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I by-passed my in radiator tranny cooler

Posted: Mon Aug 24, 2009 12:39 pm
by ajporter03
This is my first post, I haven't had my Pathfinder too long. But I have an 05, with just over 50,000 miles on it. I have read more than enough about people having problems with coolant mixing with their tranny fluid causing thousands of dollars worth of damage. So I picked up a B&M Trans cooler. Part Number 70268. I installed it in place of the cooler inside the radiator. Now the tranny fluid flows through the B&M cooler, then the stock cooler and back into the transmission. The setup seems to work great. No problems so far.

Posted: Mon Aug 24, 2009 5:00 pm
by NVRDONE
We did a similar change on my 06 Pathfinder & my shop forman's 05 Frontier.
Since the radiator cooler is so small, we just bypassed that cooler by using a double ended barbed fitting & clamps. By using the auxaliary cooler all ready on the truck, we havent had any problems & I tow a 19' boat !!!

Re: I by-passed my in radiator tranny cooler

Posted: Mon Aug 24, 2009 5:46 pm
by 2008PatherfinderS
ajporter03 wrote:This is my first post, I haven't had my Pathfinder too long. But I have an 05, with just over 50,000 miles on it. I have read more than enough about people having problems with coolant mixing with their tranny fluid causing thousands of dollars worth of damage. So I picked up a B&M Trans cooler. Part Number 70268. I installed it in place of the cooler inside the radiator. Now the tranny fluid flows through the B&M cooler, then the stock cooler and back into the transmission. The setup seems to work great. No problems so far.
If i read your post right, you have the fluid still running through the stock cooler. If that is true, you still won't be protected if the radiator cracks internally and leaks coolant into the stock tranny cooler. You need to bypass the stock cooler completely.

Re: I by-passed my in radiator tranny cooler

Posted: Mon Aug 24, 2009 7:11 pm
by disallow
2008PatherfinderS wrote:
ajporter03 wrote:This is my first post, I haven't had my Pathfinder too long. But I have an 05, with just over 50,000 miles on it. I have read more than enough about people having problems with coolant mixing with their tranny fluid causing thousands of dollars worth of damage. So I picked up a B&M Trans cooler. Part Number 70268. I installed it in place of the cooler inside the radiator. Now the tranny fluid flows through the B&M cooler, then the stock cooler and back into the transmission. The setup seems to work great. No problems so far.
If i read your post right, you have the fluid still running through the stock cooler. If that is true, you still won't be protected if the radiator cracks internally and leaks coolant into the stock tranny cooler. You need to bypass the stock cooler completely.
No, you read wrong.

Remember that stock there are 2 coolers, the one in the rad (suseptible to the failure) and the oil/air cooler up front.

Posted: Tue Aug 25, 2009 8:46 am
by NVRDONE
Ok, so I was tired & maybe wasn't clear. We simply bypassed the trans cooler in the bottom of the radiator. Used a barbed connector & clamps on the trans hose. Also capped the trans cooler conections at the bottom of the radiator.
All seems good after a 2400 mile run from Seattle to Ca & back.

Posted: Tue Aug 25, 2009 2:52 pm
by kramer
Can you snap some pics of the setup maybe? What size hoses and fittings did you need?

I'd like to do it too. Did you have to remove stuff to get to it or was the install pretty straight forward?

Posted: Tue Aug 25, 2009 4:25 pm
by NVRDONE
I wouldn't have a clue as to how to post pictures, but this was extemely easy to do.
I simply removed the front skid plate for access, disconected the hoses from the trans cooler at the radiator, spliced them to gether with a 3/8" double ended barbed hose conector & hose clamps. Then I took 2 rubber vaccume caps & clamped them over the conections at the trans cooler in the radiator so I wouldn't loose coolant if the divider between the trans cooler & radiator ruptured. Then I wire tied the hoses up out of the way & re installed the skid plate. Took all of about 1/2 hr to do it.

Posted: Wed Aug 26, 2009 3:20 pm
by kramer
Oh okay I understand now what you did. I'll do the same.

Posted: Thu Aug 27, 2009 7:43 pm
by ChitownPathfinder
I just did this same mod, but used Nissan Part number 21533-EA50A Tube-joint ($15.00) to bypass the radiator . All the bolts to be removed are 10MM and there is 12 of them. Took about 45 mins

Posted: Thu Aug 27, 2009 8:13 pm
by ajporter03
I am kind of surprised that you guys don't seem to be too concerned about taking away cooling capacity by bypassing the in radiator cooler and not replacing it with something else. I was a little concerned that the B&M cooler that I added in wouldn't be adequate to make up for bypassing radiator. You guys are a little braver than I would be.

Good luck.

Posted: Thu Aug 27, 2009 8:35 pm
by ChitownPathfinder
This is a good read for anyone considering this mod http://www.clubfrontier.org/forums/f8/t ... ure-34877/

Posted: Thu Aug 27, 2009 8:41 pm
by ChitownPathfinder

Posted: Thu Aug 27, 2009 9:55 pm
by kramer
ajporter03 wrote:I am kind of surprised that you guys don't seem to be too concerned about taking away cooling capacity by bypassing the in radiator cooler and not replacing it with something else. I was a little concerned that the B&M cooler that I added in wouldn't be adequate to make up for bypassing radiator. You guys are a little braver than I would be.

Good luck.
Someone else probably knows better, but the cooler inside the radiator is either just a reservoir or a very small heat exchanger. I'd wager a bet that its purpose is not to cool the trans fluid but instead to maintain a regular temperature, and in cold climates, help the transmission warm up faster.

These trucks are equipped with a larger external cooler anyway, so you're not really taking away any cooling capacity IMO, at least not anything worth noting. The one and only thing that I would expect is perhaps slightly harder shifts in really cold weather, before the transmission warms up on its own.

Most cars/SUVs don't even have a single transmission cooler, so don't worry, you're still way ahead of the game.

Re: I by-passed my in radiator tranny cooler

Posted: Fri Aug 28, 2009 5:54 am
by Cooper993
ajporter03 wrote:...So I picked up a B&M Trans cooler. Part Number 70268. I installed it in place of the cooler inside the radiator....
Can you tell use where you mounted this cooler? Also, did you have to cut or fabricate any parts or did is bolt up easily?

My trans just failed for this same reason and I want to bypass the internal cooler as well.

Posted: Fri Aug 28, 2009 10:41 am
by kramer
I just bypassed my cooler as well, took about 30 minutes to do. Very quick and easy job, if any of you are wanting to do it but are unsure because of the work involved, just go for it. Its really quick.

You'll need a 12mm socket to remove the plastic valance and skidplate, there are about 10 bolts or so.

You'll also need a 5/16" double ended barbed brass hose fitting like this one:
Image
Don't bother ordering the Nissan hose joiner for $15, it's a waste of money. The barbed hose fittings are like 2 bucks.

Finally, you'll need some vacuum caps, I believe the size is 3/8" internal diameter to plug the radiator outlets.

The write-up with photos in the link above is spot on, its very easy to do. I'm not gonna bother installing an aftermarket cooler as the stock one outside of the radiator is plenty big enough.