I've been noticing my 2008 Edge SE AWD shifting hard lately. It originally was very intermittant, now it more frequent. One thing I have noticed with the hard shifting issue is, it seems to have started when my tires started to wear rapidly, especially the front tires. The front tires are in worse shape then the rears. I'm not sure how this happened as I have rotated regularly. When I asked the tire shop to rotated them the said it was best to keep the better tires on the rear, so they didn't rotate. Now that the front tires are worn more this hard shifting issue has become more frequent. Now the tires aren't that great of a tire, my mistake. I'm thinking the tires wore so quickly do to the cheap quality, or alignment needs checked. So what leads me to think it may have something to do with tire wear is that AWD vehicles are very touchy when the tires are not at or close to the same tread depth. As well all 4 tires must be the same tire, same brand and same tread pattern or you will have major drivetrain issue.
I'm not saying this is what is cause this issue to occur, but could be affecting the drivetrain in some way. So, everyone check your tread depths on all 4's. I'm not 100% certain but I remember the tire shop said that if there is a 2/32 or 3/32 difference between the front and rear tires that it may cause tranny issues on AWD.
