I was hesitant with installing an ATF Cooler for the following reasons...But, after reading this thread I talked myself out of adding the trans cooler as an option. This just isn't right.
Interesting read, if you or anyone else has time.Mine makes noise after warming up by driving 5-6 miles. Does not make noise before that. As the tranny warms up the noise gets louder.....The noise is only made in D on the 7-8 upshift under light acceleration. That shift usually occurs around 50 mph. The noise has been described as sort of a rumble strip type noise, a buzzing, or a coiled spring unwinding. Noise can also be made at will by using the paddle shifters to make the same 7-8 upshift. If the PP is going too slow you will not be able to make it shift from 7-8. You will see 8 flash then the display returns to 7. There is a video posted here in this discussion that shows when the noise occurs and if your sound is turned up high can be heard. In my PP you can also feel a slight shudder coming from the front when the noise happens. As mentioned previously, Honda says this noise is normal due to the dog clutch in the 9 speed engaging at the 4-5 and 7-8 shift. No one has explained to me why it does not make any noise at the 4-5 shift nor why the noise is amplified by the trans cooler. Please let us all know if you, indeed, can't get your to make the noise under the same conditions. That would be very interesting. Thank you
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The instructions do say to inspect and adjust the fluid level. You would think the Honda technicians would know to do this anyway when installing the cooler. You would also think if a vehicle was brought in with the complaint of transmission noise the fluid level would be checked. Finally you would think that a Honda rep wouldn’t say the noise is normal if it in fact wasn’t normal. All that being said, I would not trust any of the above I would double check the fluid level myself.. if not qualified then make a request for the dealership to do so.
That drawing in that article is very misleading. The dog clutches in the ZF don't look anything like that. The article itself is ok.Interesting read, if you or anyone else has time.
Sounds logical that stiffer lines would fix the issue.Well that video explains some things raises a new hypothesis. The 7-8 shift is the release of a dog, not an engagement. And...I bet it's not synced like it is when engaged. It releases under load to make the 7-8 shift. And...the oil pressure to release it comes in the shaft through a port at the far end. The symptoms here hint at the dog gear not disengaging quickly and cleanly, right? The fluid/oil not pushing hard enough. What might cause low oil pressure pushing that dog back out...when having a trans cooler?
Hoses to the trans cooler. Not being rigid enough like brake lines. Absorbing some of the brief pressure surge when the box is trying to push out the loaded dog gear. Or just the increased oil volume due to the cooler. But the cooler is causing lower oil pressure in the gearbox somehow.
Just a guess. Maybe a motivated person will try braided hoses on a trans cooler.