# 06 pathfinder transmission question



## bud123 (May 8, 2012)

How is the radiator coolant getting into these transmissions? What can we do to stop this from happening before transmission is ruined. I read someone block it off. What does that me?
Bud123


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## IanH (Feb 11, 2003)

From what i have read on here the coolant gets into the trans fluid cooler circuit because of cracks in the radiator (due maybe to poor manufacturing.)

Since I have towed heavy loads in the past I have re-routed the cooler lines to a separate air transmission cooler. this gets rid of this risk.
However my 2003 will not go into converter lock / highest gear until the trans is warmed up. Check if yours is the same. If it is then you must get a cooler with a thermostat to help raise the trans temp ASAP. I expect you will still have a bigger delay, mine "works" after about 2-3 miles after the radiator fluid is up to temp, and i suspect its acting as a heater at this point.

Other alternative is a new radiator that hopefully wont have this issue. Maybe a performance all aluminium with the trans cooler ? these aren't cheap but it would be much cheaper than a re-built trans AND a new radiator.


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## IanH (Feb 11, 2003)

see this link

http://www.nissanforums.com/pathfinder/170051-radiator-transmission-failure-probability.html


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## smj999smj (Jan 1, 2006)

The issue is that the cooler tube for the auto trans fluid in the lower tank of the radiator cracks. The coolant system runs at a higher pressure than the pressure of the ATF in the cooler tube, so the coolant pushes into the cooler tube and gets sent to the automatic transmissions, where it will contaminate the fluid, turn it into a pinkish custard and ruin the transmission. This issue is a concern on 05-10 (R51) Pathfinders (not the 96-04 R50 Pathfinders), as well as the same year Frontiers and Xterras. So far, the heaviest hit have been the 05-07 models, although a couple of 08 models are starting to experience the problem. Nissan has extended the warranty to 8 years/80000 miles, but often this occurs after 80000 miles. The result is usually a repair bill in the neighborhood of $6000. Currently there are class action lawsuits against Nissan and consumer groups, as well as individuals, petitioning the NHTSA to make Nissan recall the radiators. What most have done in the meantime is bypass the radiator's cooler tube. Most (if not all) R51 Pathfinders already have an auxiliary trans fluid cooler mounted from the factory, so purchase of a cooler is not necessary. The other option is to replace the radiator. Updated radiators from Nissan cost a ridiculous $530, but aftermarket replacements can be had in the $90-$125 range (I just bought one for my 06 LE for $92 off of Ebay, including shipping and a lifetime guarantee.) You can find a lot of information about this problem and the "bypass procedure" at one of the many Pathfinder or Xterra websites, such as www.thenissanpath.org

Nissan extended warranty info on the radiator (refer to the menu on the left, "radiator assembly"):

NissanAssist.com


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## IanH (Feb 11, 2003)

smj999smj can you answer the question about the transmission engaging the lock out and or O/D with transmission temperature on the 06 ?
Will by-passing the cooler cause a problem that will affect this and lower gas mileage ?


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## bud123 (May 8, 2012)

So to keep this from happening I should just have a new radiator installed at our local radiator shop? I will not let a Nissan dealer touch this truck. Those guys know nothing.


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## IanH (Feb 11, 2003)

bud123 said:


> So to keep this from happening I should just have a new radiator installed at our local radiator shop? I will not let a Nissan dealer touch this truck. Those guys know nothing.


Yes that seems like its the best plan.


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## smj999smj (Jan 1, 2006)

IanH said:


> smj999smj can you answer the question about the transmission engaging the lock out and or O/D with transmission temperature on the 06 ?
> Will by-passing the cooler cause a problem that will affect this and lower gas mileage ?


Once you start driving, the trans fluid is going to heat up pretty quickly. Of those that have done the "bypass," I've yet to hear a single comment about performance issues, including O/D engagement or gas mileage. Yes, the trans cooler in the radiator does, in addition to help cool the ATF, help get it to operating temperature quicker, but, unless the vehicle is in an extremely cold environment, I doubt that it will an issue having the cooler by-passed. I debated back and forth on the issue on whether to do the bypass or to replace the radiator. I just felt better going the route of replacing the radiator, especially since I'm due for a coolant service, anyway, and being close to 100,000 miles, figured it's a good time to install a new, Nissan thermostat. Being a former Nissan tech, labor cost is not an issue, so the cost of parts, to me, is cheap insurance and piece of mind not having to worry about pressing my luck with the original radiator. It's a lot more work and expense to replace the trans, obviously! I'm also keeping the original radiator just in case Nissan finally does decide to do the right thing and recall them.


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## smj999smj (Jan 1, 2006)

Here's another link you might be interested in, that discusses a large consumer group petitioning the NHTSA to force Nissan to recall the radiators:

NCCC Asks for Recall of Nissan Vehicles for Catastrophic Transmission Failures


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## bud123 (May 8, 2012)

Thanks guys for your help. I'm gonna play it safe and order an aluminum radiator off Ebay for $135. I really do like this truck but I have to make it right.
Bud123


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## smj999smj (Jan 1, 2006)

The 05-06 models had a lot of problems. The good thing about buying one now is that you hope the previous owner(s) have mixed most of the inherent problems with these trucks. Problems include the fuel level sensor, the radiator, catalytic converters, oil pressure sending units, transfer case leaks and the upper timing chain tensioner "feet" wearing out, causing a timing chain whine. A common complaint on these vehicles is the rear suspension bottoming out over large dips and poor ride quality. This issue is addressed with switching to monotube shocks in the rear (ie Bilstein HD, KYB Gas-adjust, Monroe Reflex) and installing Airlift 1000 air bags in the rear. The rear shocks run about $75 each and the Airlift 1000's run about $80 for the set of two. Airbags are best setup with individual lines and run about 10-15 psi, unless the vehicle is towing something, and then they can be set higher. TheNissanPath.com has a ton of info on the R51 Pathfinders.


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## bud123 (May 8, 2012)

You are correct on the bottoming out. I like your reccommendation for the shocks and air ride. So far no riding or handling problems in the front. I'm getting ready to order an aluminum radiator off ebay for only $94.00 free shipping. Nissan wanted $550. I want a new radiator before the one on it destroy's my tranny.


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## IanH (Feb 11, 2003)

just as a point of interest, my 2003 has just a Aluminum looking pipe that runs across the width of the radiator and Does not use the radiator !!!


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## bud123 (May 8, 2012)

*Update on radiator/transmission by pass*

Mechanic had my 06 Pathfinder on lift and saw no coolant leaks. I guess I was lucky on this issue. However, I still had him to by pass the radiator. He took the two lines off the bottom of the radiator and put them on the cooler in front of the condensor on passenger side. Now it goes from transmission to cooler and back to transmission. Problem solved. No driving issues so far. Thanks to all on this forum for info on this by pass.
Bus123


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## smj999smj (Jan 1, 2006)

He wouldn't see leaks up on a lift. The only evidence of a cooler tube leak would be signs of coolant on the trans dipstick or ATF in the coolant. The leaks occur inside the bottom tank of the radiator.


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## bud123 (May 8, 2012)

You are correct. He checked the tranny oil and it looked good. Every Pathfinder I see I tell them about this forum and to correct the problems before it happens. Such a simple fix to save $5,000 dollars.
Bud123


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## smj999smj (Jan 1, 2006)

Yeah...I just had the upper chain tensioner problem surface on me, today! At least it went before I put the radiator in it! Guess I can kill two birds with one stone...maybe I'll kill three and do the spark plugs at the same time since I have them and there's 98000 miles on it.


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