Vibrations - NP208 fail?

[dieselponyexpress]

I qoute this from an old post from the 73-91 K5/Suburban/Truck, -Section, originally belonging to a NP241 issue:

About the Tcase, if you grab the driveshaft and try and shake it up and down is there movement? if yes then you have a bad bearing where the slip yoke goes in.
This is the only part I can think of and it's not uncommon.

Is this problem also very common for a NP208?

I do have bad vibrations and have minor up and down play at the slip yoke (NP 208). Is the bearing at the tailshaft mounted in a way that I don't have to remove the complete tcase?
When removing the rear driveshaft and driving in fwd, there are absolutely no vibrations. Same when driving in 4wd (rear driveshaft installed). I swapped driveshafts from another CUCV with no avail. So I'm thinking of a bad bearing on the NP208 rear output.

Any help?

Walter

 

[apache]

Are you sure you have the D/S yoke angles OK with your shackle flip? the 3 trucks Ive had with 208`s always had a bit of play without issue,but its hard to guess how much is a little on your truck. .

 

[dieselponyexpress]

Thanks for your answer, i too thought about driveshaft angles, but the shakings became worse every mile (new spicer joints already installed). Right after installing the shackle flip and a 6* shim the vibrations weren't there iirc.
Also, would driving in 4wd help with an incorrect angle?

Walter

 

[apache]

Id think the bearing would have to be so bad the seal would be shot from the slop and leaking like a stuck hog. The only things that come to mind are yoke phasing is off or is it possible you took a rock or otherwise that bent the DS. You can use a make shift pointer or better yet a dial indicator to check runout of the DS in front back and middle.

 

[dieselponyexpress]

Vibrations - NP208 fail? UPDATE!

Like mentioned before, i installed a driveshaft from another cucv and no difference.
Pulled the tailshaft today and the rear shaft bearing felt out. I rebuilt the tcase some time ago, but don't remember of that particular bearing. Is it supposed to be pressed in? From looking at the bearing, it seems a snap ring should hold it in place. But the race/seating is round and smooth without any signs for a snap ring.

If this bearing came loose, it sure would explain the vibrations!

I made some pics for illustration and hope so will chime in.

 

[dieselponyexpress]

Update

Had the loose bearing reinstalled with red loctite but the vibrations didn't go away. The truck became undriveable because of the shaking plus there was an oil leak somewhere.
With tcase in the truck I removed the tail housing and looked at the bearing. It was still in place and looked good. Without the housing/bearing the output shaft has considerable play when moving it around, pretty normal i think.
When sticking a finger inside the oil drain hole, I can feel lots of small metal parts and shavings (NOT pretty normal). Something seems to be broken inside.

But i'm still not in the mood to open the case.

So, I removed the case and put it away for now.

After removing and cleaning the adapter I discovered the cracks on it (no wonder dexron poured on my driveway).

Wondered what caused this to happen? Is it the result of the vibration or the cause? My tcase rubber mounts are bad, but not that bad i think. Just 25 years old and oil soaked . . .

Finally there's no more reason for my mostly rebuild 205 not coming into use.

Walter