That way does bypass the external cooler doesn't it?

G8RADE wrote:That way does bypass the external cooler doesn't it?

I don't know. That's why I'm paranoid and want to make sure before I do it. I cant afford to get it wrong.

Also I need clarification on adding a trans cooler.

Am I adding a fan to the existing exterior trans cooler?

Or am I adding an extra cooler with no fan?

Or am I adding both?

What do you think of adding this:
http://www.howeperformance.com/accessories-coolers.htm



This would act as the connection between the two hoses.

I'm not quite following your graphic, but the outlet from the radiator should be taking the fluid to the OEM cooler mounted in front of the radiator. Then the fluid runs back to the transmission. You should be able to clearly follow the lines to see that you're not skipping the main transmission cooler, just the radiator portion.

If you follow the lines and trace them to the route of the external cooler, The rear pipe out of the tranny is the outlet to the radiator. When you take that line off the radiator it should follow to the top of the external cooler (that is the intake). Then the bottom hose of the cooler goes back to the other tranny connection.

I think many people get confused (I did) and think the bypass takes out the transmission cooler. It does not. The radiator has a built-in transmission heater..(not a cooler). This helps get the Trans temp up when first started.

This built-in heater is what leaks. You are bypassing this heater. The Trans cooler is a separate unit mounted in front of radiator, and is not effected by bypass. If that helps...

The simple instructions I have given to everyone I meet is:

• On the the bottom of your Radiator there are two rubber transmission hoses connected to the radiator with clamps.
  They are the only two, the radiator has no other transmission hoses connected.
  Disconnect them from the Radiator and connect them together.
  Secure hose.

Done...Bypassed

doctahjones has a good picture:
http://www.thenissanpath.com/viewtopic. ... 0400#60400

BigEz wrote:I think many people get confused (I did) and think the bypass takes out the transmission cooler. It does not. The radiator has a built-in transmission heater..(not a cooler). This helps get the Trans temp up when first started.

This built-in heater is what leaks. You are bypassing this heater. The Trans cooler is a separate unit mounted in front of radiator, and is not effected by bypass. If that helps...

The simple instructions I have given to everyone I meet is:

• On the the bottom of your Radiator there are two rubber transmission hoses connected to the radiator with clamps.
  They are the only two, the radiator has no other transmission hoses connected.
  Disconnect them from the Radiator and connect them together.
  Secure hose.

Done...Bypassed

doctahjones has a good picture:
http://www.thenissanpath.com/viewtopic. ... 0400#60400

Ok just did it and then came in to see if I did it right. The pics in your link are great. Thanks.

Everything looks clean and oil looks good.

So what we are bypassing is a heater, not a cooler. What if trans temps surpass radiator temps? Is that possible and would it help cooling at that point?

I tow a lot and have no problem with adding cooling. But do I need too?

DirtDgr wrote:
Ok just did it and then came in to see if I did it right. The pics in your link are great. Thanks.
Everything looks clean and oil looks good.
So what we are bypassing is a heater, not a cooler. What if trans temps surpass radiator temps? Is that possible and would it help cooling at that point?

I tow a lot and have no problem with adding cooling. But do I need too?

In theory let's say your Trans temp was 212 deg/F and your Water was 200, then yes I suppose it would act as a "pre-cool" before the Trans fluid went through dedicated cooler. But from what I have read, it's main purpose is to warm the Trans fluid to operating temp quicker, so that the transmission shifts proper and activates overdrive (5th gear) sooner. Thus improving gas mileage and (my guess)helps at getting a better MPG number on the original sticker.

You will most likely find your normal trans temps drop after the bypass, mine did about 10 deg. I also have seen no real change in MPG, but I live in the South and my Trans temp gets to operational temp quick. Those living in very cold areas will see Trans temp take longer to increase.

As for towing, I have only made a few long hauls with a fully loaded vehicle and towing about 4000lbs. Most were on flat land or foothills in 5 to 90 deg weather, and I have never seen my Trans temp go over 210 deg. I also drive at 75mph while towing when I can.. Others here tow much more and might have different results, but I don't remember many posts on overheating Trans... But there are a ton of posts on failed Radiators...

From what I am reading this seems to be an issue with models between 2005-2010 model year. Can someone tell me what Nissan changed after the 2010 model year to solve this issue? Also shame on them for handling this so poorly and not solving this much sooner. You can't tell me that Nissan did not figure out that this was a problem years ago. What would it have cost them $50.00 per truck to have fixed this issue years ago and solved this problem! Sorry for venting but issues like this just tick me off!

Well, technically and shouldn't have cost Nissan anything if they handled it right. They should have done a voluntary recall and charged back the radiators to Calsonic, who makes them. Of course, Nissan does own Calsonic, so, I guess in some ways, it would cost them, but not directly.
First of all, it is still called a "cooler," though it does function to warm the ATF in times when it is too cold, as well as cool the ATF when the fluid is too hot. It's primary job is to maintain the ATF temperature around 175-210 degrees F.
The cause of the failure is that a seal in the radiator's integral cooler may fail and allow cross-contamination. There is a YouTube vid where a trans shop removed the integral cooler, pressurized it with air and placed it in a tub of water which clearly shows the leak, for those interested. While Nissan never really stated what the did to correct the problem, one would have to assume it's this seal that has been addressed.

smj999smj wrote: First of all, it is still called a "cooler," though it does function to warm the ATF in times when it is too cold, as well as cool the ATF when the fluid is too hot. It's primary job is to maintain the ATF temperature around 175-210 degrees F.

Yes, I would 100% agree with that... Although I seldom saw 175 deg F or higher under normal driving conditions prior to bypass. 165 deg was my rock solid norm. Post bypass it's 157 deg.

Which leads me to ask if the stand alone Transmission cooler has a temp valve? If not it seems it would be competing with the radiator's built-in at temps around 165 dregs.

there is no temperature valve on the external trans cooler. IIRC, the atf runs through the external cooler, first, then through the radiator's internal trans cooler. this keeps the atf from being "over-cooled," and is sent back to the trans at it's "normal operating temperature range."

Interesting smj999smj

Ingenious design, if it didn't leak. A temp. cooler, heater, and stabilizer in one unit. I can see the benefit to... For instance if running high RPM in 4low with little forward movement, the in-radiator cooler might offer more stable cooling than the ext-cooler for a longer time. In addition to the warming benefit it gives on cold starts.

Knowing this, if I lived in a colder climate or if doing any serious 4 wheeling, I would elect to install a new unaffected radiator and skip the bypass.

Good info!

It's really not new technology. Auto manufacturers have been using radiators with internal trans coolers for decades (my 65 Mustang has one). Some vehicles not only run trans oil coolers in the radiator, but also an engine oil cooler, as well (Chevy S-10 Blazers come to mind). On the whole, they've been very reliable. Calsonic just happened to make some radiators with a faulty seal in the cooler and Nissan compounded it by not handling the problem as well as they could or should have.