I have a 2004 Lincoln LS V6 with automatic transmission ~170k miles on it right now. Recently my automatic transmission started making a very strong kick or jolt as it shifts gears. Once the car is in gear, is drives nice and smooth, but I literally have to brace myself for every gear shift. Happens both when upshifting and downshifting. The kicking/jolting is actually so strong, that at one point my drive shaft snapped. (drive shaft is fixed now).
What the hell could this be? Transmission fluid was changed twice in last year along with filter. Valve body looks fine. No check engine codes.
If the ATF level is fine, nothing else you can do yourself. It could be so many things, Have a pro check the transmission.
Make sure when you check the fluid that the car is hot and running and by hot I mean normal operating temperture.