What is this noise?

[Old Henry]

Take it to Chucks up the street and work on it there.

Funny you should suggest that. It's exactly what Chuck suggested and I agreed to until today when I figured out how to roll Old Henry out of G'Raj Mahal onto the driveway for our family gathering on Dec. 10th if he hasn't got his back wheels back on yet - just lift his back end up with the floor jack and wheel him out. Just did it and it worked fine. (Didn't roll quite as easy as on his wheels but I still got him out on my own - first I took some time to grease all the wheels on the floor jack to make it roll as easily as possible.)

 

[Old Henry]

VILLAIN APPREHENDED!!

Who wudda thunk it?? Here's the cause and source of the noise.

It was that danged coupler pin I've mentioned before that made such an annoying noise for over a year before it finally wore down enough to fall out. I thought I was done with it and it was just sitting in the bottom of the torque tube, which it was, until halfway between Arco and Blackfoot Idaho two weeks ago when it found its way to where the tabs of the lock washer between the two pinion nuts protruded - then got caught by them (that was the first big bang and probably the second one too) and jammed there to catch and knock whenever there was no load on the drive line. My theory on that is that when the pinion gear was under load it was pulling down on the front of the ring gear which may have lifted it up just enough to clear the pin remnants. Then, when there was back pressure on the drive line (decelerating) I could hear the noise but when there was no load either way the pinion gear could just drop down ever so little but enough to hit the fragments of the pin and cause the noise.

I am mighty relieved that I didn't have to open up the banjo and do anything in there. All that I've read about that convinced me that I didn't have the specialized tools necessary to do anything in there and would have to just try to find a used banjo already set up if anything had to be done. What a relief I don't have to deal with that.

Here are pictures of the culprits.

This one shows the three pieces of the pin that was out and laying in the bottom of the torque tube next to the pinion nuts and the one remaining head of the other pin that was still in there but the head was rubbing on the inside of the torque tube. (I could hear that with the stethoscope.)

This is just a little closer showing the pin that was still in there with the head rubbing on the inside of the torque tube and the damage to the lock washer.

So, question is: whether I should even bother to put pins back in or whether they are so un-needed and useless compared to the trouble they cause that I can just leave them out and not have to worry about this problem any more.

What do you think?

Oh yeah - what about all of the metal in the differential oil? That all came off of those lock washer tabs and pin fragments and flowed back into the differential through the drain hole at the bottom of the banjo housing.

 

[Planojc]

Pin it for sure.

 

[G.M.]

Is that pin hollow? All the pins Ihave seen or used were solid. I use a solid pin and heat the ends peening them like a rivet and never had a problem. Make sure there is no wear or play in the coupling, that will shear the pin. G.M.

 

[don-wi]

If it were my car I'd be opening it up. I'd want to really take a good look at the pinion bearings and carrier bearings. It doesn't take much metal to score a bearing. By taking it apart you can get it cleaned up inside also, I don't think flushing it out would remove all the metal.
Good Luck
Don

 

[JM 35 Sedan]

If it were my car I'd be opening it up. I'd want to really take a good look at the pinion bearings and carrier bearings. It doesn't take much metal to score a bearing. By taking it apart you can get it cleaned up inside also, I don't think flushing it out would remove all the metal.
Good Luck
Don

I agree with Don. Do the job right the first time so hopefully you don't have to do it again later. I would also want to check the condition of the splines on the drive shaft, the pinion and the coupler. There must be slop in the fit of the splines to cause them to shear pins. As GM said, those pins do not look like the correct parts for the job. The correct type pins should be put back in as he described. I would personally take this opportunity to check the complete rear for everything including gear alignment, bearings, seals, etc., etc. There are some good procedures posted on the internet on how to do everything necessary. If you don't feel confident doing it yourself...find someone who can. JMO.

 

[Henry/Kokomo]

Considering that Old Henry doesn't just drive around the neighborhood, I'd be really tempted to do a complete job. The metal particles can really cause some mischief. Renewing the pins with proper ones seems necessary, too. FWIW

 

[41ford1]

I agree with the others. Go through the rear end. You saw evidence of metal chips in the drained oil. Not a good sign.

 

[Old Henry]

Pin it for sure.

Is that pin hollow? All the pins Ihave seen or used were solid. I use a solid pin and heat the ends peening them like a rivet and never had a problem. Make sure there is no wear or play in the coupling, that will shear the pin. G.M.

Although the pins do look hollow because of the way thay are worn they are the stock solid pins that were peened on as described (by someone else in my abscence). All indications are that they are the correct solid pins installed correctly. I know there was some wear of the splines on the drive shaft and pinion shaft when the driveline was "rebuilt" 25,000 miles ago. A new coupler was installed. As has been suggested, the only reason I can think of that these pins failed is too much play in the spline fits. That being the case, and nothing more I'm going to do about it, I am still inclined to leave the pins out unless someone can give me a real good reason to put them back in other than "tradition". Anyone?

 

[Mart]

I can see what you are thinking, but I think one of the functions of the pins is to stop the driveshaft drifting forward. Thinking further, they do nothing in the driving direction, the splines take care of that, so fore and aft location is their only purpose.

I did read a post where someone described some pins that were turned undersize, but can't remember the exact reasoning behind it.

I once used a high tensile allen headed bolt instead of a pin and that broke. I think the pins are better if they are quite soft and malleable.

Is there clearance for a hose clip? if you put new pins in, and a hose clip over each one with the heads 180 degrees apart, if a pin broke, the clip would hold the remnants in place and stop any repeat of the noise.

On the other hand, maybe having the noise is a good warning that the pins have broke.

Mart.

 

[41ford1]

I can see what you are thinking, but I think one of the functions of the pins is to stop the driveshaft drifting forward. Thinking further, they do nothing in the driving direction, the splines take care of that, so fore and aft location is their only purpose.

I did read a post where someone described some pins that were turned undersize, but can't remember the exact reasoning behind it.

I once used a high tensile allen headed bolt instead of a pin and that broke. I think the pins are better if they are quite soft and malleable.

Is there clearance for a hose clip? if you put new pins in, and a hose clip over each one with the heads 180 degrees apart, if a pin broke, the clip would hold the remnants in place and stop any repeat of the noise.

On the other hand, maybe having the noise is a good warning that the pins have broke.

Mart.

I think Mart is right on. The idea of turning down the pin would compensate for worn splines. That way the splines take all the rotational force and not the pin since it would float in the hole.

 

[Old Henry]

I think one of the functions of the pins is to stop the driveshaft drifting forward. Mart.

So, where would the drive shaft drift if it drifted forward? All I can think of is the U-joint? Is there anything that would be affected negatively by a little forward and back sliding? I'm not coming up with anything. When the drive line was disassembled to rebuild it 25,000 miles ago the pins were long gone and had been for I don't know how many years without any affect as far as I could tell. It was the guy that rebuilt it that decided to put them back in, much to my shagrin now that I've suffered from it. The only possible downside to leaving the pins out that I can think of is some wear of the splines from the friction of sliding slightly forward and backward. That doesn't seem very likely since that coupler section is lubricated by the differential oil. Still thinking about it as you can tell. So far I've only had the downside of the pins and am struggling to come up with an up side.

 

[Old Henry]

Is there clearance for a hose clip? if you put new pins in, and a hose clip over each one with the heads 180 degrees apart, if a pin broke, the clip would hold the remnants in place and stop any repeat of the noise.
Mart.

There is hardly enough room in there for the heads of peened pins, much less anything like a hose clip.

 

[Old Henry]

. . . maybe having the noise is a good warning that the pins have broke. Mart.

Knowing the pins have broken is only good to know if having them not broken is a good thing. So far, it's looking like having no pins to break and make any noise is better than whatever good the pins are. I'm still thinking about it.

 

[G.M.]

Fixed right it will last for hundreds of thousands of miles. The last fix only lasted 25,000 miles. G.M.

 

[Old Henry]

I think Mart is right on. The idea of turning down the pin would compensate for worn splines. That way the splines take all the rotational force and not the pin since it would float in the hole.

I don't know how you'd peen undersized pins without swelling their diameter up to fill the holes.

 

[Old Henry]

Fixed right it will last for hundreds of thousands of miles. The last fix only lasted 25,000 miles. G.M.

I'm not seeing where my last fix was not fixed right. It seems like it was done exactly the same way you suggested. What are you talking about? Can you be more specific about how you did it differently than he did it?

 

[41ford1]

If the undercut is the same length as the inner shaft the ends can be peened against the collar. The under cut would prevent the pin from taking the rotational force caused be the worn splines. I guess the real question is: Where they ever installed when the car was built? When the rear was done 25,000 miles ago, was that the first time it was opened up?

 

[Old Henry]

. . . the real question is: Where they ever installed when the car was built? When the rear was done 25,000 miles ago, was that the first time it was opened up?

When the torque tube was removed from the differential there was a remnant of a bolt with threads on it in that end of the torque tube that had apparently been used for the pin at some point and come out. I have no reason to believe that pins were not installed when the car was built. I know my brother broke a couple of rear axles hot rodding the old car after I left home in the early 70's and replaced them. He probably opened that up and may have stuck the bolt in.

 

[ford38v8]

Henry, check your drive line front to back. New motor and ****** mounts snugged down, anti-chatter rods properly installed, correct shackles and spring U bolts cinched up properly. Now check that you have the thrust washer installed at the U joint. All that's left is the coupler, the worn splines, and the pins. Buy a new coupler and new pins. Pick up a drive shaft with better splines, and seriously consider changing out your ring/pinion, or otherwise, cross your fingers.