Hard shifting transmission
I have a 1997 Avenger ES that I am about to do some maintenance to. The car has around 150,000 easy miles on it and is running fine except for a couple of things. First off it will stall a bit at low speeds or at an idle which I suspect might be from a dirty fuel filter, which I am about to change this weekend. Also, the transmission seems to be slipping a bit and shifting hard so I will change the fluid this weekend as well to see if that helps. I would like to know if I need to put sealant on the transmission gasket? In the past I was told you need yellow silicone on the gasket but now I see that no sealant is needed on the gasket. I did notice that there is some fluid leaking under the car around the transmission pan and oil pan but that may just be blowing off the transmission pan. I have not really investigated that yet.
Anyhow, what else might be causing the stalling and hard transmission shifting?