What did I do? 2001 grand Cherokee 4.7

Saturday I was on the expressway noticed I was going 75 in second gear probably for 5 or 6 miles. Put it back in drive, that's when things began to go bad. The tach started bouncing around an the engine shut off, temp was all the way to hot. Would turn over but not start. Finally got it to start when the temp came down. It ran really rough, made it far enough to get me to the next exit. Started to make some noise kind of a rattle quit and would not start again. Where should I start, how do I check what I need to check? Timing, spark, fuel? If this was a pre 80's push rod engine I would have no problem.

 

Scan for any codes and post them. Can't imagine 75mph in 2nd gear was good for the Jeep

 

P0601 is only code showing, but have had that one for along time.

 

I did get it to start for a moment, had to crank for more than 30 seconds, no tach signal while cranking it bounced a bit than started. Has a rattle on right side of engine. Will not idle.