| Pilotron |
Has anyone ever experienced transmission fluid oozing right through the walls of the transmission's aluminum housing? If I hadn't seen it myself I wouldn't believe it, but I have spent hours laying under my Pilot to confirm the situation.
Using mirrors I inspected all parts of the transmission where one might normally expect a leak. I have definitely ruled out seals, gaskets, threaded items, etc. I verified the leak by repeatedly testing: I carefully cleaned the suspect area with solvent, dried it, and watched it slowly shine up with fluid. It usually takes a warm transmission and about 15 min. to appear. The seepage is on the side of the transmission, and it's not visible by looking straight up from under the vehicle.
If I don't clean it up, it eventually migrates down, developing a film on the nearby flanges and bottom of the transmission. Finally, it collects on a low point of the transmission as a red droplet.
I don't know when this started (it could have been from day 1) because the leak is so small that I only get a couple of tiny drops per week on my garage floor. Since part of my garage floor is covered with dark indoor/outdoor carpet I never saw this until recently.
Also, when the car is driven, any suspended droplets are wind-whipped backwards producing almost undetectable spots on the undercarriage further back on the vehicle. One can't tell they are transmission fluid until wiping them up with a light colored cloth.
We haven't driven the Pilot very much since we bought it. It's only got 5000 miles on it. I thought it would be useful to get your opinions and advice before I took the car into the dealer.
Excerpt from Pg. 14-230 of the Pilot 2004 Service Manual
Transmission Housing--Shaft Assembly and Housing Installation: |
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| Pilotron |
| Overview of Area When Dry: |
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| Pilotron |
| Close-Up of Area When Dry: |
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| Pilotron |
| Close-Up of Area When Wet: |
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| Pilotron |
| Overview of Area When Wet: |
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| Pilotron |
(continued)
Has anyone ever seen this kind of thing before? It must be a problem with the aluminum casting process, but what would the structural implications be? The "flanges" that border the leak are actually strengthening ribs.
Is the only proper solution to replace the transmission, or can something be welded in place? (It seems highly unlikely to me, but thought I would ask.)
If the problem isn't structural, would sealing it off by using some high-tech adhesive make sense or be advisable?
Thanks for your inputs. |
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| PILOTinginCO |
Well... I agree with you... this is weird!!!!
I would almost think there is a metal problem with the casting of the transmission and that it would likely need to be replaced.
In the pictures you supplied, it looks like there are a series of crack-like objects in the metal.
I would be interested in hearing what your dealership/Honda has to say about this one. |
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| cwa107 |
I had a very similiar problem years ago with an '89 Ford Probe (4 cyl/automatic). I took it to shop after shop trying to find one that could diagnose and correct the leak. Although I dried it repeatedly and checked around the seals, it looked like it was coming through the casting itself.
As it turned out, I finally found a decent mechanic who had encountered the problem on his daughter's Probe of that vintage. Apparently, there was a small piece of hose (about 3 inches long) that carried transmission fluid and it was mounted around the top of the transmission with spring clamps at each end. The spring clamps tend to lose tension after a period of time and start to leak. The leak drips and pools at the top of the transmission in an inconspicuous area. After awhile, it runs down the side of the transmission and slowly drips out. For all intents and purposes, it looks like it's coming through the casting, but in reality it's just running around the transmission and pooling until it drips. |
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| Pilotron |
To PILOTinginCO:
It's almost impossible to tell if they are really cracks or not. I tend to doubt it. In looking at all of the cast aluminum pieces (e.g., parts of the bottom of the transmission in my last photo) there are a lot of surface imperfections from the casting process (and this is typical). Many of them look like cracks but aren't. However, the metal can't be really solid and still allow fluid to pass through, so some type of flaw is responsible. Cracks are not ruled out. I'll definitely post what I find out as time goes on.
To cwa107:
Your experience was my first type of thought when I started looking into this. I know how strangely transmission fluid behaves. Consequently I spent hours over, around, and under the vehicle trying to find any hose, connector, seal, or otherwise that could be responsible.
I really hoped it would be something like you describe because then it would be easy to fix. But, I assure you I have been more than thorough. Also, I have really good tools--inspection mirrors, krypton flashlight, halogen work lights. Once I found the spot I have been able to watch the fluid appear before my very eyes. (The photos only do the situation partial justice.) Although the spot is not in the easiest location to deal with, I can see and feel all around it, and have never found anything flowing down from above (or leaking anywhere else for that matter).
However, just so you know that we're on the same page, last week I cleaned the whole side of the transmission very well (which it didn't actually need since it's so new), then I rolled up some absorbant cotton wipes and pressed them into the area between the flanges. Then I sealed the section off with duct tape really well, making it impenetrable. As you can see in the top diagram, this was easy to do because the flanges helped create a natural "box."
After setting this way for a couple of days, I removed the tape. It had no transmission fluid on it anywhere (front or back), but the wipes had a nice oblong stain right where they made contact with the metal.
Still, I appreciate your input and will keep it in mind. |
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| AlH |
| Porous casting, happens all the time with aluminum wheels, casings etc. Had it happen back in 83 with a Chevy Van transmission. GM's fix- clean area really well and cover it with epoxy, something like JB weld. Wonder if Honda will try that or give you a new transmission? I would not let them disassemble it and replace just the leaking casting, either the epoxy fix or a new trans IMHO. |
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| rocky |
quote:
Originally posted by AlH
Porous casting, happens all the time with aluminum wheels, casings etc. Had it happen back in 83 with a Chevy Van transmission. GM's fix- clean area really well and cover it with epoxy, something like JB weld. Wonder if Honda will try that or give you a new transmission? I would not let them disassemble it and replace just the leaking casting, either the epoxy fix or a new trans IMHO.
I agree with this assessment. It happens with many of the Land Rover Aluminum engines. Heard of wheels going porous too. So its possible. |
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| Pilotron |
Thanks for all your input.
To AlH:
It will be interesting to see what the dealer/Honda recommends, but I have no compass about this, meaning I wouldn't know if the sealing-off method would be wise. Perhaps it depends on severity of the problem. I do agree that if sealing-off is not an option then replacing just a bad casting would bother me a great deal.
Did GM's fix to your Chevy van work or did you have subsequent problems? One issue I have is that I intend to keep our Pilot for a long long time.
To xGS:
Very cool idea. Luckily I think I have already found the leak, but I am concerned about my ability to prove it. Also I am worried that where there is one casting flaw there may be another which hasn't shown itself yet.
To rocky:
This is part of what I was hoping to hear. |
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| sfdude |
My Pilot had the exact same issue, in almost the exact same spot last year.
I run a transmission shop, and see this from time to time. It is called case porosity. It is usually caused by voids in the casting.
Mine had 13,000 miles at the time. Dealer ordered and installed new tranmission for me.
Chad |
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| Sportymonk |
| If you want to pursue it yourself some more, lightly sprinkle some talc powder around the transmission leak area and above. Any leak should show up clearly. Do not let it get in the transmission. |
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| AlH |
quote:
Originally posted by Pilotron
Thanks for all your input.
To AlH:
It will be interesting to see what the dealer/Honda recommends, but I have no compass about this, meaning I wouldn't know if the sealing-off method would be wise. Perhaps it depends on severity of the problem. I do agree that if sealing-off is not an option then replacing just a bad casting would bother me a great deal.
Did GM's fix to your Chevy van work or did you have subsequent problems? One issue I have is that I intend to keep our Pilot for a long long time.
Held as long as I owned the van, which I sold at 36,000 miles when they warranty ran out! Had lots of problems with that van. |
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| krygny |
| Bad casting, defective tranny. I'm not one to put the screws to the dealer for knit-picky things like discolored paint or saggy leather, but in this case, the tranny is defective. If you leave it with them to give them a chance to fix the leak, they'll put a band-aid on it and it will work - for now. I wouldn't accept anything less than a factory reconditioned tranny. If the dealer gave me any $hit at all, I wouldn't waste time taking it up the chain of command. |
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| Pilotron |
I appreciate all your responses.
To sfdude:
It's reassuring to know I'm not the only one to have encountered this.
To Sportymonk:
Also a good idea.
To AlH:
I was also the not-so-proud owner of an '80s era GM product and you DON'T want to hear about my experiences with that. There isn't enough disk space on the server.
To krygny:
Yes, band-aid fixes are a real concern, and transmission replacement makes a whole lot of sense. The only downside I can think of is whether the dealer would do a good job on such a major undertaking. I have had some bad experiences in that regard, although not with Honda (so far). |
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| jl_ss |
quote:
Originally posted by Pilotron
I The only downside I can think of is whether the dealer would do a good job on such a major undertaking. I have had some bad experiences in that regard, although not with Honda (so far).
Given Honda/Acura's past tranny problems, most Honda Dealers have a great deal of experience replacing trannies. I wouldn't worry to much about that. |
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