Hi...... 2002, 5.4 crewcab, 88K miles. Did: pull on truck that was trying to pull a bigger truck out. I was on pavement. I gave steady gas, but not enough to spin tires. Does: On the way home 1 1/2 hrs. later, after driving the same as it always has (great), it starts to make a higher pitch noise w/a up/down pitch change. Most of that went away and slight clunking, mostly a rattling noise started/persisted, (a bit intermitent) the last 15 minutes of the drive. One big clunk on a slow down. Otherwise, it felt pretty much as smooth as always, during this. Took off cover to rear differential today. All looks fine from what I can see. Backed up (a little clunking), drove up and down the road a couple times now..... nothing. Seems fine. Do: Think I might button back up and test drive for a while. I live in town and it'd just be short drives. BUT, I have a long drive coming up (same drive when the troubles began and will be towing a boat) and I'd prefer not to break down. Appears heat build up from a longer drive may affect this problem. I'd appreciate any and all ideas anyone might have to share. Thanks!!

 

Nevermind...... been thinking about it this morning. Odds are heavy that the input pinion shaft is the most likely item to bend. Ever so slightly, that it doesn't cause problems til a long drive and the heat eventually affects the tolerences. Something could have slid, but I doubt it. Sure don't see it.

 

were you in 4wd while pulling and on pavement? guessing the noise sounds like it's coming from the rear.

the clunking almost sounds like u-joints.

 

I'm old enough that I was around before front wheel drive. I remember the clunks from driveshaft u-joints when put in gear and letting up/stepping on gas while driving, when they were going bad. I was on pavement, not in 4WD. I've made this drive many times and had never had a prblem w/the truck til right after doing this. Looking at the diagram of rear differential, looks like the input pinion shaft would be the most likely spot to bend being it exerts outward force. I didn't think I was putting too much pressure on it though. ***** truck, I guess.