np208 loud grinding noise/hot tailshaft

[CherryK5]

So after my shackle flip (only gave about 3") my np208 has had a LOUD grinding noise during deceleration or when i put my trans in neutral and after getting home I was messing around and felt the tailshaft and its hotter than a two peckered owl.

Could it maybe be a bearing?

This thing sounds like its eating itself alive. And its my dd so I need to figure it out.

Half assed video in a minute.

 

[Fordum]

Not sure what the problem is, but damn, I like your visual.

When you lifted it, how was your spline distance?
It might be not engaged all the way and slipping.
Either way, heat is friction, and damage occurring.

Your best bet, is to drop the rear shaft at the transfer case, don't forget the wheel chocks, put it in neutral, and turn the shaft and wiggle it, feeling for play or grinding.

 

[CherryK5]

Not sure what the problem is, but damn, I like your visual.

When you lifted it, how was your spline distance?
It might be not engaged all the way and slipping.
Either way, heat is friction, and damage occurring.

Your best bet, is to drop the rear shaft at the transfer case, don't forget the wheel chocks, put it in neutral, and turn the shaft and wiggle it, feeling for play or grinding.

Plenty of spline engagement only 3/4" less than stock.
and there was no play with it on the ground. I'll put it on the lift and check it out.

 

[CherryK5]

http://static.photobucket.com/playe...albums/h187/kx519/2011-08-14_20-22-25_930.mp4

 

[Fordum]

Well, unless one of the U-joint bearing caps was about to go and the extra angle finished it off and the heat from that is causing the tail-shaft to get hot too, its almost got to be a tail-shaft bearing.

Bearing often don't wiggle until just before they come apart, but you can usually feel or hear a grinding when you turn it.

 

[CherryK5]

So it might actually be the rear end. No chewed up teeth or any unusual wear. But it spins freely for about 2 3/4 turns and then stops and wont spin any further without a bit of force

Video in a few

 

[Hogback Fabrication]

Who's shackle flip?

 

[sweetk30]

after the flip install did you happen to recheck drive line angles on the driveshaft ?

most guys need to readjust them or the shaft will bind the u-joints and self destruct.

 

[CherryK5]

after the flip install did you happen to recheck drive line angles on the driveshaft ?

most guys need to readjust them or the shaft will bind the u-joints and self destruct.

I cut my old ones to make a home made shackle flip. But at 3 inches it shouldn't bind should it? I can.snap a.pic when its on the ground.

The r&p bind int the same spot every time. Pulled the.pinion and checked the bearings and all the teeth. They look fantastic. Ring gear is the same story. But it binds in the same spot every time.

http://static.photobucket.com/playe...albums/h187/kx519/2011-08-14_21-49-26_227.mp4

 

[CherryK5]

Here are the only pics I shot on the ground earlier. I'll pull the add-a-leaf and overload to bring it down a little tomorrow and see if that helps any.

Never figured out the rear end. Any suggestions before I put it back together?

 

[Fordum]

You say the rear end binds at the same place each time? Try turning the wheels to see if you hear anything there.
Sounds like a pinion problem. A ring gear would not show up each time, since takes longer than one rev to get to the same place.

Come to think of it, so does the axle. Its got to be a tooth or bearing on the pinion. Look close between the teeth for a foreign object, and spin the pinion in its housing feeling for a rough place.

Still wonder what is going on with the tail shaft.

 

[bot0611]

hmm... i doubt drive line angles can caus this... put the have you turned the d-shafts by hand??? if not do it and listen if theres any noises in the inside.....and go from there.

 

[Fordum]

Hang on, you did disconnect the driveshaft when you were turning it and it was binding, right?

If the driveshaft is still hooked up on both ends, then the binding could be in the rear end, the transfer case, or a frozen U-joint cap.
Any one of them could cause a freeze up at the same place each time.

 

[CherryK5]

Alright. What I've done.

Pulled the pinion from the housing, spun it and checked every tooth and all the bearings including the one in the housing. (14bff)

I checked every tooth on the ring gear for any debris or rough spots. Spun it slowly to feel if anything felt rough. Everything checked out.

I never messed with the settings on my diff so its set up correctly.

Checked out the u joints for any binding or play. Not a damn thing...

So since this happened after the shackle flip im going to pull a leaf and the over load to drop it down an inch or so. (It sits ass high anyways.)

Any other suggestions are welcome and incouraged.

 

[CherryK5]

Upper driveshaft angle.
Looks kinda steep after looking a second time. i have some 1x2 steel i can use to do a tcase drop,

 

[sweetk30]

first off BEEF UP THE HOME BREW FLIP doing it that way makes the hanger real week on the outside edges. and there is much better ways of doing a home brew flip. front hanger for rear springs from 2wd frame i used ( pic ) and diy4x usdr shackles. ( note not finished yet. will get more bolts )

also search and read up on tcase drop info.

 

[496truck]

Hey! You didn't notice that the rear axle pinion points up to the t-case and the output shaft of the t-case points straight back to the rear bumper. That's bad u-joint angles. Dropping the t-case is not an option cause you couldn't drop it far enough.

There's your problem. Ask me how I know...

You have 2 options but only one will work really...

1. Get shims and point the axle pinion down and more level with the ground. This will equal out the u-joint angles but now increases the working angle of both joints causing them to wear out much faster and easy to break under load.

2. And really the best fix for this, leave the axle where it is and get one of these...

 

[CherryK5]

Yeaaaa. I was afraid of that. How much did that run you?

 

[496truck]

$350 at a local driveshaft shop. New tube, new rear yoke, new slip yoke, used/reconditioned CV, built, welded, and balanced. Oh, and all new u-joints. Works perfectly.

 

[CherryK5]

$350 at a local driveshaft shop. New tube, new rear yoke, new slip yoke, used/reconditioned CV, built, welded, and balanced. Oh, and all new u-joints. Works perfectly.

so i would probably be able to re use my tube and save a few bucks?