About a month ago I bought a 2005 Lariat 4x4 Supercrew with about 29k miles on it. This past week I have noticed an occasional 'hard shift' from 2nd to 3rd. Also, at times it seems to over-rev slightly at slow speeds before it will shift. Is there a known defect or problem with this transmission? I have towed my boat a few times (approx 3900 lbs), but otherwise I baby it. Any information would be appreciated, I'd like to get this solved before the original warranty expires in 6,000 miles.

 

In the 04+ forums, this is known as the "clunk". Quite a few have experienced it and there is a TSB out for driveshaft. Most dealers lube the slip yoke. Members have had this done 2x or 3x before dealers will consider replacing the driveshaft.