Small transmission leak
Thread Starter
Instructor
Joined: Jul 2017
Posts: 217
Likes: 21
Small transmission leak
I've got an 81 automatic. When it sits for a few hours there are a couple of drops of transmission fluid under the car, not real sure where it's coming from. My initial guess is maybe from the speedo cable since the speedo has been off by 5mph since I got it. How should I approach this? Just pull the cable out of the trans and look at / change the gear? Maybe clean everything off first and check it to see if I can see where it's coming from? I'm getting ready to sell it and don't want to have to add transmission leak to the list of things. (Don't worry, i'm buying another C3 soon!) Also, when I pull the speedo cable, will fluid pour out?
Last edited by tehjrow; Aug 7, 2018 at 07:06 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
No, when you pull the cable, no fluid. There is a "O" ring on the speedo cable bullet piece you can replace.
Other leaks could be:
Fill tube at the bottom where it enters the casing. "O" ring there also.
Tailshaft housing rear seal. Requires driveshaft removal.
Tailshaft housing body gasket. Requires driveshaft removal and tailshaft housing removal .
The pan itself, gasket changing, install new filter too.
Shifter cable location where it enters the casing.
Other leaks could be:
Fill tube at the bottom where it enters the casing. "O" ring there also.
Tailshaft housing rear seal. Requires driveshaft removal.
Tailshaft housing body gasket. Requires driveshaft removal and tailshaft housing removal .
The pan itself, gasket changing, install new filter too.
Shifter cable location where it enters the casing.
Last edited by HeadsU.P.; Aug 7, 2018 at 08:08 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
To find the source of such a leak you really need to clean off all the areas of possible leakage, then start the engine and watch for seepage. Once a leak starts, the fluid can run down surfaces so that you don't know where it really starts. Clean surfaces of all oil/dirt/etc, then watch for point[s] of initiation. Parts stores may sell a spray powder that you put on clean surfaces. When that powder gets damp, it shows up like a 'sore thumb'. There are also dyes that you can place into oil systems. A UV penlight will cause any leaks to illuminate in a darkened area.
Find the specific sources of leakage, then repair them. If you find that the trans is weeping oil out the inspection cover drain hole, the converter seals/bushing are worn to where that will only get worse with more use. Most folks wait until it really bothers them...then they get the trans rebuilt. That decision is left to the owner.
Find the specific sources of leakage, then repair them. If you find that the trans is weeping oil out the inspection cover drain hole, the converter seals/bushing are worn to where that will only get worse with more use. Most folks wait until it really bothers them...then they get the trans rebuilt. That decision is left to the owner.
