My 2007 jeep commander randomly won't start, why?

What is your question?

Started 2 years ago, randomly won't start. Is now at dealership, been towed 4 times, everytime it rolls off tow truck it starts. For the 1st time dealer actually have got it to duplicate the problem but no codes come up so they can't find the problem!! It did have transmission over temp, but they did do work on rear differicial and that light went out, but then wouldn't start after I test drove it and so they now have it still and have had it several times trying to figure the issue. Do they not look at blogs to find out that others that own the same commander have the exact same issue ??

What makes this problem better or worse?

Don't seem to matter the weather or tapping on starter

How long has your 2006 Jeep Commander had this problem?

Over 2 years