Request help in ID'ing Front End Howl

[slepe67]

'95 F250, 4x4, auto. Everything is bone stock.

About 5,000 miles ago I changed out ALL fluids, u-joints, carrier bearing, shocks, tires, (brakes are good). My TTB D50 is junk. I need to replace it BAD. Until then, I have to keep it on the road.

Today, my daily driver suddenly developed a front-area howl when driving. Louder the faster you go, quieter when you slow down. I inspected the wheel bearings & brakes Friday when I had it up on the lift. There was some play, but not enough to alarm me. No noticeable vibration or problems with handling or stopping.

I went out today and put it in 4x4 for a little bit (needed 4Hi to get out of some loamy sand). I drove around the fire roads (gently) and noticed a weird howl when I got back on the highway. Figured I didn't have the hubs ids-engaged. Put in reverse. Same noise in reverse. Again, I didn't do anything today that I feel would have caused damage. Maybe I knocked somethin' loose?

Doesnt matter if it's forward or reverse. Left or right turns.

Just got home and crawled under it. Everything is cool to the touch: hubs, front pumpkin, entire front end, all U-joints & carrier bearing. Rear end is also cold, ecxcept the rear pumkin. It also had the fluids changed out around 5,000 miles ago. The only warm-to-the-touch spots were the output shaft of the Transfer Case and my rear differential (which was significantly warmer--normal?)

On the 'net to find D60 & swap parts. May need it sooner than I thought...

Thanks in advance for any help. In the meanwhile, I guess I'll go buy some wheel bearings. Cant hurt.

[madpogue]

Auto or manual hubs? Did you happen to notice, after you shifted to two-wheel, if the front wheel u-joints, front axle shafts and/or front driveshaft were turning?

[slepe67]

Auto hubs. It didn't seem to matter if it was in 2 or 4 wheel drive. It did go in and out of 4WD if that's what you mean.

My buddy has a 2WD OBS and swears it's the tires. His howls as well.

My wife's FJ Cruiser has the identical tires and it doesn't make any sound at all. Wonder if it could be noise transferring through the spring-eyes and through the frame? Sounds weird, but I read that in here someplace regarding another type of sound.

Regardless, I need new bearings up front, so I'll put them in this week and let ya know if it helped. If it doesn't, I think it MAY be the tires.

Thanks again!

[madpogue]

Originally Posted by slepe67

Auto hubs. It didn't seem to matter if it was in 2 or 4 wheel drive. It did go in and out of 4WD if that's what you mean.

The transfer case may have disengaged the front driveshaft, but if the hubs didn't unlock, then they'll still turn the axle shaft and, in turn, the front driveshaft. If one unlocked and the other didn't, then just one axle shaft will turn and the diff will spin open, and that could be the howl you're hearing.

[slepe67]

Originally Posted by madpogue

The transfer case may have disengaged the front driveshaft, but if the hubs didn't unlock, then they'll still turn the axle shaft and, in turn, the front driveshaft. If one unlocked and the other didn't, then just one axle shaft will turn and the diff will spin open, and that could be the howl you're hearing.

WOW, never would've thought of that!

I had it off road this weekend again. In 4HI and 4 LO. No change. Everything is cool to the touch. I'm going to install the new bearings this weekend & clean-off/inspect the hubs while I'm at it.

Question: when switching from 4x4 to 2WD, do I need to go in reverse to disengage the hubs? No owners manual...

Thanks again!

[madpogue]

Originally Posted by slepe67

Question: when switching from 4x4 to 2WD, do I need to go in reverse to disengage the hubs? No owners manual...

You don't _need_ to, but you should. When you switch to 2WD, the transfer case no longer engages the front driveshaft, so you're only driving the rear wheels. But the auto hubs don't unlock from the axle shafts until you reverse something like 20 feet.

If you try the above tests, and it looks like the either hub is not unlocking, or if you have any doubts, manual hubs are the best alternative.

[slepe67]

Originally Posted by madpogue

You don't _need_ to, but you should. When you switch to 2WD, the transfer case no longer engages the front driveshaft, so you're only driving the rear wheels. But the auto hubs don't unlock from the axle shafts until you reverse something like 20 feet.

If you try the above tests, and it looks like the either hub is not unlocking, or if you have any doubts, manual hubs are the best alternative.

I was on the fence about swapping hubs, but I really like the MANUAL idea a lot better.

I just got all my front end bits, will let ya'all know what I find. I'm sure it'll be fun!

[slepe67]

The howl got considerably worse, and I could FEEL it in the floorboards while driving.

I have a thread about how GREAT of a day I had yesterday.

It was the wheel bearing, passenger side front.