I by-passed my in radiator tranny cooler

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BamaRed
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Postby BamaRed » Thu Apr 01, 2010 6:31 am

2006R51MD wrote:I want to do this but I would assume that this would void any warranty...correct?
If you have an issue, just take and reverse the procedure before you take it into the stealer.

No Harm, No Foul...

JMHO


LittleStevie
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Postby LittleStevie » Sat Apr 03, 2010 4:46 pm

I have to say, I ignored this thread for a long time because this sounded like a dumb thing to do. Engineers generally have a good reason for designing something the way they do and, unless you fully know the design basis, then you shouldn't be monkeying with it. As home mechanics and end users, we just don't have access to the technical design data to make this kind of call.

Nonetheless, today I joined the crowd, bypassing the cooler with the hose swap method. What changed my mind? That a little pinhole in the cooler could turn my transmission into a $4,000 strawberry milkshake blender. I guess I decided that I'm more comfortable with my transmission not running at the optimal temp than the risk of catastrophic failure. Hopefully that's the only risk...I'm still uneasy about doing this, but I'll sleep better not worrying about engine coolant contamination.

By the way, for $11 at Nissan I bought a can of their Transmission Cooler Cleaner P/N 999MP-AM006. Works very nicely, comes with an adapter that plugs right into the rubber hose left on the radiator cooler. In about 20 seconds it had blown out all of the old fluid and clean solvent was coming out. Nice insurance to avoid contaminating the engine coolant if the cooler were to leak.

Thanks for everyone's pioneering spirit in this and eventually getting me to come around.

ravrunner
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Postby ravrunner » Tue Apr 13, 2010 9:27 am

Guys,

I just finished reading all 10 pages of the thread and maybe I am to late to do this on my 05 pathfinder with 64K miles.

3 days ago at a stop light my service engine light came on and noticed some loss of power on the car at the start of accerleration, GUESS WHAT....

Dam radiator failed and mixed the coolant with the trans fluid, sure enough the stealer said I need a radiator ($550) and new transmission ($6000) my jaw dropped....

Luckly enough the tech guy showed me the trans dip stick and uncapped the radiator and it was just like some of you describe "strawberry milky fluid" .
Now, he told me I can still save the trans by changing the radiator and flushing the transmission about 2 or three times until I see red fluid. This would run me $1100 at the stealership! Am I to late & and F***Ked?

I drove the car back home and transmission shifts normal but as of now I am not going to drive it until I do all of this.

Do you guys think the transmission will go bad even after I get all the contamination fluid out? I will flush both systems as well. let me know your thoughts as I have gotten good info on here and will be doing this bypass when I put in the new radiator!!
Thanks!

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eieio
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Postby eieio » Tue Apr 13, 2010 10:08 am

What a bummer............
Those are tough questions to answer :(
If you decide to do the flushes, my instinct would be to get them done really ASAP, because the longer there is moisture in the transmission, the more chance there is for damage to occur.
There is a much better chance of saving it if you do it right away!
You could do the "by-pass" on the existing radiator before the transmission flushes & keep it, rather than replace it. :wink:
If the flushes seem to work, it might be a good idea to do another one or two in the very near future, just to be sure that all the coolant is purged out of the system.
It might be OK to hold off on the coolant flush right away if you want to do a "wait & see" after the transmission flushes.
I doubt that a little oil in your coolant would do any harm for a short time.
But obviously, that's a decision you'll have to make :wink:
Also, if you have a reputable independent shop, you might check & see how much the flush(es) would cost there.
Just be sure that the proper correct recommended fluids are used.

ravrunner
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Postby ravrunner » Tue Apr 13, 2010 10:28 am

Dryart,
thanks for the recommendations, i think the radiator will be best o replace because it looked pretty bad when the tech guy took off the cap, no sighns of green at all, almost pure white strawberry substance.

As for the flushes, then I am going to do it right away, i was waiting on recieveing the new radiator, but i guess they can start flushing the trans in the meanwhile.

I want to do the coolant flush since it seemed pretty bad in the radiator already.

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eieio
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Postby eieio » Tue Apr 13, 2010 10:41 am

sounds like a bad case, that's a shame.........
wish you the best, and please keep us posted on the progress

ravrunner
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Postby ravrunner » Wed Apr 14, 2010 6:15 am

Does anyone one know or recommend I change the transmission filter after I do the flush?

I looked for the part but couldnt find one.

And I should also use NIS ATF MATIC-S 999MP-MTS00P fluid?

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SilverGhost
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Postby SilverGhost » Wed Apr 14, 2010 11:06 am

Mine's done! I was becoming paranoid about the prospect of cooking my transmission :shock: , so I visited a familiar independent mechanic and paid him $50 to make the change. Yeah, I coulda done it, except I didn't have any jack stands to hold it in the air while I crawled around under the thing. Money well spent, IMO!!

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pawjr74
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Postby pawjr74 » Wed Apr 14, 2010 11:19 am

Does the Pathfinder have any warning light if the tranmission is reaching an excessivly hot temp?

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SilverGhost
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Postby SilverGhost » Wed Apr 14, 2010 12:17 pm

pawjr74 wrote:Does the Pathfinder have any warning light if the tranmission is reaching an excessivly hot temp?
My '06 LE has a warning indicator. But, if you're referring to the tranny overheating as a result of coolant contamination, I'm guessing that the damage would have already been done by the time the light comes on. Of all the folks who have had this problem, I don't recall any of them being alerted in advance about overheating.

bellwilliam
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Postby bellwilliam » Wed Apr 14, 2010 12:45 pm

I think there is a misconception here that by doing the bypass, you might overheat the transmission. it is the other way around. w/o bypass, transmission warm up FASTER.

if you really are concerned about heat. just install another transmission fluid cooler, it is pretty simple. not much to it. and cost may be 1 hour of labor and $100 for parts.

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pawjr74
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Postby pawjr74 » Wed Apr 14, 2010 1:07 pm

I was wondering if it had the excessive heat warning indicator that way if I did the bypass I could make sure that the transmission never got too hot. I'm on the fence right now and not sure which way to jump. If there was at least a warning that the trans was reaching a high temp than I could re-asses the situation. I'm a little nervous living out here in the desert. I also go to California quite a bit and that is a 6 hour drive across the desert.

Other (Non Nissan) internet posts suggest excessive heat up of the trans when the rad trans cooler is bypassed.

kramer
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Postby kramer » Wed Apr 14, 2010 1:58 pm

SilverGhost wrote:Mine's done! I was becoming paranoid about the prospect of cooking my transmission :shock: , so I visited a familiar independent mechanic and paid him $50 to make the change. Yeah, I coulda done it, except I didn't have any jack stands to hold it in the air while I crawled around under the thing. Money well spent, IMO!!
Completely unnecessary to jack it up... everyting is perfectly accessible without lifting, or at least it was on mine!

Oh well, $50 isn't bad to let someone else do it I guess.

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SilverGhost
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Postby SilverGhost » Wed Apr 14, 2010 2:20 pm

kramer wrote: Completely unnecessary to jack it up... everyting is perfectly accessible without lifting, or at least it was on mine!

Oh well, $50 isn't bad to let someone else do it I guess.
My back problems, and my size make it pretty difficult to navigate under the thing without jacking it up. Everything stayed clean, particularly my driveway. I even had him blow air through the internal cooler just to avoid any future leakage problem. He also cleaned and wiped down all the oil splatters from underneath. I don't regret the price in the least.

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eieio
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Postby eieio » Wed Apr 14, 2010 2:25 pm

pawjr74 wrote:I was wondering if it had the excessive heat warning indicator that way if I did the bypass I could make sure that the transmission never got too hot. I'm on the fence right now and not sure which way to jump. If there was at least a warning that the trans was reaching a high temp than I could re-asses the situation. I'm a little nervous living out here in the desert. I also go to California quite a bit and that is a 6 hour drive across the desert.

Other (Non Nissan) internet posts suggest excessive heat up of the trans when the rad trans cooler is bypassed.


Sitting on that fence could become dangerous . :shock:
Seems to me that there wouldn't be much cooling going on of fluid circulating through a radiator full of hot coolant .
I'm more a believer that the transmission "cooler" inside the radiator is more of a transmission oil "warmer" to get the trans oil up to operating temperature more quickly, for very cold climatic conditions.
I wish someone who really knows about this feature would share their knowledge about it.
It would set a lot of minds at ease. 8)
Regarding the suggestions on other posts that the by-pass could cause excessive heat build up, many people do not know that our Pathfinders have an external transmission cooler on them!
If one wanted to, an additional one could be added.


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