Choosing trans cooler mod for R50

[Matari]

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Hello everyone I’m planning to do a trans cooler mod on my Pathfinder. mostly for off roading/towing a trailer. I’d really appreciate some advice. I live in a hot country most of the year during summer, it hits about 50c (122f). I have about three months of nice weather around 15c (60f) for dune off roading.

I added an OEM cooling fan (from another Pathfinder) alongside the existing one, so now I have two fans in front of the condenser and radiator. Because of that, I’m hoping to go with a flatter trans cooler if possible. If anyone has a parts list or specific recommendations, that would be fantastic.

 

also, I’ve also seen some mention of a filter would you say that’s essential? Any other tips or things to watch out for would be really helpful. Thanks so much.

 

[adamzan]

I have used these for years and they work well for a transmission filter:  https://magnefinefilters.com/

 

As far as coolers go, anything in addition to the OEM radiator one will be a bonus, but the stacked plate type seem to be preferable over the older fin and tube style. I have a Hayden one, but not sure what is available over there.

[Matari]

I see thanks. I was able to find the filter online for about $40, and the Hayden coolers are available here as well, so I’ll look into which size would be best for my setup.
Another question regarding the installation what’s the best configuration for running the lines.

[alexg89]

On 3/15/2026 at 8:48 AM, adamzan said:

I have used these for years and they work well for a transmission filter:  https://magnefinefilters.com/

 

Not to hijack this thread but This is something new i have never seen. a magnetic inline filter?

 

Where would one stick this? kinda want to get one on my 2022 pro4x but do they hinder flow at all?

[Slartibartfast]

I'm running a Magnefine on mine as well. I don't know that it's strictly necessary, but I wanted to give my high-mileage slushbox every chance I could, especially after seeing a little glitter in the fluid when I flushed it. 

 

I routed the lines on mine so the fluid goes from the trans, through the stock cooler in the rad, through the aux cooler, through the filter, then back to the trans. My thinking was that the OE cooler can only bring the fluid temp down to the coolant temp, so it should be the first stage. I put the filter on the return side just in case the cooler (which was not new when I installed it) had some schmutz in it.

 

On 3/18/2026 at 9:25 AM, alexg89 said:

do they hinder flow at all?

 

That I don't know. But I've had the filter on mine for the last 30k miles, and it hasn't complained.

[Lock]

I did the same with my auto. I don't tow but I just don't want the auto to break. Like yours it went into the radiator cooler, through the Hayden aux cooler and to a magnefine filter.

I took the trans out at like 177,000 it still shifted great, so I think it helped. Didn't seem to do any harm. 

When they were plastic you could unscrew and open them. When replacing them I'd take the magnet out and keep it. Looking at the magnet and filters you could definitely see they caught some stuff. Better than the standard pan for sure.