LT1 Rocker

I am getting jerked around by the outfit that I purchased a rebuilt 700R4 Transmission from.

I had a local certified mechanic install the transmission about a year ago and have had leakage problems every since caused by the pan gaskets blowing out.

It appears that pressure is building up inside the trasnsmission and blowing the pan gasket at it narrowest point on the front right hand side of the pan, consistently in the same spot.

The last time around we were dealing with a new pan with the flatness of the pan and rail checked.

There was the familiar fluid puddle on the garage floor in the morning.

The rebuilder does not agree with the mechanics theory that the transmission vent tube may be plugged causing excessive internal pressure. I understand the the transmission has to be dropped to access the tube in a Vette.

I can hear a hissing (air escaping) type noise when slowly accelerating and at one point fluid was trying to fill the dipstick tube and made it appear to be over filled.

No one likes being the pivot man in a circle jerk but that is my current position. Very frustrated after a year of this crap and still paying to determine if a warrantied transmission is at fault or if the installer is at fault. In the mean time the situation is emptying my pockets.

Has anyone had a similar problem?

Thanks

0Paul Ruggeri

Here in California we have a Bureau of Automotive Repair, if you have something simular in NY, I'd give them a call.

Hooked on Vettes

You replaced the pan and gasket and that did not solve the problem. It
leaks from the same area.

Assuming a good quality rubber or cork gasket is being used and the pan bolts
are torqued to 8 ft. lbs. A common problem is a leak from the dipstick tube
rubber grommet or the TV cable rubber grommet where they enter the transmission.
Both are on the passenger side of the transmission.

Depending on the size of the leak, the symptom can be as you described.
You may only see the leak after driving the car and letting it sit over night.

Take some paper towel or toilet paper and tape it up above the transmission
pan rail area on the right side of the transmission and above the area
where you say the leak is.

You'll easily be able to see if the leak is coming from above the pan area.
The paper towel will soak up any leaking transmission fluid.

The air hissing noise sounds like an exhaust leak.

LT1 Rocker

Thanks for the suggestions.

The last time around I added dye and the only place where it showed up under UV light was at and under the area where the pan gasket failed. No leaks from above that area.

This area is the narrowest on the gasket due to a clearance design of the pan for an internal component.

My garage floor is well lubricated!

383vett

What does a pivot man in a circle jerk do anyway? Seriously, if the pan rail is flat, there should be no problem sealing the pan. It would take a whole lot of pressure to blow out a pan gasket. I would think oil would be lost out the front seal before a pan gasket blew. None the less, the whole transmission doesn't have to be dropped to access the vent tube. The cbeam needs to be pushed backwards and the back of the tranny can be dropped the 5" or so needed to reach above the tranny with your arm. I guess a wire can be used to "root canal" the tube (I'm a dentist) and to make sure it's clear. I would try another pan, or tap the existing pan to make the rail perfectly straight and flat and try again. Check the cooler line fittings for leakage and the front seal. If there is a leak at either of these areas, the fluid will run down the front of the pan making it appear like a gasket leak. Willie

Pete K

I wish I had something useful to add. I have been screwing around with these transmissions for quite a while, and I have never run across the pan being under pressure.