I have a 4l80e in a P30 chassis. (Motorhome) I have changed the rear seal, dropped the pan and put in a new filter and oil. I went on a trip with my car trailer attached. Everything worked fine,(overdrive, cruise shift points). After parking it for a few days , on level ground the trans has a slow leak at the rear. This unit also has a drum brake on it for parking. The inside of the brake is dry except for a small amount of oil at the bottom. I'm stumped. Any suggestions. Thank you.
ok, I am hearing about what you did but I don't have any idea about why you did it. Did you have a leak before? is that why you changed those parts?
If you notice a small leak after it has been sitting for a while, where does it look like it is coming from? You may have to clean everything underneath and let it sit and see where the leak originates from. When you did the rear seal, how did the surface of the metal yoke look and feel? Did it have a worn area where the old seal rubbed on it? You may need to replace the yoke on the drive shaft or put a speedi-sleeve over the worn area to give it a smooth contact area.