C4 pan leak

[GT350AUS]

I've constantly got a leak from the pan gasket.

I've removed the pan and straightened the ridge along the bolt holes, refitted a cork gasket and torqued the bolts to 15 foot pounds.

The leak continues.

I've don't it 3 times and still leaks.

I welcome suggestions as to what can fix this problem.

[NC TRACKRAT]

"I feel your pain"...and so does everyone else with a C4.  The pan flange has to be as flat as a gauge plate.  Best solution to try is a new pan.  Don't go so high on your torque and do it in stages, criss-crossing as you torque, just like you would on a valve cover.  Some may suggest a synthetic material gasket.  Others say cork is best.

[Royce Peterson]

I have not had trouble with C4 pan leaks. Often the O - ring on the dipstick tube leaks, resulting in the appearance of a pan leak. Make sure that is not your problem. Fluid is halfway up the dipstick tube when the engine is off.

[KR Convertible]

I have not had trouble with C4 pan leaks. Often the O - ring on the dipstick tube leaks, resulting in the appearance of a pan leak. Make sure that is not your problem. Fluid is halfway up the dipstick tube when the engine is off.

+1  Make sure the dipstick tube isn't bent a little.  The mounting tab should line up without having to put much pressure on it.  You may need to bend the tube so it lines up nicely.  If you have to force the mounting tab, you are distorting the O-ring.  Ask me how I know.   

[Greg]

I have had the same problem and I finally found it, at the shifter shaft.  Change the seal and don't drive it all the way in, just flush with the case and put some sealer around it.

[rhjanes]

I'd suspect the shifter shaft also.  Then the dipstick tube.
On my 1969 C4, the shifter shaft leaked but only after it sat for a few days.  For the fluid to leak down from the torque converter and other places.  That went on for.....years.  Until I decided since it was the last piece never rebuilt, to have it done.  It hasn't leaked a drop since (about 5 years or more now). 

[GT350AUS]

Dip stick O ring may be the culprit as the leak ran like a tap once i had filled 4 quarts down the dip stick shaft.

Selector shaft is dry as a bone.

I'll get back with my findings once i get back on to it,

[Royce Peterson]

I had one C4 dipstick tube that was cracked in the O-ring groove. Kept replacing the O ring and it kept leaking till I finally realized it had a hidden crack.

Dip stick O ring may be the culprit as the leak ran like a tap once i had filled 4 quarts down the dip stick shaft.

Selector shaft is dry as a bone.

I'll get back with my findings once i get back on to it,

[pmustang]

I feel your pain, I have 20 or so in the shop.....exxon Valdez comes to mind. As mentioned dipstick tube seal. But other times you can't get the pan to seal so we chuck on a new one. Good luck. Peter

[GT350AUS]

I put more fluid in while on the hoist and found the O ring at the tube is fine but it ran like a tap from the shifter shaft.

So shifter shaft seal it is.

[rhjanes]

I put more fluid in while on the hoist and found the O ring at the tube is fine but it ran like a tap from the shifter shaft.

So shifter shaft seal it is.

Thanks for the update!  Like I posted, mine had to sit a few days to leak out.  When I daily drove it, it never did it (much).  I'd keep the fluid just at the "Full when Hot" line, then it would sit for about 3 days and start dripping.  It would also drip out a set quantity and stop (guess it got down to the bottom of the seal). 

Since mine had never been rebuilt, I just pulled it and had it rebuilt. 

[GT350AUS]

Yep rhjanes, sounds the same as mine.

I'd like to give it a go myself and hav found a YouTube video that shows how to replace it after removing the the pan and valve body to get to the nut from the inside and remove the shaft to replace 2 seals.

Is there anything to watch out for on reassembling the valve body and torque settings. I don't have a manual to refer to.

[GT350AUS]

Also one of the videos online shows a spring with plunger between the filter tang and the valve body.
I've had my filter off and no sign of a spring with plunger. Is this normal for the C4 on my Hertz?

Was this a mod done Shelby or am I missing something here??

[OldGuy]

Also one of the videos online shows a spring with plunger between the filter tang and the valve body.
I've had my filter off and no sign of a spring with plunger. Is this normal for the C4 on my Hertz?

Was this a mod done Shelby or am I missing something here??

The spring and plunger you are referring to are for a later model C4 ('70 and later).

Frank

[rhjanes]

Yep rhjanes, sounds the same as mine.

I'd like to give it a go myself and hav found a YouTube video that shows how to replace it after removing the the pan and valve body to get to the nut from the inside and remove the shaft to replace 2 seals.

Is there anything to watch out for on reassembling the valve body and torque settings. I don't have a manual to refer to.

I only removed my C4 and took it to a rebuild shop.  So I'm not sure what all tricks there are or torque settings for the C4.  Sorry. 
Others will chime in.