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Auto trans radiator cooler bypass

66K views 77 replies 31 participants last post by  guzzio 
#1 ·
Just a word here to you folks doing the transmission radiator cooler bypass. DON'T! Water cools about 32x's better and faster than air. The transmission fluid coming from the torque converter to the radiator is at a much higher temperature than the coolant in the radiator. Once the transmission fluid gets to the radiator, it is quickly cooled down to the cooling system temperature. Then it goes to the auxilliary cooler where it gets cooled below cooling system temperature. If you tow, haul or off road, put a second auxiliiary cooler in series with what you have now, or just get a bigger auxilliary trans cooler. It can't be too big, or your return flow rate will drop. If your concerned about cross contamination, get a good aftermarket radiator and rest easy. HEAT is an automatic transmissions worst enemy.
 
#54 ·
#55 ·
Dubie here is the link to what I purchased. 2 yr limited warranty. If you do the live chat, I pretended I was undecided and mentioned buying it from another online vendor. They gave me 5% off so I bought it.

CSF 3196 Radiator | Auto Parts Warehouse
Hey Mandangalo,

The part you linked to says it fits for Frontier but the dimensions show only 27x14" core dimensions. Similar replacement parts are 27x23 or so. Do you think that spec is wrong in their description or is this a smaller radiator?
 
#56 ·
Hi guys I'm new to the frontier fam as I just purchased an 06 frontier 4x4 and I'm looking to perform any and all mod to keep it running so it will outlast me, lol.
1st wtf is the radiator mod
2nd which radiator is the best one to buy. I'm finding several but dont know which one.
If anyone has replaced them with aftermarket ones please state the brand.
Thanks
 
#57 ·
I had no clue about the cross contamination until I joined this forum, and now im losing sleep over the issue. I checked my radiator fluid and thank god its still nice a green (thats good right). Is this really a ticking time bomb that needs to be fixed ASAP?
 
#58 ·
Droopy, the radiator mod is where the trans cooler, which is located inside the radiator, gets bypassed so to avoid cross-contamination between the two fluids. Price not withstanding, Griffin makes an all aluminum custom replacement that several people have installed. Its a work of art!!!

Steve Benecke
Amsoil Independent Dealer
www.lubedealer.com/code3synthetics
 
#61 ·
Is their a way to see if a transmission has been affect by the cross contamination?
Meaning if it happened and some just replaced the transmission and just flushed the transmission.
How can or do I tell if this has been the issue. Are their any signs?
The one I'm looking to buy just had a full service meaning coolant flush and trans service at 70k miles.
How can I tell that is the truth?
 
#62 ·
ummmm, no, the radiator cooler in our trucks is primarily for cold climates and has NOTHING to do with normal cooling as many have SPECULATED. It is plain and simple to aid in warming the slush box, not cool it. Screw the warranty addition as I will eventually replace the radiator with something of quality. For you that want the blue pill, please make yourself happy and leave the rest of us alone.
 
#70 ·
Is that why since I've bypassed and installed a B&M 14,400BTU cooler that I have to pull over twice while driving up to the peak of the Sierra Nevada's from Sacramento because my fluid gets up to 240-250 degrees? The internal cooler does cool the fluid. If the coolant is 170 and the trans temp is 230, how are you going to say that it doesn't cool it down?

If you live where it doesn't get real hot and you font have to tow or live in an area without a lot of elevation change, then you are OK with just bypassing. I would make sure to install a temp gauge though and keep an eye on the fluid.

Seems like you're the one that is speculating...
 
#71 ·
Just came back from my dealership as I was in getting my Honda CRV alignment done.
I spoke to the service manager about flushing the tranny on my truck and they have stopped flushing and now just doing a drain and refill. They said they have seen too many transmissions going belly up after a flush due to crap being carried around during the flush.
He said just drain and refill twice in about 10,000 miles and you will be fine, we mentioned the bypass and he said that you are covered up to 80K with warranty, my truck is a 2008 SE Crew Cab with only 30K so I am ok. He did not recommend the bypass as he said you will lose additional cooling and heating and it will void warranty if done.
He has not seen any Frontiers yet come in with transmission contamination related problems and said they are their best selling truck.
 
#72 ·
He has not seen any Frontiers yet come in with transmission contamination related problems and said they are their best selling truck.
Like they would say, "Yea, those things are JUNK and always fail." Common now. It is a Very well known issue and by such they have extended our warranties a little bit, but have really just screwed most of us by making/installing a asstacular radiator.
 
#73 ·
Another Aux Cooler?

I have read all of the posts in this thread, and have performed the bypass on my '05 (Thanks, LE!). There is a lot of discussion regarding changing the radiator out in the affected years in order to use the cooler in the radiator.....would it be easier/as effective to add an additional external cooler downstream from the factor external cooler? I found an auxiliary cooler at the auto parts store that looks like it would fit adjacent to the factory cooler, just have to figure out how to mount it. The prices are from $30 up to $150-plus. Just wondering if it would be easier to do that than replace the radiator, and wondering if anyone has installed the extra cooler, to any benefit? Also, from what I have read, changing over to Amsoil AT fluid is also a consideration. About the only towing I do is the trailer to the landfill, load of firewood in the trailer, or a small (<18') aluminum boat.....

I have been reading a lot of the threads on this forum, and am learning more every time I get on here; thanks to all of you that post your experiences, tech and how-to tips, offer assistance, as well as heads up for potential issues...looking forward to responses.....
 
#74 ·
Decided to bite the bullet and move on

My 2005 KC LE has only 30,000 miles and I plan on it being around another 8 or 10 years, so just had new aftermarket radiator, upper and lower hoses, coolant and transmission fluids replaced. Only $964...what a deal.

Don't try this at the dealer! :))
 
#75 ·
Before the Frontier, I had an '04 Trailblazer. It was a rwd, 3.73 gear, rated to tow 5600 lbs. Trailblazers have a 4.2L I6 engine. Pretty nice vehicle, but no auxilliary transmission cooling at all. Just a pass through the radiator. Everyone on the Trailvoy forums suggested adding a trans cooler, so I did. I put this one on (or a model very close to it):

transmissioncoolers.us: Hayden Transaver Plus transmission cooler kit



When I started reading about this cross contamination issue, I thought about doing the by-pass and adding another cooler, but the stock trans cooler from Nissan seems bigger and beefier than this Hayden model. I would find it hard to believe that this truck would suffer at all from the bypass. That cooler should be more than apt, even towing a load under 5000 lbs, imo. Of course I'm no expert -- it just seems to be a really nice and big trans cooler that is already on there.
 
#76 · (Edited)
So ... here goes. I'm from Belgium, so excuse me if i write spelling mistakes.

I have a Nissan Navara 2.5 auto diesel 2007. I tortured the search button and read different options about this issue.

As i planning to use the Nav for towing my boat in holidays from Belgium to Italy, i'm really anxious - concerned ...

I will check what kind of fluid there is in my rad. I thing the 'J' fluid.

Most enthousiast forum member or Nav owners do the bypass. But how about the heat in the tranny??? Hmmm ... doubts ...

So ... my boat weighs about 1.350 kg or 2976 IBS.

For 6 years my Nissan X-Trail did the job perfect. As the Nissan X-Trail is for the misses now, the Navara would do the yearly job to Italy.

So ... to the point.

Would the bypass would be enough?
Or would you specialists advice me to:
- put in an extra cooler?
- upgrade to a better radiator?

And if so ... which cooler? Which Rad?

Hope to find answers here.

Thanks in advance you al!!! Input is much appreciated ! ! !

Grtz. From Belgium.
 
#77 ·
This issue does not apply to your truck. It only applies to the Frontier, Xterra, Pathfinder from 2005-2010 with the 4.0 liter V6 engine. Enjoy your truck!
 
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