auto transmission fluid leak

[smithjw]

I have read just about every post on transmission fluid leaks, but I have not seen one that describes mine. My 81 developed a leak and upon investigation, I found that it mostly leaks while the engine is running and system is under pressure. The problem is, I found the leak, but I don't know what this part is or what it does. Maybe if I describe it, someone else can say what it is.

If I am under the car, directly below the firewall and just to the right (passenger side) of center, there is a cylindrical shaped metal object mounted to the underside of the car. This cylinder has 3 connections on it coming out of the bottom. One is a red hose, one is a black hose, and the third appears to be a cable like a speedometer type cable that connects to a brass 90 degree fitting. It is this fitting that is leaking the red fluid which I assume is transmission fluid. Running just past this fitting are the 2 steel lines that carry fluid from the transmission to the cooler in the front of the car. Those 2 steel lines actually come into contact with the cable just after the fitting. I thought that they may have frayed the cable and that was causing a leak, but after close inspection, the cable is alright, but I guess it puts a little pressure on the fitting and that is where it leaks. Anybody have any idea what this is? There is a nut just before the fitting, but I cant get it to loosen or tighten. I think there must be an O ring inside the fitting that has deteriorated. Maybe this is not a cable. I only presumed that because the casing on it is that spiral steel type that you find covering a speedometer cable. I looked all through my shop manual and did not see anything that looked like or described what this is. Thanks for any help on this one.

Jeff

 

[cheeseral]

cable

This kinda sounds like the TV (kick down) cable that's connected to the throttle cable but right now I can't think of how that connects to the trans. Do you have the original TH350 in the car? If so that would be my guess, if I have time tonight I'll take a look at mine and let ya know what I find.

Chuck

 

[cntrhub]

Take brake cleaner spray and clean the troubled area. Make sure it is oil free, and dry. Have someone start the car and you under, to see exactly when the leak begins to form. This way, you can pinpoint the exact location. Always try to look directly above the leak, just to make sure it's not coming from a higher position. Since you have so many connections to this one area, you should be able to eliminate some of these connections. If it's from on of the oil cooler lines, then yes, you will need a specially made wrench that slips over the line and covers more area on the hose fitting. You might strip the hex heads using a simple open end wrench. Since the oil seems to leak under pressure, I would concentrate on either the cooler lines or the modulator with the hose fittings.

 

[smithjw]

I have already pinpointed the leak. What I don't know is what this thing is. It is not the lines leading to the cooler. What I said was that the lines to the cooler pass right by where the leak is. The lines come in contact with what looks like a cable that has a fitting attached. The leak is here, but I don't know what this is. It is about the only thing on the car that I can't identify. I guess I need to trace where these things lead to to figure out what it is. I keep wondering how this cylinder thing gets filled with tran fluid. It's not connected to the transmission that I can see. If the red and black hoses lead to the cooler, then it might possibly be an external filter for the cooler?

Cheeseral: I believe it is the original TH350.

 

[smithjw]

OK. I confess. I must be an idiot. I must be very dis-oriented while under the car. I wasn't actually under the firewall (thanks to my 14 yr old son for pointing that out). I am actually even with the front wheels, which are toward the front of the engine. I traced the lines and have determined that this is the....(drum roll)...fuel pump. One line in from tank, one line out to tank, and the third line is the actual fuel line to the carb. This line has a special casing protecting it and that is what looked like a cable cover. It's actually a spiral metal covering protecting the line from rupture.

Now, the fuel pump can not be leaking trans fluid, so I was also wrong about that. Back to the 2 metal lines that run from the tranny to the tranny cooler at the front of the car. As I said earlier, these lines were touching the fuel line casing and actually rubbing on it. Although I can't see any rupture, it has to be leaking there when under pressure. It then gets on the fuel line casing and makes it look like the leak is there. I suppose I should get new steel lines to replace these, but first I am going to try and see if some POR-15 painted on will stop any leaking. And boy do I feel stupid for not knowing that was the fuel pump. DOH!

 

[Nut]

Jeff.... don't sweat it. Leaks are one of the hardest things to mpin point with the possible exception of squeaks. Anyway, your patience paid off. Instead of running and jumping on your first analysis, you took your time, and advice from fellow L81 owners and found the real problem. Remember, there are no dumb questions.... ever. That's what your Corvette (and L81) friends are for. Glad you have a solution to your problem.

Good luck and let us know how the fix worked.

............ Nut

 

[Richard Cooper]

Hello Smithjw,
My name is Richard Cooper and I live in New Paltz, New York. I see from your post that you are in Modina, if you want some help let me know you can bring your vette over here and together we will find your problem. I also have a 1981 coupe.
I have replaced my body mounts, calipers, rear main seal, valve stem seals, power steering control valve, computer and much more so I have some experience with the 81.
Let me know, my e-mail address is rcooper1@hvc.rr.com
We live on South Ohioville Road.

 

[smithjw]

Richard, I'd like to stop by sometime and see your vette. Do you show it? I saw a white 81 at a car show in the town park for Plattekill Day once that I think was from New Paltz.

Anyway, for the meantime. I think my POR-15 patch on the steel transmission cooler lines is holding. No more leaks. Thanks everyone for the help and encouragement.

 

[Richard Cooper]

Smithjw, that was my vette and yes I do show it whenever possible. We hav a car show every saturday night at the New Paltz fire house. It starts at 5 PM and lasts till around 8:30-9:00 PM
I live right next to The Villa Cusa on South Ohioville Road. There is a sign hanging out in the front that says The Coopers, thats me. I am always out in the yard on the weekends so stop by whenever.