I tried this in the Excursion forum and I figured I try here as well...

Over the weekend I had the utility trailer hooked up and was on an uneven dirt lot. I was backing up a hill and as it got a little steeper there was a loud grinding that sounded like it came from the area under my feet…almost like the motor separating from the tranny. Pulled forward and onto level ground and no grinding sound, started backing up the uneven hill again and the bad grinding sound happened again. Ditched the trailer and pulled into the driveway. Got under it and pushed and pulled on everything around and nothing seemed loose, no fluids leaking and nothing abnormal.

Any ideas or other things I should look for?

 

when backing up, were u in 4wd? also, please list symptoms like, e.g. were u on 4wd lo or high? how much weight u carrying? wat did the incline look like?

off-hand, sounds like ur front transfer case or somewhere in ur front wheel assembly tats slipping. losing traction.

if loud grinding noise and sounds like gears, then it may be the transfer case. possible slip on the gears. i dunno. i could be wrong.

jus a guess. i'll try to chime back wif more info. back to work now. urgh!

 

Thank you for your reply. I was in two wheel drive, towing less than 3,000 lbs, dirt incline was pretty decent and uneven.

 

I am very interested in seeing the responses to this as well. My 04 F350 made similar noises while towing an 18 ft camper trailer up some steep rocky grade in the mountains of Colorado. It was maybe 45 minutes of 4 low uphill and into a campsite. Then I needed to back it up some and heard a grinding that increased parallel with the engine RPM's as I pressed the accelerator. (I figured the tranny was slipping ....torque converter not locking up??) I had shifted out of 4 low into 4 high when this happened. Shifting back into 4 low enabled me to reverse. I occasionally get the same noise when lifting off the accelerator after a hard acceleration.

 

@ howard1, nah i dun tink its the tranny, or u'll hear it all the time when in 2wd mode driving on the way to church or to the donut shop.

it happens when ur in 4wd mode? then its something to do wif ur gears in the transfer case. when shifting into 4wd or from low to high, did u stop and set to neutral, before selecting 4wd low? you have to do it like that to allow the low gear to engage.

since its not the regular tranny, then it cant be the torque converter.

@ scottf4444, ur welcome. hmmm......sounds strange. does tis happen when ur backing up on a gentle incline or was tat jus a random situation?

it may be a bad front axle and hub. it could be ur wheel bearings which need replacement.

i'd try jacking up ur front end and start moving ur wheels like i'm turning them if there is too much freeplay. i'd check ur ball joints. check for anything loose.

i'd also check the power steering fluid. maybe it's time to flush the power steering fluid.

hope it gets u started in the right direction.

 

Does you're truck have a AM exhaust?

 

Yes, RBP turbo back.

 

Jacked it up yesterday and the hubs are good. Ball joints were replaced 10k ago. I can't get it to make the noise except when reversing up and incline.

 

hows ur sway bar looking? wat about wheel bearings? did u try to move ur wheel left and right? if there's too much free play, then ur idler arm and pitman arm are worn out.

the grinding noise is not from the engine.

 

I think I know where unreal04 is going. May sound silly, but check your exhaust clearance. Especially where it makes the first bend to run parallel to your frame rail. Mine was in close proximity to the shock mount bolt and although the pipe was dimpled to provide clearance for the bolt, on tight turns or frame stress situations contact was being made. The noise/vibration felt just like a wheel bearing or ball joint going bad.

 

hmmm.......sounds like u make sense , w1!dbill. tat is possible as well.

 

Thanks guys! I will check all of this out.

 

Snuggyworm,...Thankyou for the intput. To clarify, I do hear it in two wheel drive when I let off the accellerator suddenly after vigorous accelleration. Not to high jack the thread, but it sounds exactly like what Scottf4444 is describing.

 

Yeah I forgot about this thread. I've noticed that my 4" turbo back can rub the fire wall in reverse or when my frame stretchs. It feels and sounds like grinding near your feet.

 

I had a similar noise. It was the down pipe rubbing on the firewall (sounded like the transmission). Check your down pipe clearance at the firewall. Climb under the rig, and with someone you trust behind the wheel have them put the truck in gear (forward and reverse) with their foot on the brake and throttle up to see if the motor torque is forcing the down pipe against the firewall.