Noisey fwd

Working some bugs out of my "new" 71 cj5, freed up a sticking hub, when it's in 4wd it's got a fairly heavy sqwonky honk kind of noise from about 10 to 14 mph, then it's gone. It sounds like a shaft shivering in a dry bushing, like a dry input shaft bushing noise but heavier. With the hubs in but TC in 2wd no noise, hubs out and 4wd in there's no noise, but couple it all up and it does it's trick. Nothing obvious loose or leaking, do have some slop in the rear driveshaft slip joint and it's a real short one too, it's a T-18 and a D-18. Not in much of a panic to tear into it yet, just thought I might run it past you guys for the sake of conversation, if nothing else.

 

Driveshaft u joints would be my guess. No real stress or strain on any of it until it's all "coupled up." So, it may not be evident until then. I've never really heard any noise from axle shaft joints until turning, unless they are completely spent and then, the problem is usually very obvious.

 

Well, it makes more noise on mine when I put the 4 wd, but all parts are well oiled. Greased;

you can add some oil checking the levels, that is easy. Grease too.

But to make more complex work, I am not specialist, those on the forum will tell you (and me).

There are many reasons for noise, these are not new cars, bearings, tired parts...

 

are knuckles full of grease & oil . aka pudding

 

id be inclined to pull off the axle end of the driveshaft to check the u joints make sure theyre not locked up

 

Try greasing the driveshaft u joints, one at a time, and see if each attempt quiets the noise. I've even sprayed penetrating oil on the u joints to quiet it down so I could determine which one was bad. If the noise remains afterwards, I'd then consider going deeper and into the axle shafts/knuckles.I tend to start with the cheaper, easier stuff and hope that I find the issue before going after the more difficult, more time consuming and sometimes more expensive areas. Start simple unless you know where the issue is.

 

Okay, I'll check that stuff this evening. Have no reason to think the knuckles don't need serviced.

 

Put the t-case in Low with the hubs locked. If the noise gets noticeably worse, it may be the intermediate shaft in the t-case. I've replaced two of them, but I noticed the rubbing sound mostly in low range first. If it is worn long enough it will make a rubbing/ chafing sound in hi range too. It is possible to replace the pin and rollers without pulling the t-case, but it looks to be a PITA. Just another possiblity to consider.

 

Greasing the rear driveshaft nearly eliminated it, I'm going to drop it out to feel the U-joints, probably go for a ride Toronado-style to see how the front feels by itself. It only makes the noise between 10 and 14 mph, doesn't care which gear your in, or high or low.