LanceK

I did my first long distance tow a couple weeks ago. I was towing an enclosed trailer weighing approx. 4,000 lbs.

While going up some decent hills in Pennsylvania, the truck would have a noticable "drone". I think the RPM's were holding steady about 2000 and the speed was between 65-70 mph.

It didn't sound like anything was broken or was about to break, but it was noticable enough and could have been a little smoother.

Thoughts?

CUM4X4MINS

Sorry man I don't know much about noises on STOCK trucks cause mine wasn't stock for very long after I got it, a couple days maybe.

But is it a bad drone your hearing or is it just the truck is still trying to pull the load up will is still in O-drive causeing a deeper drone from the exaust, insted of down shifting a gear?

Betsy II

It might be the clutch locking up on the cooling fan. The first time this happened to me was towing up the Coguihalla in southern BC. It's quite a climb. I had never heard the noise before. The service manager at my local dealer had no ideas. I think if you do a search on this you will find more info.

I have the 48RE and I suspect it was getting warm so the clutch locked up on the fan to provide max cooling for the tranny fluid.

Good luck,
Roy

Ramcam

I have this same problem with mine.I took it to the dealer last week and they put in a complete driveshaft assembly.Took it out and it still drones between 90 and 100 k.Mine seems to drone when it hits lockup and it is annoying when going up long grades under load.
I'm going to go back and get them to disconnect the front driveshaft see if that makes a differance.I am not happy about the drone i can live with the noisier diesel but the drone has to go.Didn't pay over 50 grand for that.

LanceK

I'm not sure about the tow/haul or overdrive mode.

I'm still a little uncertain on when to use either one.

Since I was only towing 4K and it was my first long tow, I wanted to see how the truck reacted on its own.

Only once did it start searching for gears and then I put it in tow/haul. I tried putting it in tow/haul a different time when it wasn't searching and the RPM's went through the roof so I put it back into overdrive and left it alone.

Ramcam

Mine does it whether in tow haul or not.When it drones i can feel it through the steering wheel slightly as well.I have two friends with the same truck i asked one whether his droned or not he says not,so i'm gonna go out when hes towing and see for myself.Sometimes i think most people think this sound is normal while towing and ignore it.My dealer also said that it may be an exhaust noise so i will keep working at it hopefully get rid of it.Diesels have alot more vibration funny it becomes a droneing sound.Keep posting on what you find out..... Cheers

stock03

Isn't that known as the "Cummins drone"? Mine does that too at about 2k rpm when under load. I think that is pretty much normal. If mine is at 2500 rpm, it's quiet and smooth as a gas motor, even under load.

Lrdchaos

When I had the stock exhaust on my truck 2k rpm there was a drone, when I installed my cat back exhaust, it eliminated the drone. I believe some of what you are hearing is the normal sounds comming from the engine\exhaust.

XLR8R

LanceK - what year is your truck?