Xterra/Frontier Trans Oil Cooler Bypass Experience

[Sharps40]

Anybody out there with an Xterra/Frontier done the mod (e.g. eliminated trans fluid flow into/out of the radiator lower tank therby using only the external cooler) to avoid the failure of the transmission due to water in the oil?

I don't have the leak yet, nor signs of water in the oil (checking again tonight and doing the mod in the AM) but at 119000 miles I'm about 20K past the point where the system typically fails and pumps water into the trans destroying it.

Looking for experienced input, i.e. you've don the mod, and experienced/not experienced over heating of the trans on hot days or harsh shifts on cold days, etc.

The factory cooler looks to me bigger and better than even the giant BM coolers I've run in the past on hot rods. So, I doubt that unless towing or wheeling heavy in August I'll ever see the trans hot light come on......

My radiator is still good/I'm not ready to replace. But figured I'd eliminate the potential for a Strawberry Milkshake of Death between now and late fall when I plan to do all the high mileage services (i.e. likely replace the radiator then)

 

[Bocephus]

I have done it on my old 07 Frontier and my daughter’s 07 Xterra. Pretty straightforward and didn’t cause issues with either vehicle. What year is your Nissan because, if I remember correctly, they fixed the need for this by 2010 or 2011?

My Frontier spent a lot of time off-roading (beach, URE, Harlan, Gulches, etc) during warmer months and never came close to overheating or any transmission issue.

 

[RedneckFur]

A buddy of mine was a Nissan tech, and said it was only the early models that had the transmission cooler issue. All of the later trucks, especially the ones after 2010 should be fine.

 

[Sharps40]

Mine is 2008

 

[Sharps40]

Here it is. Successful, 30 minute job. Short ride indicates no leaks and seems to function fine. Monday is back to work, 142 miles a day for 5 days a week. If it ain't a good mod, should show up soon!

Step 1......Remove the Xterra tin foil front skid plate.

Step 2: Looking from the passenger side front, the two hoses with the backed off connections are the ones that get switched around to make the radiator portion of the trans cooler a dead loop and vector all oil flow to the external oil cooler. (i.e. no more oil flowing through a cracked pipe in the bottom of the radiator). In the photo below the hoses are still in factory configuration, i have only backed off the clamps.

Step 3: Again, looking from the passenger side front, I have switched the hoses and applied the clamps. The bottom of the radiator loop was blown out with some compressed air and the hose reconnected just for neatness. You could also use clamped on caps. The trans fluid now goes straight from the trans to the external cooler and back to the trans. Starting the motor and letting it come up to temp, check for leaks up by the oil filter. I had none.

Step 4: Remove the 10mm screw retaining the trans oil dipstick, check fluid levels. Mine was fine. I'll check it again after another drive and I plan to "loose" the 10 mm screw that retains the transmission dipstick.

 

[Sharps40]

Step 5: More examination of the trans fluid.....no water noted in it, but it is varnished. (Trust me, its more red than brown.....camera/lighting does not show it true. But it don't smell burnt and I feel no grit in it.) Not supersizing, 119000 miles and no one ever changes trans oil anyway. (not even the stealer changes it when he lies and tells ya it had a 5000 point check certified platinum pre owned car make ya feel confident it ain't a turd inspection) I'll be flushing 5 to 10 qts through it though.

Step 6: Properly dispose of the tin foil front skid plate by tossing it on the trailer for the next dump run and later on enjoy the fact that you just cut 20 minutes off accessing your oil filter for a filter change!

 

[Sharps40]

Been running it a week and no new issues. The slight shudder continued when just coming to a stop, but thats been there since we got it 30k miles back. Checked the oil and it was a quart low so drained the pan and no strawberry milkshake. Topped it off with Global and a bottle of Lube Guard Red. First run out the shudder is about gone and its shifting smoother. I think it'll be okay untill i can get the calsonic radiator out and a new one in place.

 

[Sharps40]

It would seem that transmission shudder ain't always trasmission shudder. Noted a bit of shudder idling down at stop lights in gear and the idle hovered low around 500 rpm. Seemed a bit low so dropped in a can of fuel injector cleaner and no help. So, looked in the throttle body.....good gosh what a mess.....like my granddaughters bathroom. It seems, Hoppes 9 is a good multipurpose cleaner. A few drops on a patch had the inside spiffy and the butterfly edges shining in no time. Wiped it dry, let it air out and fired it up. Good smooth idle at 750 in gear where it should be and ... no more shudder! Learning stuff every day on these new cars.