Seems on some mornings, say in the first 3-4 miles.. I have to mash the clutch all the way in before shifting to 5th or 6th.. or it will grind the gears as it goes into gear.

Sigh. Reasons for this? cluthc going out on me? Works fine after it warms up and works fine in 1-4th

 

The over drive gears are clearly not performance gears . The best performance of the car in general and certainly the trans is not going to be when it is not up to temperature. You already know it clears up when the car is warmed up( 3-4 miles) . Having to mash the clutch sounds like you usually don't fully dis-engage the clutch? Or perhaps your release system also is not cold-blooded. I would check the hyd. fluid/ system health and accept that the car requires coddeling in the morning..

 

I find alot of cars that the pedal is not up to snuff cold. Once the fluid heats up & expands a little it improves.