VIDEO ATTACHED.Front Drive Shaft/Differential odd movement and loud clunking/clicking

[redrunn]

Hey Guys,


First off, here is the video. https://www.youtube.com/watch?v=HZtOnUdUAoY

Was like this when I bought the truck. The 4wd did work, but there was a clunking sound, associated with a rubbery squeaking sound as well. When I finally got under the truck and lifted one rear wheel alone with one front wheel, I found that the diff was shaking violently on every rotation of the crank. As you can see, my pinion seal is toast as well.

While doing a diff drop, I spun the drive shaft and this is what I found. I don't feel any play otherwise. The truck was already on stands during the video, the jack is just there as a fail safe, and to support the diff.

Please advise. https://www.youtube.com/watch?v=HZtOnUdUAoY

 

[dogojoe96]

First of all, do you have selectable hubs or the add flanges? Second what is the condition of your cv axles? Are you running on some cranked up torsion bars? Or was the truck on the jack?

Before you can isolate the problem it will really help to pull the driveshaft, by your video the way it was jiggling the transfer case as well is disturbing. Did you happen to spin the driveshaft with the differential mounted solid ( before or after the diff drop spacers)

 

[Darrie]

Pinion seal gone - that bounce will have chewed it out. Gearbox out of 4wd enables you to free turn the front shaft, and as ADD disconnects the front shaft from the diff that should really isolate the issue to be either the shaft itself (bent or frozen extension), the front or rear universal joints on the front drive shaft , or something weird happening in the diff up to the ADD section.

Check the universal joints each end are in the exact same position ( Ie the Transmission output U is identical to the front diff input U so that they are mirrored). Then try disconnecting the front drive shaft (mark the position so it goes back on to identical spot) and spin the front diff input flange - see if any bump. If so drop the diff oil to see if any bits. If none check out your two front universal joints on the shaft are rotating without binding on an angle, and also ensure the shaft extends in and out and not locked solid.

 

[redrunn]

Truck has a light crank on the torsion bars, and has ball joint spacers up front. This problem was there before the lift.

The truck has add, and this video was taken without 4wd enganged, vehicle off and the front differential hanging from the front cross-member mount.

The motion of the transfer-case itself is minimal, the big problem is the diff itself swaying that violently. When diff is mounted, the problem still exists, but it is accompanied by loud clicks, and a rubbery squeak.

My first thought was that the CVs are bad. I replaced a leaking shaft, and checked to see if they bind. With the diff drop, they do not bind at all.

So to summarize, the diff just shakes per turn while it is mounted. Every turn is associated with a loud click. When the diff is unmounted, we see that it is being pushed down somehow. This is where I am lost. I'm not sure what is pushing it down. Would a bad U joint cause this? The pinion seal blowing is a good indication of where the stress is.

I want to remove the shaft, but I want to hear what you guys think first, and what my next steps should be.

First of all, do you have selectable hubs or the add flanges? Second what is the condition of your cv axles? Are you running on some cranked up torsion bars? Or was the truck on the jack?

Before you can isolate the problem it will really help to pull the driveshaft, by your video the way it was jiggling the transfer case as well is disturbing. Did you happen to spin the driveshaft with the differential mounted solid ( before or after the diff drop spacers)

 

[redrunn]

roger that

Sounds good. I'll do that as soon as possible. You are 100% on everything. The seal went bad because of that stress. The U joints all look bone stock, and don't look to have been greased in a few years. The nipples are corroded as well.

If it is the joints on the shaft, do you guys recommend buying a used shaft on ebay? The local wreckers want 120ish for one, and chances are its a rusted out shaft. I could get a cleaner shaft from the states.

Or should I pay a shop to rebuild the shaft? I don't have a press with me. I can buy 3 U joints for about $90 from rockauto. I've read about a center ball for the double cardon. I'm not sure what this is, and I can't find the part either.

Any advice?

Pinion seal gone - that bounce will have chewed it out. Gearbox out of 4wd enables you to free turn the front shaft, and as ADD disconnects the front shaft from the diff that should really isolate the issue to be either the shaft itself (bent or frozen extension), the front or rear universal joints on the front drive shaft , or something weird happening in the diff up to the ADD section.

Check the universal joints each end are in the exact same position ( Ie the Transmission output U is identical to the front diff input U so that they are mirrored). Then try disconnecting the front drive shaft (mark the position so it goes back on to identical spot) and spin the front diff input flange - see if any bump. If so drop the diff oil to see if any bits. If none check out your two front universal joints on the shaft are rotating without binding on an angle, and also ensure the shaft extends in and out and not locked solid.

 

[redrunn]

Fixed

The problem was that the driveshaft slip yoke was absolutely rusted solid. Seems like the previous owner of 24 years never really slipped (pun) it into 4wd. The yoke was rust welded badly in one place, and had rust all around it.

This would have been avoided if he had some knowledge about cars. He did take it to be serviced at scheduled intervals, but the *******s at quick lube, penzoil etc. knew the old man wasn't going to crawl underneath his car to see if the slip yokes were lubricated. The practice carried on for 24 years, the slip yoke was never lubricated.

When I went to a pit stop to get my service done, I'd noticed when I got home that none of my fittings were lubed, except the obvious u-joint. I called back to speak to the manager, and he claimed that my chassis was sealed. I laughed and told him I'll get into the pits with him and point out every single one, which I did.

LUBE YOUR JOINTS GUYS. Further, I didn't want to throw 100 into a junkyard shaft, so I just disconnected the shaft at the diff, and beat it inward with a hammer, and reconnected it. Noise gone, all is well.

Hope this helps.