I have a 97' F150 Supercab 4x4 Long bed (8') 4.6L 3.55 gears
with 77000miles. A short while ago my truck was starting to howel at speeds of 50mph and higher. now its gradgualy showing at all speeds. the noise seems to be under the supercab below the seat it dose not sound any difrent in4x4 I change my fluids very regulary and have seen no abnormal problems I recently changed my u-joints for a "erclunking"sound last week and that did not solve the problem for that thinking its in the howling problem. some think its in the trans yoke housing? Is this true? If you have any insite Thanks, I cant even stand to drive more than 20miles before it gives me a headake!

 

I would say something isn't lining up right in the tranny, i couldn't tell you the exact problem though. Sounds expensive

-Jon

 

Is the noise more noticable when O/D is on or off? Is noise more noticable when accelerating or coasting? Doe's noise make any audible difference when changing lanes or turning corners? Or, is noise there regardless of whatever you do?

Is differential pinion yoke loose, or does it have any up & down play when you lay under vehicle and push & pull (vertically) on the pinion yoke at the differential? Is there any noticable leaks @ trans., diff. or other driveline areas (such as transfer case)??

 

None to all of the above, accept for it is there regardless of whatever I do. Ive checked the pinion to be loose found nothing, I ve pushed and pulled nothing, and no leaks. Its a solid noise in 4x4 O/D on or off. just gets louder with speed it starts around 10 mph and gets louder. it used to start at 55 mph. it sounds like raw gears or bearings. When I put it up on jacks it sounds like it is comming from the yoke housing. I just wanted to be sure before I start putting money into it. If it is that how hard is it to repace? and how mouch do they run?

 

Doe's vehicle make the noise in 2wd high? Have you changed lube in transfer case or sampled derbis on magnetic drain plug? If so, is the lube in transfer case metallic looking? To your knowledge, has the transfer case been ran low on lube or ran with no lube in it?

 

Smark,

I have a '97 F150 4x2. I'm having the same problem with a howling noise at all speeds. Did you ever find out the cause of the howling noise?

Par66

 

In my '95 F150 4x4, I started to hear a howling sound from underneath. It sounded alot like having really aggressive mud tires on when you drive down the road. I thought it was my tires acting up. Ford found the rearend had to be completely rebuilt. Fortunately, it was at 25000mi and was under warranty. The mechanic said there was something RADICALLY wrong. He said when he took the differential cover off, chunks of metal came out with the fluid. Here's what he did to find it. He put the rearend up on jacks like you did and let the truck run to pinpoint the howl.

My best guess is that your gears in the rearend are going kaputt. Please have a mechanic check this out ASAP as it could be a hazard in the near future.

To replace the gears, the axle shafts have to be pulled out. It's not an easy task from what I understand. So you can probably expect the cost to be on the high side. But, it's better than being stranded somewhere because the rearend just gaveway.

 

I've traced the same problem to a insufficent preload on the carrier bearing in the rear end .Figured that out after a so called expert changed my gears from 3:08's to 3:73's and said that the factory had put way to much preload on them ,but then the howling started so guess what/ put extra shims back in and it is now quiet. I heard rumors of incorrectly machined rear end housings needing extra preload to quiet them in the same manner,has anybody else seen or heard the same

 

I have a '98 4x4 4.6 with the 3.55 l/s rear end. I had a howling noise coming from th rear. I took in to have it checked out and, as we speak, it is having the rear end rebuilt.

 

Mine has a similar noise to it except my tranny doesn't always seem to shift right either. Hope it's not the rear end howling going out or the tranny or even worse both! Replacing gear oil tomorrow with Amsoil. If I find chunks in my rear diff I may just cry and then push the truck over a hill. JK, LOL I owe to much to do that.