Driveline vibration help

[rob h]

Most of you seen my straight axled 2003 2500hd chevy Silverado, it was regeared by a local pretty well known shop(even on pirate). It was geared with 5:13 motive gears and a Detroit locker. All new bearings and seals. they also regeared my dana 60 also. I changed the fluids after 500 miles and everything was good. I put about 3500 miles on it after that and still good. One day in town I smell gear oil when I was getting gas, I looked and seen around the pinion all wet. I drove it home about 5 blocks and as drove up the street I heard something like a rock kick up(pinion nut). I stopped at the corner the yoke fell off. The rear of the shaft hit the ground, I looked under, slid the shaft out and stuck it in the truck bed. Locked the hubs in and drove about 100ft to my house. I walked down the alley and picked up the washer and nut. It really didn't vibe or make noise before that is what gets me.

So I removed the cover and the gears looked fine and the oil didn't have metal in it. I put the yoke back on and tightened it. The axle seemed to spin ok and no noise or vibes. Until the last month I can feel after 40 mph the vibe, it gets worse at 60 and calms down after that. So I pulled the shaft today and put new spicer joints in it, dropped it of at a driveline shop and it was out .053. They retubed it and I put it back on, vibes are still there like I did nothing. The slip yoke bushing doesn't seem to have play in the 241, the 241 has the t-case saver also so that shouldn't be the problem.

Can the slip yoke bushing even cause vibes if I cant feel any play..?....the pinion doesn't seem sloppy either....any ideas..?...can pinion bearings do those kind of vibes...?

 

[AR_K5]

When checking for play were you sure to chock the wheels and put it in neutral?
Have you checked for a thrown wheel weight, or had wheel balance checked?
Did you remember to unlock the front hubs?

 

[rob h]

When I checked for play the trans was in neutral but the case was in 4 hi, when I tried to wiggle the slip yoke I didn't feel anything. The rear axle was on the ground when I checked the rear. I guess I should jack up the rear off the ground and check it, maybe it had tention on it. The hubs are unlocked for sure.

 

[AR_K5]

When I checked for play the trans was in neutral but the case was in 4 hi, when I tried to wiggle the slip yoke I didn't feel anything. The rear axle was on the ground when I checked the rear. I guess I should jack up the rear off the ground and check it, maybe it had tention on it. The hubs are unlocked for sure.

Or just put the Tcase back in 2wd or neutral so there is no possibility of tension on the drive shaft. Picking the rear tires off the ground will let you get an idea of how much slack is in the rear diff.

 

[rob h]

Or just put the Tcase back in 2wd or neutral so there is no possibility of tension on the drive shaft. Picking the rear tires off the ground will let you get an idea of how much slack is in the rear diff.

It has a Detroit locker it it so that might be a little hard to do.

 

[AR_K5]

What's that got to do with anything.
I was talking about slack in the ring and pinion, it won't be like putting a dial gauge on it but you can tell if its really sloppy.

Another thing you can try is flipping the rear u-joint (or both) 180°
It may not help, but it never hurts to try.

 

[rob h]

I was just out and flipped the shaft around, I was prob doing that as you typed it..lol... same vibes that way. I checked all the adapter bolts and they are all tight. I tried again with the back jacked up and seems all tight, I cant feel any play there. I push up and down on the slip yoke and the only thing moves is the rubber trans mount. I wiggled the slip and can feel the slightest bit of play, that's in neutral and I slid a spare yoke in to see.

Would the slip yoke bushing cause a huge vibration without leaking..?

 

[AR_K5]

I was just out and flipped the shaft around, I was prob doing that as you typed it..lol... same vibes that way. I checked all the adapter bolts and they are all tight. I tried again with the back jacked up and seems all tight, I cant feel any play there. I push up and down on the slip yoke and the only thing moves is the rubber trans mount. I wiggled the slip and can feel the slightest bit of play, that's in neutral and I slid a spare yoke in to see.

Would the slip yoke bushing cause a huge vibration without leaking..?

I want to say yes, my dad is having the same trouble with his S-10. Good U-joints, rotated the shaft. Shakes like hell at around 55+, i think his output shaft is moving (it is leaking).

 

[rob h]

Mines not leaking tho, from what ive read that's the first hint.

 

[Blue85]

Does your 14B still run a crush sleeve? You may have messed up the pinion bearing preload. Does the vibration change whether the rear is under drive/coast?

Another possibility is that it's not the rear end at all, but you lost wheel weights, chunked your tires or something else. Also verify that the T-case is really going into neutral and you're not spinning the front shaft. They are often loose in the slip joint and like to shake.

 

[rob h]

Yea still runs a crush sleeve, I'm going to change the slip yoke bushing and if its still there look at the rear and prob re set up the pinion with new bearings. It vibes more when on the pedal and less when off but its still there. These tires were spin balanced about a month ago. I'll check em but I doubt that's it.

 

[rob h]

I pulled all the tires off and one was out 3oz but that's about it. I pulled the rear shaft back off to check the pinion, That seems to be pretty good. The ubolts are all tight also. Im going to swap the tailshaft bushing tom afternoon, its only going to be about 5-10 degrees so it will be cold.

 

[496truck]

Is the rear shaft a CV style? If so, the center ball may need a rebuild. I've had this happen to me before, can't find anything wrong with it till you take it apart.

 

[rob h]

The rear shaft is a 4 inch straight tube, a joint at the axle and slip yoke front. Rear springs have angle shims in the pack for the proper angle. The shaft is new, was just returned/balanced and new spicers put in. All 1410.

 

[496truck]

My next suspect would be the diff. There is no reason the pinion nut would have backed itself off. Something is wrong there.

 

[rob h]

My next suspect would be the diff. There is no reason the pinion nut would have backed itself off. Something is wrong there.

That is exactly what I was thinking, after I do the slip yoke bushing im going to take a look at that.

 

[rob h]

Pulled the cover off and the axles out today. There's no preload on the bearings and no backlash. The pinion rides on the edge of the ring gears teeth. The gears look fine ,So I ordered a new master install kit and am going to do it all over again. I shouldn't say I'm going to do it..lol..a buddy of mine is a master tech at the gm dealer. He's going to take care of it. Hopefully that fixes the problem

 

[496truck]

Sounds like you found the problem. Keep us posted.

 

[rob h]

Still in pieces, I ordered my master install kit from northern auto parts , the new yoke from dennys driveshaft. The install kit came but for some reason my yoke never came. The tracking # went from out for delivery to n/a. I called dennys and they called fedex to find the package, hmmm imagine that my yoke is in fort worth texas...lol. Dennys has great service and took care of the mess up immediately. I called around and about 35 miles away they had one in stock a little expensive tho at 150.00.

I got a phone call hours later that the pinion old bearings just about fell off when he was removing them. He said its not right at all. So now its order a new ring and pinion. I called randys last night and they could ship it to me for Monday. So everything is cleaned and all pulled apart. It will be back together on Tuesday I hope.

 

[rob h]

The outcome is the vibes are gone. The gear pattern came out almost perfect. I drove it around and there is no gear noise and its better than I thought it would be. I have about 800.00 in it but everything from bolts, yoke, seals, bearings, gears is new. I put in gm synthetic gear oil also.