Trans cap stuck

[Jack Urban]

Hi Guys,
 I’m working on a 42 Cadillac that had been sitting for a while. I drained the trans fluid and replaced the gasket. I used the high temp silicone gasket in a can because the company I bought my gasket from said he did not have a 42 Trans pan gasket. So I thought I would try the liquid gasket stuff. To add the Trans fluid I have to enter it under the floor carpet (m what idiot thought of this) my problem is I can not get the Trans fluid cap off. I got the floor pan cap off but I can not get the transmission cap off. It will spin and seams loose but it will not come up. Before I damage it, am I missing something? My other question is, is the dipstick that close to the pan where some of the gasket material stuck onto the dipstick?

Thanks
Jack

[Doug Houston]

This one is a bit unusual. Obviously, the transmission is a Hydra-Matic. O.K., the dipstick might have been someplace else, and was later, but its better than the days when they had the battery under the front seat!  I figure that since the transmission was the work of a lot of mighty good engineers, they had a right to do some thing that might rankle somebody, some time.

Ive never had one stuck like that, but I wonder if it could be carefully pried up and off. There is almostt no possibility of your sealer getting it stuck, so there is probably some corrosion holding it. The dipstick cap is also a vent, which is necessary . The transmission gets pretty warm  (alright, hot) in operation, so air has to be vented.

[Jack]

Thanks Doug
So far Ive tried pulling it up from the top and pushing it up from underneath. Most likely Im going to have to pry it off and destroy it, unless it finally gives way. Is this one of those parts Ill never find again?

[Doug Houston]

Just checked. The dipstick for the 42 trqnsmissions is for 1941 and 1942. There should be someone who  has junked a 41 or 42 transmission, and who has the dipstick. The dipsticks for 1946 through the last year before the dipstick under the hood (dont have it here, but 1953?) are all the same.

Now, heres a question: could your transmission have been replaced at one time with a postwar unit? The quickest way to spot this is if there is a large hex plug in the top driver side of the transmission in the front of it. if so, its a postwar trans. Its the pressure regulator valve, and not there on prewar transmissions. The probability of getting a dipstick for the 46 and leter transmissions would be stronger. I suspect that the only difference between the prewar and postwar dipsticks is the length of the rod.

Ive never had this problem, so its a bit mysterious to me how you might get the dipstick out. If the space beneath it is clear, could you get a piece of pipe, about 1/2 inch, and drive it upward from below? Or is that what youve already been doing? Sounds like it must have rusted in place.

[Fred Garfield]

I must be misunderstanding something, Doug. Jack said it spins and seems loose but wont come up. If the problem were rust, wouldnt it bind rather than spin freely?

[Doug Houston]

Yes, the cap on the dipstick spins freely, but iss still stuck. On the surface, it sounds illogical, but the dipstick plug is also a vent for the transmission, so the hat on the dipstick plug is loose, as a vent cover should be. But in this case, the part of the plug that fits into the filler mouth appears to have been stuck with possibly a little collar of rust.

[Fred Garfield 22310]

This is an interesting problem. I have no idea how this part is assembled, but Ill be following the thread to see how it gets resolved.