I have an 05 F150XL 4X4 with the small 8 and about 2K mi. I just towed a car on a trailer today, and when I got to about 50mph a really loud howling noise came up through the bottom of the cab. It seems to happen when it's under load but moving along. If I let off the gas a bit, it goes away. You can actually feel a vibration through the floor. This is with the OD locked out. I noticed a little bit before just crusing on the highway if you come to a hill or go to pass. But today it was REAL loud! This can't be good! Transmission? Engine? Any Ideas???

 

The only thing I've read up till now about a noise like that is the rear end. I'd have to start with that, particularly with the vehicle under load with a trailer. I thought you were supposed to limit towing for a few thousand miles until everything was broken in, but maybe it was just the first 1K.

 

veja i noticed you said that the od was locked out, and that you noticed it before on the highway was that with the od off also? why ask is because with od off the rpm's are higher and at highway speeds it seems like you need another gear and there is some roar, now i dont decribe it as you do. but coming from below you i'd say tranny.

 

I agree with exiled here. Bout the only time you would want to turn OD off in My opinion is when you are traversing alot of hills and such or some city driving conditions which might be causing your truck to continuosly shift in and out of OD. But traveling at Hwy speeds...I can't really see any other reason then the aformentioned to turn it off.

 

Good point guys, but do you think the tranny would be that loud? than again, it's hard to decide just how loud something is by explanation alone. What's loud and abnormal sounding to one person may be consideredusual by someone else. I've driven in OD lockout around the city, but never encountered it on the highway. Maybe I'll do an experiment this week and see if i get anything like that.

 

I have also previously noticed the noise IN OVERDRIVE, when the engine loads (but not towing anything), ie going up a hill or passing @ 50+ but only once in a while and not that loud. This time towing though it was very loud howling, you would have to raise your voice if you were talking to someone. But, just let off the gas a little and it would go away, step on it, it would come back. It's not coming from the rear of the truck like rear end gears, but it did cause vibrations through the floor. It will be tough to replicate to the dealer since it's not all the time.

 

veja i would think its the tranny but not the od like i was thinking. i understand that its only sometimes but does shift at normal rpms or is it just noise? i did note that you have vibrations. with you saying that when you let off the gas it goes away that kinda alimanates the wheels as that they still be turning the same rpms for awhile after letting off the gas. that leaves the motor and tranny. if you hard accularate is it loud like that thru all the gears or just high speeds?

 

I heard something like this a few weeks ago on my '04 Supercrew. It last about 1.5 minutes. I was accelrating from a stop light and all of a sudden the truck strated to shake and vibrate BAD!!! As abrupt as it started it stopped. I thought it might be related to an accident I was involve in in June. (BTW My old truck has spent a total of 12 weeks in the shop. 9 weeks the 1st time, then 1 week an now 2 weeks because of water leaking. I told the body shop and the insurance claims guy to total the truck this last Friday. They said they couldn't so I went in to the dealer and even though it is in a million pieces I their shop I traded it in, got $18k, and bought an '06 Supercrew).

Anyway I talked to some people in the know about cars and 1 guy said it could the the torgue convertor and another guy said it was stuck trying to shift into 3rd gear.

Good luck

Rich Dunklee
NR2D

 

Might be the engine Fan My old powerstroke would make that noise under a big load