upgrade transmission cooling

[AceSpades]

Looking into upgrading the cooling for the V8 auto transmission, im going to be towing a 2500lb boat + cargo and family of 4 up Big Bear mountains in SoCal, which is a pretty steep incline and for long periods of time.

Before getting into additional cooling, what are your thoughts on bypassing the flow to coolant radiator? Are they known to be common failure points on 4Runners? The thought of a failing radiator mixing coolant with transmission oil is quite scary, and the Nissan guys are well aware of this common problem on Frontiers and Pathfinders, so id like to be cautious in this area

Options for additional cooling:
-replace original with larger cooler - any Brand /Model suggestions?
-keep original and add secondary oil cooler?
-water mist spray the oem cooler - I do this on my Ford V8 and works great! Im contemplating to go this route especially since i already have the hardware... Here are some pics below, its a pieced together kit and a custom bracket i made with scrap material laying around

 

[MT Runner]

I don’t know that adding an additional cooler would be necessary. From my understanding, the one you have pictured is already basically a second cooler. The tranny fluid line goes from the tranny to the bottom of the radiator first through a built in cooler there, then out to the auxiliary one, back to the tranny.

I’ve never heard of anyone having issue with a failing radiator mixing fluids on the 4Runner, but doesn’t mean it hasn’t happened. I just don’t think it’s a common issue.

I’d say replace the stock cooler with a bigger unit and then add that water mister if you already have the parts and know how to install it. That should be plenty.

I’d rather have more protection than less when it comes to transmission cooling too, but you’re well under half of the rated towing capacity, you should be just fine.

The only other thing I’d recommend is to get a scangauge or something similar so you can actually monitor those temps in real time.

 

[AceSpades]

Correct, it is well under the towing capacity, however Big Bear Mountain hills are very steep and go for long periods of time on top of 95°+ weather with the AC running and family of 4 with baggage, and boat. I cooked the transmission oil in my Expedition many years ago when i wasnt aware of how critical transmission fluid temps were. The 2nd time around i installed the water spray mist on it and was armed with Torque Pro app to monitor fluid temps, the water mist kept trans temps happily below 212°. That SUV has now been sold but i kept my water mist creation, and im debating which route to take for the 4Runner as we're planning on going again this July

 

[MT Runner]

I totally understand. I have the V6, so it only came with the cooler that’s inside the radiator. I added an aftermarket cooler and the scangauge to monitor it all.

I tow a roughly 3,500lb camper a few times a summer around MT and hit some steep and/or long hills and passes and I’ve never had the temp go above 225 while going up one of the hills.

I just think with a new, bigger cooler and then your misting gadget you’ll be fine.

 

[KBToys]

I think the 3rd gen 4runners had the issue with the transmission cooler cording in the radiator but haven't heard about the 4th gen

 

[81runner]

HD High Performance Radiator, FJ Cruiser, 4Runner, Tacoma 4.0L V6 - Underdog Racing Development

Why not just cool everything better?

 

[Chubbypanda]

On my 3rd Gen I upgraded my radiator cooler and added a transmission cooler. I didnt bypass the transmission at all.

Maybe replace your radiator to a larger radiator and replace your transmission cooler to a larger one. Then run them in tandem from radiator to transmission cooler and back to transmission. After that add the mister.

 

[KIKNROX]

What was the final Verdict on this? I'm running an 07 4th gen V6 2WD and towing at my max at 5,000lbs with Vehicle trailer and race car. The V6 didn't come with the external cooler to begin with. So going to add that.

Saving up for upgraded radiator:

BladeRunner Street Series Radiator | aFe POWER

Would also be interested in that water sprayer as well...

 

[apv97]

What's the verdict on this? I have a 2004 V8 4Runner and am towing about 6000 lbs over the Rocky Mountains at up to 11k in elevation, so was strongly considering upgrading my stock transmission cooler to this B&M one.



Has anyone done this? I saw lots of installs on the V6s (which don't have a stock cooler). Is upgrading to B&M on the V8 as simple as plug and play with the existing hoses and brackets?

 

[Bluesky 07]

What's the verdict on this? I have a 2004 V8 4Runner and am towing about 6000 lbs over the Rocky Mountains at up to 11k in elevation, so was strongly considering upgrading my stock transmission cooler to this B&M one.



Has anyone done this? I saw lots of installs on the V6s (which don't have a stock cooler). Is upgrading to B&M on the V8 as simple as plug and play with the existing hoses and brackets?

Semantics perhaps, but I believe V6s (with the tow package) don't have a stock external cooler.