Hi all, I've got my 81 f150 (4x4, 4.9, reg cab short bed) making a noise from somewhere in the front end. It makes a loud "clang" when starting from a stop, then a metallic clicking when under load. Sounds like it's coming from under my feet or a bit up front of there. I thought it was a driveshaft u joint but they all feel good, and the clicking may be too slow for it to be that. I've got some rotational play in the front axle, which is probably where the noise is coming from, but the two outer u joints are brand new and it doesn't appear to be that third one in the middle either. Does this mean it's a problem with my gears in the pumpkin?

 

Is this in 2wd or 4wd? With the hubs locked or not? It makes a huge difference in diagnosing, and you've not told us any of it.

Here's the testing I would do:

• 2wd & hubs unlocked: This tests the rear driveshaft, u-joints, and rear diff
• 2wd & hubs locked: This only rotates the front drivetrain, but not under power
• 4hi & hubs unlocked: Tests the front driveshaft's u-joints, but still not under power
• 4hi and hubs locked: Tests everything

Let us know what you find, but tell us under what conditions you get noise and what the noise is.

 

It seems to be happening in every scenario, but it does sound like it's coming from the front, sort of under my feet. It might better be described as a chirp than a clicking. It's been sitting for a week and I just went out and drove it and could not replicate the clunk.

 

Chirping is most likely a Ujoint.
You cant really look at them to see if good or not you need to drop the shaft and flex the joint by hand for any binding.

Have you also checked all front end suspension bushings? Could be one or more are bad and you are getting metal on metal contact causing the "chirp".
Dave ----

 

The bushings are not great but the noise is so closely tied to speed and load that I feel like it's not that. My original diagnosis was u joints so I may just pull the shaft and change all the u joints, not a huge job. I didn't immediately see a way to get the front driveshaft off, does it become more apparent after I remove the rear?

 

I have not been under a TT 4x4 front end but cant see it being much different than any others on pulling the front drive shaft. Undo at transfer case & front diff and it is out.


I would guess it also has a slip joint as does the rear (or does the rear slip into the TFC?) may want to look at that slip joint for wear.
Dave ----

 

Both of mine have slip joints, so like Dave says, pull the u-joints and it comes out.