Axle Shaft Replacement

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Joined
Apr 17, 2013
Messages
460
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Location
Virginia
My Car
1971 Mach 1
So I got my new third member in and that fixed some of my issues. Including the annoying noise the car made when slowing down in gear. But it didn't fix my clunk. Unfortunately that is axle play from a worn shaft. 42 year old car with 94k miles whoda thought.

So I have been searching for three days now. Moser makes replacement 31 spline axle shafts for 71-73. But I can not for the life of me find stock replacement axles. Seems nobody is producing these damn things. Which sucks because the Mosers are $400 not including supporting parts.

On another note I rather like the new 3.70 gears and Detroit Locker. Yes the clicking is noticeable in tight corners. But it really isn't that loud. Makes for a real nice take off. Drivability is good. I can understand where it could cause an issue in wet weather but. But hell the car acted badly in wet weather with the trac lok. So I like the idea that I will never have to replace clutches ever again.

 
So I got my new third member in and that fixed some of my issues. Including the annoying noise the car made when slowing down in gear. But it didn't fix my clunk. Unfortunately that is axle play from a worn shaft. 42 year old car with 94k miles whoda thought.

So I have been searching for three days now. Moser makes replacement 31 spline axle shafts for 71-73. But I can not for the life of me find stock replacement axles. Seems nobody is producing these damn things. Which sucks because the Mosers are $400 not including supporting parts.

On another note I rather like the new 3.70 gears and Detroit Locker. Yes the clicking is noticeable in tight corners. But it really isn't that loud. Makes for a real nice take off. Drivability is good. I can understand where it could cause an issue in wet weather but. But hell the car acted badly in wet weather with the trac lok. So I like the idea that I will never have to replace clutches ever again.
Call these guys..

http://www.yukongear.com/DiffDetails.aspx?DiffID=168&PartsLink=PartsList.aspx%3fSearchMode%3dCat%26CatID%3d22%26CatName%3dAxle%2b-%2bRear%2bLeft%26MakeID%3d2%26MakeName%3dFord%26ModelID%3d275%26ModelName%3dMustang%26Side%3dRear%26DriveType%3dRWD%26DiffID%3d168%26DiffName%3dFord%2b9%2522%2b%289%2binch%29%2b-%2b28%2bSpline

 
Yall are misunderstanding. I found the Moser Axles and they are $400. I am looking for stock replacement. Those are not stock replacement. They are an upgrade to the stock axles. Generally speaking stock replacements are alot cheaper.

I don't see a need to upgrade the axles if I don't have to. Stock 31 Spline axles as far as I know are plenty strong.

Looks like I might not have a choice though.

 
Yall are misunderstanding. I found the Moser Axles and they are $400. I am looking for stock replacement. Those are not stock replacement. They are an upgrade to the stock axles. Generally speaking stock replacements are alot cheaper.

I don't see a need to upgrade the axles if I don't have to. Stock 31 Spline axles as far as I know are plenty strong.

Looks like I might not have a choice though.
Contact Don of OMS. That is where I got my axle.

mike

 
So I got my new third member in and that fixed some of my issues. Including the annoying noise the car made when slowing down in gear. But it didn't fix my clunk. Unfortunately that is axle play from a worn shaft. 42 year old car with 94k miles whoda thought.

So I have been searching for three days now. Moser makes replacement 31 spline axle shafts for 71-73. But I can not for the life of me find stock replacement axles. Seems nobody is producing these damn things. Which sucks because the Mosers are $400 not including supporting parts.

On another note I rather like the new 3.70 gears and Detroit Locker. Yes the clicking is noticeable in tight corners. But it really isn't that loud. Makes for a real nice take off. Drivability is good. I can understand where it could cause an issue in wet weather but. But hell the car acted badly in wet weather with the trac lok. So I like the idea that I will never have to replace clutches ever again.
Are you absolutely certain it is the axle(s) causing the clunk? I have never heard of an axle causing a noise like that (but I am not saying it isn't possible).

Have you checked the u-joints carefully? A bad trans mount or motor mounts could cause noise as well. Even a sticky governor inside the transmission can cause a clunk noise with delayed shifts when slowing down or taking off.

Just some thoughts.

 
Quite sure. The DS Axle is nice and snug no play in it at all. The PS can turn a noticeable amount with the drive shaft not moving. The clunk occurs when taking off but primarily when going from reverse to forward and vice versa.

I'll get with Don because so far everything is 350-400 for axles which I don't really want to pay that much.

 
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Are you absolutely certain it is the axle(s) causing the clunk? I have never heard of an axle causing a noise like that (but I am not saying it isn't possible).
They "clunk". Especially if the bearings are worn, have locked up,

and caused wear on the axle. In the picture the bearing has worn

solid so all the friction is on the axle.

mike

P4200316.JPG

 
Axles do not make that kind of noise. They whine if the bearing is bad or they make one loud singular bang when they break.

I can not even figure out how to sabotage an axle to make the noise you

discribe.

If you pull them out and the splines are not buggered up and the where the bearing fits on the shaft is OK then you they are good. Press on a new bearing and reuse them.

What you are discribing is to much play. It is in the rear itself or more likely in the u-joints or trans.

One fun thing to do is paint a stripe down a new axle and then race it for a season. Pull it out after a few hundered passes and the paint line will no longer be straight. The shaft itself will also be a few thousanths shorter.

I had one in the corner of my shop that looked like a barber poll. It was also in 2 pieces (refer to above paragraph one).

Keep us posted with what you find.

Paul



Are you absolutely certain it is the axle(s) causing the clunk? I have never heard of an axle causing a noise like that (but I am not saying it isn't possible).
They "clunk". Especially if the bearings are worn, have locked up,

and caused wear on the axle. In the picture the bearing has worn

solid so all the friction is on the axle.

mike
Mike,

We posted at the same time. A locked bearing would make a continuous growling nasty horid sound that gets worse as you speed up. It would also most likely leave him on the side of the road because it would get hot enough to set the gear fluid smoking.

If this is his problem then he needs more that an axle shaft. He will need a whole rear end housing due to the damage caused by the bearing spinning in the tube.

I assume he has pulled the axle and would have noticed this.

It will be interesting to see what he finds.

Paul

 
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Let me explain this slowly because it is obvious some are not getting it.

A hema ha hema hema ha..............:D

This is simple. Its the PS axle. Splines are worn somehow. On a visual inspection they look fine. But I don't have much to base a visual inspection off when talking about wear. Easy to tell buggered splines on an axle. But long term wear is a different story especially since the car has only been driven 1k miles in 10 years. The axles were in it a long time before I got the car. I don't know the history on the Boss 351 the 9" came out of. But a guess would say the car was dogged out before it was crashed. How do I know its the axle?

1) The clunk is coming from the rear of the vehicle. Easily noticeable and it happens primarily when going reverse to first and opposite.

2) The third member is a fresh rebuild. Not only that but the same issue occurs with 2 other third members.

3) Immobolizing the drive shaft the DS Axle is snug does not turn. The passenger side axle with wheel turns maybe 10 degrees if I had to guess.

End of the day the one axle has an issue. If I get a chance this weekend I will get the car on stands and post a video of exactly what I am talking about.

The clunk seems to be caused by the play as the third member engages the worn axle. From what I can tell.

 
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Splines either engage or they don't. If they start jumping teeth then the axle is toast and the pumkin is trashed and filled with metal shavings.

You are discribing significant play - worn splines may allow a few hundrend thousands of movement and would not created noticible movement on the driveshaft visible with the naked eye.

10 degrees is a huge amount of movement. The whole axle would have to be jumping 3 or 4 axle splines for this amount of movement.

I do not have any big spline axles that are not in a car right now or I would loan you one.

You can test this with your current axle. The axles pass through and stick out past the case gears quite a bit. Put some washers behind the axle flange to pull it out a bit. This will move the splines out of the rear end just a bit and should engage some "fresher" un worn splines then check for your driveline slop. (do not drive it this way).

I agree with the above post - who ever rebuilt your rearend may have left the side gears with to much play.

Like I said before I could not sabatage an axle to do what is happening in your car but I could certianly set up a rear carrier so one side is tight and the other is loose.

Come to think of it I have done that before - that is why I farm out most of my differential work.

- Paul

 
Like I said it is a noticeable amount of rotation. But its not the Carrier. Highly unlikely that three different carriers have the same exact problem with the same axle. The only common denominator is the PS axle. Why its like that I don't know. Also the side gears are gone since a Detroit Locker is installed now. Unless I am misunderstanding the gears you are talking about.

In all my years I have never run across an issue like this. Multiple destroyed axles for various reasons. But never a setup with this much rotational play in the axle.

Luckily it isn't jumping splines yet. But I think that is not far off. Like I said I will see if I can grab some video this weekend. Not driving the car right now for that very reason.

I agree I hate differential work also. Farm all mine out to other people also. But in this case its not the diff.

Looks like I most likely will be getting these since they are bolt in ready and the best priced set I can find.

http://www.ebay.com/itm/181217914469?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 
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zlt6o8.jpg


The items marked left and right axle gears is what we are talking about.

These are inside the "Detroit Locker" also called the carrier. If they are not set up right or there are broken/worn parts you will get the exact situation that you are discribing.

Many people rebuild a rear but never open up the used locking carrier they bought to see what is wore out or broken inside.

All Boss 351's came with a traction lock differentials with 3.91 gears and not detroit lockers. People interchange the names but they are actually different carriers and work differently.

A true Detriot Locker was very rare in a Ford. Some 428 Cobra Jets and a very few 429 71 Mustangs and Cougars had Detriot Lockers.

A Detriot Locker has no clutches and makes a loud pop when the spider gears mesh and unmesh.

A Traction Loc has clutches and does not make the popping sound.

A DL has significant freeplay at the driveshaft - almost a 1/4 turn. They also "feel" clunky when turned by hand.

A TL should have little or no free play at the driveshaft and feel smooth when turned by hand.

If yours is out of a Boss 351 then it is a TL, If it is a true DL then sell it and buy a TL because you will not like how it sounds and operates in a street driven car.

Keep us posted.

Paul

 
I understand your trying to help but your way off the topic trying to tell me what I have in my car. This isn't my first rodeo. So I'll explain it. I already did the troubleshooting and am pretty positive I found the fault. Now the problem surprised me because it is odd. But not totally unheard of just rare. I have three difs.

3.50 Trac loc

3.91 Trac loc originally in the axle from a crashed boss

3.70 Detroit locker currently installed

Now for everone who says Detroit lockers make a loud snapping noise ya might want to check out the new ones. They are a lot more civilized these days and click now in turns. The noise can still be annoying if that sort of thing bothers you. Road manners aren't bad on dry pavement but can be bad on wet. But that depends on driving style in my experience. But nothing like they used to be. The design has improved a lot.

But thanks again and I will update the thread with video this weekend. Including some of the Detroit locker so people actually know what it sounds like.

 
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I understand your trying to help but your way off the topic trying to tell me what I have in my car. This isn't my first rodeo. So I'll explain it. I already did the troubleshooting and am pretty positive I found the fault. Now the problem surprised me because it is odd. But not totally unheard of just rare. I have three difs.

3.50 Trac loc

3.91 Trac loc originally in the axle from a crashed boss

3.70 Detroit locker currently installed

Now for everone who says Detroit lockers make a loud snapping noise ya might want to check out the new ones. They are a lot more civilized these days and click now in turns. The noise can still be annoying if that sort of thing bothers you. Road manners aren't bad on dry pavement but can be bad on wet. But that depends on driving style in my experience. But nothing like they used to be. The design has improved a lot.

But thanks again and I will update the thread with video this weekend. Including some of the Detroit locker so people actually know what it sounds like.
My mistake - I misread and thought that you are currently using a rear end out of a Boss 351 and as such would have a TL not a DL.

Old DL's have bad manors and a lot of slop. I have several old style DL's on the shelf as well as rear spools and will not sell them except for race only applications. I do not want to be responsible for wrecking someones street car because it sprinkled and the streets got damp.

How about this:

Are you sure it is not a case that the other side is too tight? Old DL's have nearly a quarter turn of free play - I am guessing that new ones will still have considerable play in them. They would have to have some due to the basic design of a DL.

I have been into dozens of DL's from the late 60's - never been into a new one because I got old and don't race anymore. It looks to me like they now have a sprag instead of spider grears but its still the same basic idea. If one of the wave springs is broken then that sprag will not retract all the way making that side tight. If it did not retract at all then it would act like a spool.

The reason I questioning your conclusion is that an axle is a solid chunk of steel. If it is not jumping splines then where is the considerable movement in the driveshaft coming from?

I like puzzels and doing post mortems on blown up race stuff to figure out what led to the carnage.

I am just about to slide out one of my axles and loan it to you to get this mystery solved.

I will now research the new style Detriot Lockers - Fun!

- Paul

 
I agree this one had me bamboozled for a while. At first I thought the same thing with the spider gears. Checked all the normal stuff U-Joints and worked my way back. Thats the reason I now have the rebuilt 3.70 DL center section installed. That fixed one issue. Because the rear end was making noise when slowing down in gear. But after trying a different center the problem is still present. It is a rather pronounced clunk to. I have never seen an axle issue like this before. After some research in google I found some threads on it. But not alot. I'll get some video up though. That should be a bit more easily understood.

The problem is I don't know the history of the Boss 351 the parts came out of other than it was crashed scrap. The axle, tranny, ram air and other parts were installed years before I got the car and the clunk has been around as long as I have owned the car. Just not as pronounced. Due to deployments and many other things the car wasn't driven hardly at all. This summer I finally have had the time to really dive in and start repairing many of the long term issues the car has.

 
The problem is I don't know the history of the Boss 351 the parts came out of other than it was crashed scrap. The axle, tranny, ram air and other parts were installed years before I got the car and the clunk has been around as long as I have owned the car. Just not as pronounced. Due to deployments and many other things the car wasn't driven hardly at all. This summer I finally have had the time to really dive in and start repairing many of the long term issues the car has.
Then the only constants are the axles, axle bearings, and the rear housing.

Check the housing for a cracked weld on the tubes.

I had a car that made a single but resounding clunk on hard exceleration and deceleration and after a great deal of pondering and parts replacing it was suggested that we check and reweld the axle tubes.

When we were grinding the factory welds down we found one side had a stress crack in it. Welded it up and no more noise. (free)

or

Find a local 4x4 / differential service - I bet they could inspect your axle and tell you if it is not right. (probably free?)

or

Replacing the axle bearings is cheap and simple enough. The worst that will happen is you end up with fresh bearings. (~100 bucks)

or

Buy new axles. ($$$)

- Paul

 
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