Hi All,

It has been a while since I have posted. Was going to take her out for the first 2025 warm up cruise of the year.  Noticed a large amount of tranny fluid on the floor. She has been sitting since November 2024. Anyone ever hear of the torque converter draining and causing this fluid loss? If so, what could be the issue and how will I know if the converter has enough fluid in it before I take her out for a ride. Any assistance would be much appreciated.

Thanks,

 Kenny78

Can you see where the fluid is leaking from (overflow from the dipstick, bad gasket, etc.)?

When the engine is run, the trans pump should fill the converter, then you can check the fluid-level with the dipstick.

The torque converter itself will not leak like that. If it has developed a leak while sitting, converter drainback can cause the fluid level in the pan to rise, and will sometimes find weird places to escape. Most likely suspect is a pan gasket. The older cars with the 400 trans would also sometimes leak around the pump o-ring after sitting idle for a while, but your '78 should have a 350 trans. I would first suspect the pan gasket, but other leak points will be: shift shaft seal(where the shift cable linkage attaches), speedo bullet/cable, dipstick tube, kickdown cable, and the 2-3 accumulator cover on the passenger side. If the fluid level gets really high, it could also find it's way out the rear seal. 

I would suggest filling the trans with the proper amount of fluid before driving it. Unless the fluid is just pouring out with it running, you should be good to go for a drive once the proper fluid level is attained. Use a quality brand Dextron III fluid. 

Our '78 has a really annoying and persistent leak from the speedo drive. 😡  I have replaced the whole unit,(drive gear and the "bushing" it runs in) but if the car stands for a couple of weeks it still leaks.  But if I use the car regularly, say every week, it stays dry.  I have cleaned the whole trans, so it is easy to see exactly where the leak is.   I'd have another go at sealing it, but due in part to the custom exhaust on our car, it's a real pain!   So I just make sure I have a little "drip tray" positioned under the speedo drive housing, and that way I can monitor the fluid loss.   In reality, it's not much more than half a pint a year!

Many years ago the pan gasket was leaking, but I replaced it with a GM cork item, and was careful to follow the tightening sequence outlined in the manual.  That cured that issue.  I gather that the dipstick tube can also leak, but that has not been the case with mine. 

I suggest cleaning everything down underneath, getting the car warm and checking the fluid as per the manual.   Re-fill as necessary (it doesn't take much from "Add" to "Full") then monitor where the fluid is coming from and how much.   Trans fluid is ghastly stuff and a tiny amount on the floor looks like a gallon!😄