Leaking E40D
 

Thanks in advance for helping me. I just purchased a RV and did notice the transmission was leaking around the CORK gasket at the trans pan before I drove it home. The RV seemed to drive ok during a test drive and while I drove it home about 75 miles. I wouldn’t be surprised if the trans was low on fluid when I drove it. When I arrived home trans fluid leaked all over my driveway while I was moving the RV into a tight parking spot. I am not sure if it was leaking around the trans pan gasket or somewhere else. I did replace the gasket and filter and replaced the fluid (3 gallons). The new gasket was a RUBBER gasket and I used a small packet of gray RTV. I drove the RV about 40 miles and did not notice any leaks and the transmission again seemed to shift smoothly. After the RV sat in the driveway for about 1 day I now notice a wet spot under the RV that is trans fluid and below the pan. Again the new rubber gasket is wet. It is leaking almost around the whole gasket, not just one corner, spot etc. My question is should I use the rubber gasket or should it be cork? I might have tightened the screws too much I am thinking. The trans is a E40D Ford and the RV is a 1997. Do you think the trans needs a rebuild? What are the symptoms of a trans that will need a rebuild? Is there a way to test the transmission to see if it is ok? I don’t want to take it somewhere to fix the leak only for them to tell me that I need a rebuild when the trans seems to shift and operate normally. I hope you understand my concerns. Yes I do want to fix the problem and will pay to have it fixed but I don’t want to be overcharged or charged for something that I don’t need.
Thanks,
Phil

The Ford original gasket is rubber and FAR superior to the cork gasket. The rubber gasket is also reusable.