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Username Post: 700R Transmission Fluid Leak        (Topic#241077)
Forum Newbie
Posts: 1

Reg: 04-30-10
04-30-10 02:36 AM - Post#1907303    

I had a 700R transmission put in my 1957 Chevy, with a 350 engine. After storing the vehicle for the winter, I have a huge puddle of tranny fluid under the car. Can anyone tell me how to stop this leaking? I do know the guy who rebuilt the 700R used a cork gasket, could this be the problem? Should I replace with a neoprene gasket?


Cruiserdog - Michigan


Bruces 57 
Frequent Contributor
Posts: 2394

Reg: 01-03-07
04-30-10 03:25 AM - Post#1907309    
    In response to cruiserdog

I have the same set up. I have had leaks out the tailshaft, the pan gasket, ect, ect, ect!
First, you must determine just exactly where it is leaking from. Next, if it is a pan gasket, one of the better ones can be found at the chevy dealer. If it is leaking from the front seal, good luck! gotta pull the trans and put in a new front seal.
But, first before the horror story starts, determine where the fluid is coming from!


Senior Member
Posts: 508

Loc: Caney, Ks, USA
Reg: 10-28-01
04-30-10 06:35 AM - Post#1907376    
    In response to Bruces 57

Check the dipstick tube o-ring and the cable that goes up to the carburator. It has a special seal that could be leaking.
I had pretty much the same problem and it was the dipstick.


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Reg: 10-28-08
04-30-10 09:13 AM - Post#1907440    
    In response to toms57

after sitting all winter..i have had torque converters empty down...which overfills the trans...forcing fluid out the vent etc

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"11th Year" Platinum Supporting Member
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04-30-10 10:34 AM - Post#1907475    
    In response to cruiserdog

Find the source of the leaks first, then figure out the action plan afterwards.

Went thru this process with my 2004r recently. Ended up having to replace the pump to torque converter hub bushing. The front seal wouldn't hold it back, but the source was the pump bushing.

Leaking just from sitting? Could be a few things, probably NOT the bushing though.

Use some brake cleaner spray to clean it all up, then start it up and let it idle for a few minutes then shut it off and see if it's obvious.

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Reg: 03-28-02
04-30-10 11:38 AM - Post#1907518    
    In response to WagonCrazy

After sitting, the leak can come from several places as the torque convertor drains fluid back into the case.

Fill tube O'ring, shift shaft seal, speedometer bullet O'ring, or speedometer driven gear seal.

Home.., is where dog hair sticks to everything but the dog.


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