radiator/transmission questions and solutions?

[hankakamado]

After buying a used 06 Pathfinder, i find out about a problem that 05's and some 06 pathfinders are known for, the radiator contaminating the transmission resulting in a costly repair.

I found a sort of fix for it by bypassing the radiators trans cooler and either using an aftermarket cooler or by using the aux cooler that comes from the towing package. So far i dont see any indications that my truck also has the defect, But its got me worried. From what I've read , even cars with warranties aren't being repaired because nissans stance is that the radiator failed and that damaged the transmission, so not under warranty.

After convincing my wife to get a pathfinder, I find this out. Id like to at least do something to help prevent or at least extend my transmissions life.

If I do the bypass and the transmission still fails will my bypass mod be blamed for the transmission failure? I can see the service manager now saying ,'the mod caused the failure so no warranty'.

I was also curious if its just a bad nissan product . What if I used an aftermarket radiator? Or is it possible the design of the radiator itself is the problem?

Anyone else go though anything like this?

[Pwnin Obrien]

I'm not too familiar with the bypass but does that just involve using a third party trans cooler? I believe the issue was Nissans original design of the R51 radiator, this problem is fairly common and if the vehicle is no longer under warranty then it definitely won't be covered by Nissan. My suggestion would be to install a third party transmission cooler and bypass the radiator altogether. If you were to complete this before any coolant leaked into the trans fluid then you'll be fine. If you find that coolant has already begun leaking into the trans fluid then try not to drive the vehicle until the mod is completed and immediately have the trans flushed thoroughly. This may not completely prevent transmission failure but it may prevent premature failure in the near future.

[hankakamado]

sounds like sound advice. Ill check that asap then. Thanks.

[racerken]

Hi,

This response is somewhat related...
I've purchased both the R50 and R51 as brand new and can share some details on the transmission.

the R50 was purchased when I was in my 30's so I felt that the pedal on the right hand side provided more of an adrenaline rush than the left side. (Wide Open Throttle was a common occurance) My friends and I would locate destinations in the desert where we'd literally floor it and just steer. At about 24k miles I changed all fluids:
Transmission Fluid was very dark.
Transfer case was ok.
Rear differential was full of nice bright metal flakes.
Front was diff was ok.
It was a sad day.
Mobil 1 was the fluid change and continued changing fluids at every 12k or annum.
The transmission finally started slipping and rumbling at about 130k (10 years) so we sold it and purchased an R51 in 06.

The R51's fluids are changed like an old man (i'm in my late 40's now) with anxiety problems. I don't race thru the desert anymore but I conduct 4 wheel slides in the winter (all the time) and won't hesitate to bottom out when no one is looking. (Wide Open Throttle is not so common except when entering the freeway)
The engine oil is changed once in April and November with Mobil 1.
The transmission fluid was changed once at 50k and it was as ok.
(I waited this long because the engineers at Nissan told me that the R51's have no issues)
Transfer/front/rear cases were also ok.
The only stupid thing I did was darn near strip the rear diff plug so now there is an ugly glob of silicone to make sure it stays on until I have time to replace the rear housing cover. BTW, the R51 has a finned aluminum rear diff cover for heat dissipation, whereby the R50 was stamped steel.
I changed transfer/front/rear fluids again at 60k and everything was ok. I did this because there was this humming sound which is louder in 2WD but I think the issue is/was 60k old tires (BF Goodrich All Terrain Radials with lots of tread remaining). Anyway, the humming continued so I swapped tires yesterday. No testing for humming yet.

Here is my point and question:

I am sure that my aggressive driving caused the overheating hence death of the R50 transmission. I'm sure a cooler would have helped me somewhat.

I am sure that normal driving with the R51 is allowing me to maintain normal fluid changes without a cooler. (BTw, I live in Michigan so I have 4 seasons)

Pwnin, do you know for a fact that the R51's have transmission cooling problems?

I'm thinking about installing one of these:
http://www.bmracing.com/PRODUCTS/Automa ... perCoolers

With regards to warranty, when you make changes to original equipment, the dealer or Nissan Warranty people will want documentation on what you did and when. If it makes sense, then they will allow your change. (this is what the Nissan Tech Center people informed me.) I had an 04 Porsche and conducted all of my maintenance and kept all receipts for oil/filter. When the one of the engine bearings failed (outside of warranty), Porsche paid for the engine but not the labor to replace it.

What Towing Package and/or cooler are you planning on using?

Ken