Shifter problems in the cold
 

So the cold weather is here. In the mornings it is very hard to get the shifter in gear. However, when I go through the gears a few times and start driving it, the shifter progressively gets better.

I'm thinking I need new transmission fluid, but I want to make sure that's actually the problem before spending the money to replace it. It's only going to get colder in the mornings so I would like to get this done soon. Any ideas?

The Mustang is a Mach 1, has 102K miles, a Steeda Tri-ax shifter and I recently got an Exedy Mach 400 clutch along with a Steeda clutch cable and quadrant.

Thanks for any help!

That's what I would do just make sure u get the right weight of gear oil