no way I would delete it. If anything I would add a external cooler. External coolers are not large enough to block or hamper flow if mounted correctly.

 

I suppose climate has more affect than anything...other than frequent fluid changes. I don't have external cooler but drain and fill every 7000 miles and live in upper Midwest so blazing hot summers are not affecting it.

Multiple variables i would think. If I lived somewhere hot or did a lot of stop and go driving i would have an external cooler and continue to drain and fill often.

We can't blame cars if we don't keep fluids changed and at the proper temps.

 

^^^^^ ... correct, I agree with the above statement.