Thanks for the welcome.
I have been leaking transmission fluid ever since I bought my 68 Cutlass "S". When I first went under there (1997) the pan seam and speedometer cable housing was caked with gasket sealant, so I proceeded to remove it and bam, transmission fluid drips everywhere. I have replaced the gasket about a dozen times without success. Should I buy a new pan, or is this something that is common with this vehicle / transmission. I am not sure what type of transmission is in there, but I think it is a 2 speed automatic hydroglide or powerglide, just not sure... I am not sure what to do with the speedometer cable at all. The speedometer gauge on the dash clicks and bounces.
JC

 

I had a similar problem w/our/ '68 Flat Top Wagon w/the 2 speed 300 (NOT POWERGLIDE). Think Oldsmobile called it Jetaway. Anyway, as I recall, our technician replaced an O-ring at the speedometer cable inlet on the side of the T/M, and it cured the leak. As I didn't do the actual repair, cannot be more specific. Would certainly consider taking it to a bona-fide, GOOD, T/M repair shop. Hope this helps, and Good Luck.

 

JC, you might check the speedo cable or dipstick tube like Aron mentioned. It could be leaking someplace else besides the pan. Clean the underside of the car really good with engine degreaser or oven cleaner and a power washer and then drive the car around town so it gets hot (not too fast). Then get under the car and check for the leak.

BTW, you shouldn't use RTV or gasket sealing compound on an automatic transmission pan. It could ooze out on the inside of the pan and seperate and get lodged in the valve body.

 

Correct, the Super Turbine 300 (ST300) was called the Jetaway by Olds and was offered from 1964 to 1969. It has the same gear ratios as a Powerglide, but no parts interchange. As for the speedo driven gear housing, there are actually two o-rings to change, one on the outside of the housing that seals to the case and one on the inside of the housing that seals to the speedo driven gear. The problem is usually the inner seal, but change them both while you are there.

 

I will get the O-rings for the speedometer housing, thanks.
For sure the gasket seal is leaking. Unfortunately I did use the sealant on the gasket, but only after 2 attempts with gaskets that did not require it failed. I torqued the bolts to the correct specs. (I would have to look them up again) I know I should go to a shop and have it done but it is not in the budget if you know what I mean.
Thanks for the info on the type of T/M.
JC

 

Check the pan flange for flatness. It is common for the flange to have been distorted by overtorquing the pan bolts, especially if a thick cork gasket is used. You can flatten it back out with a hammer and dolly.