Front end clunking (yes, another clunking post)

[kevinv]

Hello,

I'm getting clunking noise when in 4wd. I'm assuming this is coming from the front end. It happens when the front hubs are locked and in 4wd. It doesn't happen with locked hubs but in 2wd. It also seems to happen under load, its worse when accelerating and lessens when letting off the gas.

I was attributing it to a transfer case problem until I read some of the posts on clunking. Seems it could be a drive shaft problem. The truck has been lifted but the driveshafts weren't replaced. You can see a lot of the yoke (sorry if I don't have the terms right). I have been told the driveshafts should be replaced because they are over extended.

Is it more likely to be the driveshaft/u-joints over a transfer case problem? Any other suggestions for determining the problem would be appreciated.

Thanks for any help,
Kevin

 

[xcntrk]

Probably front drive shaft as you've diagnosed. Does the pinion yoke or anywhere else in the diff leak fluid or feel overly hot after operation? Best bet is to climb under there with a pry bar and start poking around looking for slop or something with excessive wear. Check the front pinion yoke, ujoints, d20 front yoke, etc.

Good luck

 

[DirtDonk]

You could remove the driveshaft and drive it in 4wd with the hubs locked to see if it still makes the noise.
Unfortunately, that's not a 100% check (though it's probably 95%) since it also changes the dynamics of the front end as the front is not longer acting under acceleration. But it's worth a shot.

The word you're looking for is "slip joint" or "splines" for that part in the middle that would be extended.

Just how high are you lifted though? It takes quite a bit sometimes to really over-extend a driveshaft. With that though, there is also the angle of the pinion that can cause trouble. Did you install offset C-bushings when you lifted it? If so, are they on correctly?
If they're on backwards, your differential pinion yoke (the part on the diff that the u-joint clamps to) will angle above the driveshaft. If they're in correct, your pinion angle should be slightly lower than the centerline of the driveshaft.
Of course, if they're on backwards, it'll drive like crap too! Wandering all over the road and acting really strange when you accelerate and decelerate.

If it does turn out that your drivshaft is either worn out or overextended though, at least they're easy to buy or have made. Not easy as in "cheap", just easy as in, "readily available" for different lengths.

Good luck. All sorts of things click in a 4wd. Hope you narrow it down before spending any money. Hubs, axles, u-joints, slip shafts, bearings, all can click. Maybe you just need to lube the joints?

Paul

 

[kevinv]

Thanks for the replies. I think its a 4 to 5 inch lift, I didn't do it, it was done by the previous owner. I need to take a closer look underneath to see what I can see. I'll reply back if any further questions come up.

 

[66broncoguy]

Are you running a cv joint at the transfer case? I ask because when I had 5" springs in the front of my 66 the angle on the front shaft was more than the cv would allow so it clunked. They will clunk if the center pivot in the cv is worn out also.

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