2002 SLT, 4WD, 5.9L, AT.

Started hearing a noise that seemed to be coming from the left front wheel the other day. Best way I can describe it is a humming or whirring. Wasn't very loud and I was thinking wheel bearing. Had an appointment to get it checked on Thursday.

Fast-forward to today and the noise changed to some clanking and grinding. Turned around to go home. Didn't quite make it when something went clunk really loudly. The clanking got much louder. Put it into park and it started rolling downhill. Moving it to R or D resulted in lots of noise and no movement. Had to use the emergency brake to keep it from rolling down the hill.

Called for a ride home and tow-truck. Ride shows up and says to try switching from AWD to 4-HI. Did that and everything seemed to be fine. Cancelled the tow-truck and drove it home with no noise at all.

Obviously it still needs checking out, but I'm wondering if anyone has an idea before I haul it in.

Thanks!

 

sounds like your front diff or a front cv joint went bad. In awd there isn't any limited slip between the front and rear axles so all the power was just going to whatever is busted in the front end. The reason it worked in 4hi is most likely because the rear and front axles are locked together in 4hi and the rear was able to drive instead of all of the power being wasted at the busted component at the front. This is also why park wasn't working. Whatever is broken was spinning (in the opposite direction) that the truck wanted to roll allowing the truck to roll in park. I'm guessing park worked fine in 4hi?

 

Thanks, that guy.

Park did indeed work fine in 4HI. In fact, everything seemed to work fine once I switched.

 

It sounds like your transmission and transfer case are fine then. The problem is probably a cv joint (could've been the noise you heard) or the front diff.

 

Dropped it off at a shop this morning. Should hear back from them this afternoon. Thanks again for the help. I really like having an idea of what's wrong before I take it in.

 

yeah, a lot of mechanics will really rake people if they don't know what they are talking about. Hope everything gets taken care of.

 

Turned out to be the front drive shaft. They had to order the part and it should be ready later today (and I'll be $500 poorer ).

 

At least you'll have it working again

 

A lot cheaper than a diff or being a mechanic and trying to make everything perfect on your D. We notice every little problem with our rides...
My last bill was $2100ish...