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cruising
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Discussion Starter #1
I was looking over the car on my last oil change and saw this. Im having a leak right at the speedo gear. Is this something simple as an o-ring leaking or not in there tight enough? Wanted to get some opinions before i mess with this. Thanks guys

Zack





 

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Look like is loose you can see the retainer and the bolt is not all the way down!! Oh no i remember that dont go all the way down i guess is a old o ring
 

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cruising
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Discussion Starter #3
Thanks. Do you know any specifics on the size of the oring or part number? This is on my driver and why im asking or i would take the part in and have the oreilys match it.

Zack
 

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Well this is common I worked in a trans shop for a few years. It could be couple of different things.
1. The oring has gotten hard and you can swing buy most trans shops and they will sell you one usually pretty cheap I also recommend putting some clear silicon on like GE window sealant that's what we use to do
2. I also have seen the housing leak around the shaft the speedo gear attaches to. On this part I'm not sure if the inner seal is replaceable like on GMs but you can find plenty of those at a salvage yard. It doesnt have to be mn12 it can be any Ford rear wheel drive close to the year of your car. Just replace the oring on the used unit and use you speedo gear. The speedo gear comes off easily its self explanatory when you see one.
Hope this helps.
 

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Well this is common I worked in a trans shop for a few years. It could be couple of different things.
1. The oring has gotten hard and you can swing buy most trans shops and they will sell you one usually pretty cheap I also recommend putting some clear silicon on like GE window sealant that's what we use to do
2. I also have seen the housing leak around the shaft the speedo gear attaches to. On this part I'm not sure if the inner seal is replaceable like on GMs but you can find plenty of those at a salvage yard. It doesnt have to be mn12 it can be any Ford rear wheel drive close to the year of your car. Just replace the oring on the used unit and use you speedo gear. The speedo gear comes off easily it self explanatory when you see one.
Hope this helps.
,
No o-ring there, just a paper gasket.
 

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I feel like such a noob with this problem but I've replaced the o-ring on the speedo gear twice now with 2 different sizes and the dang thing is still leaking. Is this not a universal part?

It is the aftermarket speedo gear. (I think 21 tooth, purple gear)
 

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Maybe the new o-ring got damaged on install? I'd coat it with vaseline first. But if you're playing around with different sizes, that's gotta be the problem right there.
 

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try a new o ring with black rtv solicon.It might be the speed sensor it self leaking run to napa I wouldn't use one from autozone or advance pull out the old one and there is a e clip that holds the gear on to the speed sensor can pull that off with a pocket screw driver pull the gear off slide it onto the speed sensor and put it back into tail housing with a new oring and some silicon
 

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50 years of Mercury Cougar 1967/2017
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1,270 Posts
I have found when the trans is over filled, there is a leak from various points.
Example, I had a deep pan installed, now there was a leak around the dip stick tube.The dip stick showed full.

In reality, due to parts that were swapped, the trans. was actually over filled.

The same thing happened to my 96 cougar, swapped a converter, filled the trans., had a leak.
Due to more swapped parts, pan, filter, converter, the trans. was over filled.

Moral, the dipstick does not always read correctly when parts are changed.

Just use enough transmission fluid thats needed to make the car move, then add
1/2 a quart more.
Then pay attention to when you are making hard turns, on throttle for slippage.

Though there shouldn't be any. This is not a gurantee that there isn't an actual leak.
 

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would go with the size you need don't go bigger it might get damaged on the way in and leak...just go to a local trans shop and ask the for the right o ring if you cant find one pm me your address I got about 15 of them on my tool box and if I dig thru the shop probley find about 200 more..
 

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cruising
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Discussion Starter #12
I have found when the trans is over filled, there is a leak from various points.
Example, I had a deep pan installed, now there was a leak around the dip stick tube.The dip stick showed full.

In reality, due to parts that were swapped, the trans. was actually over filled.

The same thing happened to my 96 cougar, swapped a converter, filled the trans., had a leak.
Due to more swapped parts, pan, filter, converter, the trans. was over filled.

Moral, the dipstick does not always read correctly when parts are changed.

Just use enough transmission fluid thats needed to make the car move, then add
1/2 a quart more.
Then pay attention to when you are making hard turns, on throttle for slippage.

Though there shouldn't be any. This is not a gurantee that there isn't an actual leak.
I had a deep pan on mine so what you were saying about the reading on the dipstick could hold true to the leaking.

Zack
 

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if it was over full it would either come out of breather on top of trans or front seal ...ever since I put on my trans cooler I run mine 1 qt. plus over with out a problem and every trans I install...about 8 a week I always over full them atleast a pint to a qt. with out any problems I over full them because if the costumer sees a leak he can get it back to the shop before he does any damage from running it low and it does help with keeping the trans cooler
 
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