Hello everyone! I am new to this forum. I have an 05 coupe with the 4.0 and auto trans. I am having a problem when coming out of park into reverse. Sometimes the transmission hesitates to lock into gear and then when it does, it slams hard. It does not do this all of the time and I have no other problems. It shifts fine from 1st to 2nd and so on. The car has 78,000 on it. I had the tranny fluid changed at 60,000. My wife took the car to a garage and the mech told her that the tranny is bad without so much as opening the tranny up. He did service the fluid level and charged us 30 bucks. Has anyone out there had this problem or heard of someone having this problem? Thank you for any help you can give me.

 

In my time here I haven't heard of any other high mileage Mustangs having this problem, V6 or GT (GT auto is the same as the V6). I'm at 60k myself, just got the fluid changed. Hopefully I don't encounter any issues. But I'd say take it to someone else and get it checked.

 

Yikes! I'd personally suspect the service. Might not be enough fluid in the tranny, or some poor quality fluid or the wrong type of fluid may have been put in.
Luckily so far your forward-shifting is still ok.

 

I have a 05 with 55k miles and its an automatic.. I have had it have a slight delay going into reverse when it is cold but I live in MN where it is -30 right now. If I let it warm up before I drive or its warm out being close to spring I have had a few 40+ degree days and it works fine no delay at all but it never slams into reverse so you might have a problem

 

Your pump is wearing out and the operating pressures are decreasing.
Or your filter is beyond clogged.