Driveline clunk noise

[MOLON LABE]

In 1985 I special ordered a 1 ton 4x4 just the way I wanted it. Not a dually, 454, 4-56 gears, all the bells and whistles.
It was a great truck except it had the "factory clunk" from day one. When putting it in gear, brake pedal pressed, it made a loud metallic "clunk" like the u-joints were gone but it wasn't them. I took it to our two local dealers, both said tough luck, it's a normal condition, nothing was wrong. I complained up the chain of command but no luck.
I sold the truck a few years later.
Fast forward to now. Last year I bought a creampuff 1990 suburban 1500 4x4, 5.7 with only 30,000 original miles and it has the same noise.
I have since heard that packing grease somewhere in the driveline would fix it for a while, is this true and how and where do I do it ??
Also, is there a permenant fix for this ?
Thanks in advance.

 

[Brocky]

Have you took a notice to how much backlash you have in the rearend. Don't know if this could be your problem.

 

[MOLON LABE]

I'll look into the backlash issue but best I can tell it's happening up around the yoke and tailshaft housing.
Anyone else have any ideas ?

 

[jekquistk5]

Check your Tranny mount, as well as your motor mounts. When you put it into gear even with the brake on if the mount is bad it will move and go clank. My mount looked fine, untill I loosened it up and got a good look at it. good luck

 

[gone huntin]

I have the exact same truck and mine USED to do this. I finally found that dielectric grease (very thick) on the slip yoke splines worked extremely well. Since then I have installed a H.A.D. CV equipped driveshaft and no longer have the problem.

 

[MOLON LABE]

This is the "fix" I have heard about. Putting grease on the splines at the slip yoke. Thats where my noise is coming from.
What's the procedure for this operation and is there a prefered brand or type of grease that works best ?
How long does this work before it clunks again ?
The HAD CV joint shaft, where can I get info on it ?
Also, I have heard that GM has a nickel plated yoke that fixes this problem on newer models. Is there a fix similar for the older trucks ?

 

[MattK]

depending on which it is, its also possible that there is also slop inside the transfer case.

 

[gone huntin]

This is the "fix" I have heard about. Putting grease on the splines at the slip yoke. Thats where my noise is coming from.
What's the procedure for this operation and is there a prefered brand or type of grease that works best ?
How long does this work before it clunks again ?
The HAD CV joint shaft, where can I get info on it ?
Also, I have heard that GM has a nickel plated yoke that fixes this problem on newer models. Is there a fix similar for the older trucks ?

H.A.D. I didn't have anymore clunks after I used the dielectric grease, but due to a vibration, I installed the cv shaft a month later. Personally, I used some Motorcraft dielectric grease just because that's what I had. I used a big flatblade screwdriver and spread the grease out inside the slip yoke.