I am contemplating updating my transmission lines and cooler in my 2005 DB9. I am lucky enough to have a nice 4 post lift, so access shouldn't be a problem but I keep reading that the replacement hard lines cannot be installed without lifting the engine from its mounts slightly. Is it possible to thread them through without such a drastic maneuver?
Now I know a few people are going to feint here ..... but couldn't a person snip the hard lines and install a separate sleeve joint at that point? I live in rural North Dakota, so I'm sure someone around here who works with hydraulics, could fabricate a suitable hose setup for me. What do you think? (......pulls on flameproof coveralls and ear-defenders).....
While I'm in a heretic mood ...... Couldn't the entire run from the cooler back to the thermostatic valve, be replaced with a pair of resilient hydraulic hoses. I'm thinking it wouldn't cost me $920 either!

 

Nothing magical about the current lines. Need to decide max psi/#cycles/temperature. You could figure that out by looking at the line once you remove it. Check out Parker's GlobalCore product line... That's what I use.

 

My local mechanic sent my leaking transmission cooler lines out to a hydraulics shop to have new ferules brazed on with new hose segments. It still required removal of the hard-lines, but it was much less expensive than ordering new ones.

 

OK... I got busy this afternoon and wrestled the underbody panels off. I was intrigued to see just how much "stuff" there would be on the upper surface of the front panel..... I had watched "Aston 1936" taking off his panels in one of his excellent videos and marveled at how clean everything seemed to be. Yeah ... not mine! I seem to have a little of everything on mine, oil, transmission fluid, antifreeze, dead bugs, gravel and a bunch of .....gunk.


Yikes! That's a lot of crud!
So then I took a look at the transmission cooler lines at the front, to see if they looked fragile. Well, they sure looked 'wet.' I have to believe that they have been leaking fluid for some time. What do you think?

Lines don't look good to me....?

..... and could these be the original lines? I'm not sure how to tell... can you help?


Does the labeling help to identify their age?


I'm pretty sure I'm going to put a new cooler in and then convert the "hard" lines to a braided flexible system. AM4884 seemed to think that was a doable operation and I would take it all the way back to the thermostatic valve, just ahead of the transmission. There are plenty of mounting points that I could use from the hard lines to secure the flexible lines and there would be less joints to leak or work loose... Good idea, or not?

 

FWIW, my pans looked worse, but then the PO didn't do much but trash the motor... I used Goof Off and a green steel pad and they cleaned up really nicely.

Given how little they appear to be leaking, I'd be very tempted to clean them, and leave them be. But I understand why you want to replace them. My only observation is that a hydraulic line shop could build you new lines. And now that wheat season is over they are looking for something to do...

 

The original older style look like this:





Here's a shot showing the original (upper with aftermarket clamp) and the updated OEM (lower):


The previous owner only replaced one set of lines so I had both types. Of course, the one that wasn't replaced started leaking shortly after we brought her home.

 

That looks more like a front cover leaking engine oil vs the lines. Can you post a picture of the transmission oil cooler in front it looks like you have the newer hoses.

 

i agree that it looks like a cover leak. Tell tail is the oil collecting on the front pan bolt head which builds to a point and then drops off and then starts to collect again, etc.

 

So on my DB9, these hose connectors

are not replaceable I assume. They appear to be brazed/welded onto the 'hard' lines and then the rubber hose portion is crimped inside? I want to replace the rubber sections of the entire transmission cooler lines, all the way back to the thermostatic valve, but it looks like the only way to do that would be to physically cut the factory fittings off the end of the hard lines and replace them with after-market connectors? Is that true?
If I do end up replacing all the lines with new factory lines, what is the procedure for raising the engine enough to wiggle the hard lines out of their location? Do I just release the nuts under the engine mounts and start jacking on the sump? ... gulp....

 

My hydraulic line repair man carefully pulled the factory connector back and recrimped it to new hose. As for getting the line out, I will just say that jacking up on the sump is "fraught with danger". I have used wooden blocks across the back of it to hold it in place, but only with the front mounts supporting the front of the motor. You can't really raise the motor, about all you can do is hold it in place given the torque tube/transmission locking the rear in place.

 

So in the process of disassembling my transmission, I encountered the little black, plastic box that is located above and to the left of the filler plug.

In the picture below, the filler plug is circled, but the component I'm interested in, is mounted above it, to the left.


The little black box known as the gearbox capacitor

What the heck is this component's function? It is listed as an "RFI capacitor" in my workshop manual..... but what is its purpose? There are several wires in a harness that share a feed to the transmission controller, and they enter the unit on one side ....and then there are two tiny wires that loop back into the unit from the other side!
I am thinking it is "sensor" related, but my knowledge of electronics is very limited, so I was hoping someone could clue me in as to what it is.

If it is a sensor, what does it sense?

 

"RFI" is Radio Frequency Interference. Apparently there are some sensors in the transmission and there is a control signal that feeds back to the tranny computer. The designers are concerned that there could be RF emissions which could cause the computer to think that the signal was switching state rapidily, or more likely they wanted to make sure it never happened. Switching state could cause the car to think it is shifting gears, or needs to shift gears. Either way they want a relatively slow change of value.

The RFI Capacitor is a small capacitor placed across the sensor lines to provide a stable signal (get rid of the RF noise). It does this by acting like a small battery that needs to be charged/discharged. It has high resistance at DC, low resistance at high frequency. The upshot of this is that high RF signals are muted, the signal you want passes easily.

 

Wow! That's a fabulous description... but now I'm even more boggled at how many sensors a modern vehicle has..... I think I'm glad I don't have a pacemaker! Thanks AM4884