[ERM100]

I have a 97' F-250 4x4 with 7.3. I have been trying to find the source of this ratcheting/grinding noise when I make a left turn. Truck runs/looks/drives great except for this damn noise. It happens at all speeds and the noise coincides with the speed of the truck. It will do it in 4 wheel drive too. Its starting to drive me nuts, its not really loud but definitely noticeable. It sounds like its coming from the passenger wheel but its hard to pin point while driving. I have replaced the passenger side wheel bearings with no change at all. I also removed the warn manual locking hubs and still get the noise. I have tried messing with the 4 wheel drive and the hubs. Almost sounds like something is half engaging when the weight of the truck pushes on passenger wheel. I just bought 2 new u-joints for the passenger side axle, hoping that will fix it. Then I realized that the front driveshaft isn't moving unless I'm in 4 wheel drive. Can anyone please shed some light on my problem or at least point me in the right direction as to what I should be checking to try and pin point this. I don't want to just throw a bunch of parts at it. Any help would be much appreciated.

Thanks, Ellis

1997 Ford F-250 4x4
7.3 Powerstroke Diesel
230,000 miles

 

[Steve83]

Have you read this TSB?
http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=43265

Lift each front wheel by the axle housing, and check the BJs & WBs for looseness. Then put the rear axle on jack stands, have an assistant get it up to ~25~55mph while you crawl under with a mechanic's stethoscope and listen to the trans, t-case, d'shaft center bearing, diff carrier bearings, & wheel bearings.



If you still can't pinpoint it, either use something (I prefer an angle grinder with knotted cup brush) to spin each front tire up to speed (on jack stand, of course); or take it to a pro for diagnosis.

 

[DENNY]

Check the mounts for the left and right axle arm. They can crack and let the axle shift a bit. Check the shafts and all other parts for rubbing. Ford does not stock them so weld it up or get one from junkyard.

Do you have a limited slip rear end? Clutches could be not working right causing noise when you turn(recent rear axle fluid change/low fluid). I have chased trucks around a circle more than once trying to find where the noise is coming from.

My vote is for the rear axle.
DENNY

 

[ERM100]

It will only make the noise when the weight of the truck is on the axle's. I have checked the wheels with the jack under the axle. I could try putting front and rear on jack stands and turning the wheel. I have a feeling it has to do with the weight of the truck pushing on the passenger wheel but its worth a shot.

Thanks!

 

[bugman]

To try and isolate it can you have someone walk beside your truck as you drive it around in a circle in a large parking lot?

 

[ERM100]

Ok so today I went to empty parking lot and drove in a circle making a left. As usual the noise started right away. I noticed that when the weight of the truck is pushing hard(like at the bottom of an incline)the noise gets louder. You can feel it under your feet when its happening. I stopped the truck so it was facing downhill while the wheel was sharply turned left. Got out and checked everything, I one thing I noticed is that when I turned the front driveshaft I could feel a resistance, like it got tight at 2 spots while making 1 revolution. Then if I straighten the wheel out or turn it hard right the resistance goes away. Seems to me it would be the cause of the noise I'm hearing. Seems to be a transfer case problem. Not sure why turning the wheel one way would affect the T case but who knows. Has anyone driven their truck with the front drive shaft out? I would like to remove it and try to replicate the noise. I have a feeling that it wont make it with the shaft out.

 

[79jasper]

More likely a issue with the axle shafts. Look closely around the ujoints. I bet one of the ears is beating on the ball joint.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[DENNY]

If you have unlocked the hubs and transfer case in not in 4x4 than front driveshaft and axles should not be moving. The tightness you feel is normal in 4 wheel drive mode but not in 2 wheel drive.
DENNY

 

[Steve83]

Then I realized that the front driveshaft isn't moving unless I'm in 4 wheel drive.

...when I turned the front driveshaft... Seems to me it would be the cause of the noise I'm hearing.

:icon_rolleyes: :scratchhead:

 

[ERM100]

I removed the front driveshaft and took it for a spin. It is still making the noise so Im relieved its not the T case. It has to be in the front wheels somewhere. I bought a spindle bearing kit and I'm goign to take everything apart this weekend. Hopefully i notice something. Is it a pain to change the front diff gear oil of these trucks? Ive never done it, the rear is easy but the front looks like it could be a pain.

 

[madpogue]

The resistance you reference in post #1, that goes away when the wheels are forward, are a classic sign of front axle u-joints that need attention. Grease them if they're so equipped, replace otherwise. Spindle bearings may also be a factor.

 

[ERM100]

But if the truck is not in 4 wheel drive should that resistance cause the axles and driveshaft to move even when T case is not engaged? Like with the front drive shaft removed the axle u joints would not be spinning but the truck still makes the noise. Madpogue

 

[madpogue]

I don't know the exact science behind it, but if those u-joints are really bound, steering the wheels can cause the axles to rotate. I'm also thinking (just speculating) that if the spindle bearings aren't good, the free-spinning spindle could be causing the axle stub to rotate.

One simple test I know for sure is the one you described - if the axle shaft turns easily by hand with the wheels straight but not with the wheels steered left/right, I know I need to grease the u-joints.

 

[Steve83]

Steering can only cause the axles to rotate 1/4 turn at most, and then they stay in that position until 4WD is engaged again.

And sealed U-joints CAN be greased - they just have to be R&I'ed. But this problem is not from U-joints.

 

[DENNY]

If you have the hubs locked than the axles will turn without the driveshaft in. Did you have your hubs locked or unlocked during the test?
DENNY

 

[ERM100]

If you have the hubs locked than the axles will turn without the driveshaft in. Did you have your hubs locked or unlocked during the test?
DENNY

The hubs were not locked when I did the test.