I have a newly rebuilt 400 automatic transmission in my 67 GTO. When I drive it then park it about a half a quart of transmission fluid leaks out from the vacuum regulator attached to the side. It has a new o-ring and I slightly bent the metal prong that holds it snugly up against the side of the transmission. Why does it continue to leak from that location? Is there too much pressure building up? Thanks.

I have a newly rebuilt 400 automatic transmission in my 67 GTO. When I drive it then park it about a half a quart of transmission fluid leaks out from the vacuum regulator attached to the side. It has a new o-ring and I slightly bent the metal prong that holds it snugly up against the side of the transmission. Why does it continue to leak from that location? Is there too much pressure building up? Thanks.

Where does the fluid leak from??

If it has ti*s or tires, it's gonna cost ya!

Make sure that the slightly bent metal retainer bracket is placing tension on the modulator to hold it in. It is possible to install these backwards.

Also, you might want to make sure that your dipstick tube is fully inserted, not bent, and that the oring is not cooked/ripped/etc. A leak at the insertion point for the tube usually dribbles down all over the modulator and looks like the modulator was the source of the leak. Unfortunately, it sucks to pull the tube because it is probably bracketed on a bellhousing bolt nicely located near the heater/AC box.

"...ridge reamer and ring compressor? Do they have tools like that?"

Also, I forgot to mention that the cooler lines also tap into the case in this same general area. Those could also be a source.

"...ridge reamer and ring compressor? Do they have tools like that?"

boboh1, If you are sure that the leak is from the vacume modulator at the shaft area, remove it and check to be sure that there is not a second O-ring inside housing.As mentioned in the earlier post, check the spring clip direction. If modulator checks good and there are no extra O-Rings, clean the shaft of the modulator and the housing. Apply a small amount of form a gasket around the seal area. Install it and let it dry for about 1 hour.

My TH400 is leaking from the cooler line connectors, your's may be too. Wipe everything dry, then start the car and let it run while you or a buddy check underneath to see where the fluid starts weeping out. Creative use of sealing products will probably fix it. http://forums.performanceyears.com/g.../icon_wink.gif

If it has ti*s or tires, it's gonna cost ya!