Just not sure, and am looking for input from others who may know better than I.

My rearmost drive shaft u-joint is bad and has slop. I've been having vibration for about 7-8 months, but just started hearing a noise within the past week, especially when taking off with a load on the drive line (up hill or heavy acceleration. The vibration has not gotten worse, just that the noise has just begun to show itself.

I have one u-joint which is OE and has 275K miles on it, and it seems to be OK at the moment. The other two (including the rearmost unit) both have about 100K miles, as does the center support bearing.

Just because I don't want to worry about anything, I'm going to replace all three u-joints with Moog Super Strength units, and will also replace the Center Bearing with a new Spicer unit... just because I can and don't want to be pecked to death with multiple failures in the same drive line. I ordered the Moog joints because the only Spicer joints I could find were for the 4wd configuration.

That's the context... here's my question...

The parts are on order and won't get here for several days. I've been driving the truck like it is at about 1500 miles monthly. What do you guys think about me continuing to drive the truck for another week before getting the joints and bearing installed? I know it's a guess... just looking for more perspective.

 

Can you give us visual perspective of the situation? My definition of slop might be different than yours. If it has enough, or wears enough, to allow the needle bearings to fall out, serious damage could result.

 

I have an 82 Toyota 4x4 that dropped the front end of the drive shaft. I was lucky there was no seams in the road. I was young then and could have sworn it would have made it till the next week. Scary stuff! Glad I didn't hurt anyone. Recently, a semi dropped his entire driveshaft in front of me and it turned just right as I went over it and made it without incident.

 

You've touched the issue I was considering, Roland... I believe there is enough movement to where the needles have begun to fall out.

That being said, my decision is made... I'm leaving it parked and up on stands until I can get the new joints and bearing installed later this week. I certainly don't want the rear end of my rear drive shaft coming loose while I'm running down the road at 60-75 mph, sling out sideways, then and potentially have the drive shaft flip the truck over.

THANKS GUYS!!

 

A buddy of mine had a 93 F-250 gasser with a front U-joint that was so shot you could hear him rattling up the street 3 blocks away.He BRAGGED about it for 2 months....Saying, " I'm just saving my money, so I can do it myself"..... One day the truck came home on the back of a Flat Bed with a giant Gash running from the cab extending 4' down the bed. and the drive shaft was still sticking straight up in the bed....Looked like a flagpole. I took a picture of it, and of course I can't find it now. We didn't have the heart to laugh. To Painful...Made his wallet hurt.

 

Roland It's funny you say that because I have a friend locally that will call and ask questions like do I think it is bad and by the time he thinks things are going bad it is always WAY worse. And on the other hand some guys freak out when there is nothing wrong.
So that is a valid question.
When I was a punk kid I had a '69 Courger 351ci/ 4speed with a BAD front u joint and I side stepped the clutch....
Well I thought the drive was going to come thru the floor before I could stop.
Tore up the driveshaft & yoke and broke the trans case too.

Good call Pete ! Better safe than sorry. I also agree with just doing all of them and C.B Now if you can spare the money I would also have it balanced since it 275k on it and there have been cases where the rubber damper on rear shaft starts going bad. If that happens it would be really hard to tell from the driver's seat. But a guy doing the balancing would be able to tell.

I shouldn't say anything but I have 217k on all u joints except the rear one and I have a slight vibration. No physical movement in the u joint I can see or feel YET. But the time comes I do plan on replacing all with Spicer life 5-801X u joints and Spicer C.B and have it balanced.

 

I surely wouldn't.

Don't risk letting $100 in parts turn into $2000 parts and labor.

 

One more thing which I may yet discover is in the rear end. Two observations (includes a new one not yet mentioned)...

1) The noise I've been hearing has been sort of a rotational chafing sound, which I have thus far been assuming to be from the shifting of loose needle bearings in one or multiple cups in that rear-most joint. Again, this noise only occurred during what I call a "loaded" acceleration from a stop - either accelerating up a steep incline or a fairly hard acceleration when turning to the right. This is not a new observation, but just more thinking on my part regarding the "noise" in light of seeing the u-joint movement.

2) When looking at the joint movement, I think I also noticed some shaft movement in the yoke on the rear differential. I KNOW that the bottom half of the differential and axle have a slight coating of oil, but it is very slight. I had been assuming thus far that this oily coating had come from my leaking turbo pedestal which I replaced back in January of this year. I have no oil loss showing anywhere else at all, and had been thinking that this oily film had simply not yet worn off from the travel miles I've put on the truck since the pedestal replacement. The oily coating does not really look "fresh" and is not "wet", but being as thin as it is, it could be a fresh leak from an "oozing" situation.

Below is my QUESTION from the above two observations.

Could the noise and oily coating be sourced from low gear oil level in my rear end as a result of a worn seal at the input shaft hub?

 

Real possible Pete. The odds are that the pinion bearing is going, getting enough slop to cause the seal to leak, and possible noise too. Speaking from experience....
But I think the bearing and seal can be changed pretty easily while the driveshaft is out, from the front.
Good luck!

 

I guess I'm going to first try just the u-joints and carrier bearing and see if the noise goes away. If not... I know where to look for the next culprit.

 

Just called my local rear end shop, and they're only going to charge about $10-$15 to swap out my carrier bearing, but that's with me taking the drive shaft and new bearing to them.

 

Sounds like a good deal to me. You'll avoid their markup on the new bearing, for one. Also, pulling a driveshaft takes less than ten minutes. Most shops charge a minimum of one half hour labor though. So you'll save yourself some money there, too.

 

BLOCK BOTH SIDES OF TIRES before removing driveshaft, unless you have it lifted on jack stands !!

 

I just had my driveshaft slip joint replaced, new u joints and carrier bearing and balanced for 350 bucks. Best money I ever spent. All driveline vibration gone.

 

Believe me... after forgetting to use chocks one time about 5 years ago, I'll NEVER forget again!!

This time, though, the truck is already on two stands in the rear, and I'll be putting two more up front so I can do a full four corner detailed brake inspection while I'm waiting on the parts for the drive line work. I've been hearing some brake scratching noise when they get hot, but otherwise they are quiet... been like that almost since day 1 when I did the frozen rotors and new Hawk pads up front last summer, but it seems to be getting a tad worse... probably a slide pin which may be sticking a little when it gets heated up.

Costs...
1) the carrier bearing and three u-joints are $125
2) the center bearing R&R will be another $15
3) Balancing the drive shaft... $40 each... would probably only do the long one
4) The pricing for a new pinion shaft bearing and seal will run me about $50-$60, if required
Total Max out the door should stay below $240 if I have to do the new pinion bearing and seal, and about $180 if not.