I have a 2003 limited with 120k on her. Recently the gear selector got a loose sloppy feel to it and will not stay in 4th gear, slides over to D. Will stay in other gears just fine, but now I have to drive in 3 or D. Toyota wants $1,000 to fix and put a new unit in my vehicle. Has anyone tackle this repair as a DIY? Seems like it is just the box bolted down and a wiring harness plug in to it. Toyota wants $650 for part alone, but I found a Dealer than sells online and wants $450 plus $50 shipping. Thanks