front output shaft excessive play

[Horst]

The gearbox is the only component not being original to my 151 but some takeout unit I had installed at some time (the original box was rusted beyond repair).

Now I have found today that the front output shaft has a significant wobble/play and I doubt the output seal can do its work any longer.

What part of the front output shaft set-up wear would cause this wobble. I have not pulled the output flange yet because I would need to drain the oil first, however I very much doubt that the splines are worn so much causing this play. Must be somewhere more down the transmission.

Anyone has a guess which part or combination of parts could be the culprit?

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[Hambone]

I would check the yoke first, I replaced one in the rear several years back that had a lot of wobble.

[Mr. Recovery]

Horst, here's a little better look at those parts. hope this helps.

I would think that a wobble/play would come from 1 of 3 places, item "B" flange/yoke, item "K" shaft, or item "M" bearing.

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[rickf]

You will have to split the case and replace #40 and all of the associated seals since that is the bearing for the front output. But, I tend to lean towards checking the yoke also because the front almost never has any real load on it. Unless the transmission had a lot of water in it or something else broke and the pieces damaged the bearing. I would drain the oil if you really suspect the bearing and look closely at the oil for metallic sheen.

[Horst]

Thanks so far, very helpful.

Could be the bearing but also could be the shaft 37 riding in the bushing 30.

In any case, if not the yoke, time to pull the pack. Nothing I had planned. Yikes.

[m3a1]

My experience with a wobbly yoke is that there is usually some external force that causes it to wallow out at the splines. In my case, it was because of axle shafts that went un-maintained. All the energy from axles that were incapable of changing length had to go somewhere and it ruined my yoke. Obviously axles don't factor into your particular troubles but yokes are yokes....are yokes.

So, if you have something wrong inside the pack, or a problem on the outside (with the driveshaft) the end result may be that the yoke took the punishment and may now be out of spec, along with whatever caused the trouble.

My guess is they chose the metallurgy of the yoke with that in mind so that it becomes an expendable part. When a yoke is out of spec, there is no economical way to fix it. Happily, yokes are rather inexpensive.

The point of all of this is, YES check the yoke but don't stop there. You should be looking for problems with more than one thing if a yoke is involved.

Cheers,
TJ

[rickf]

I have never seen a balance weight on a mutt driveshaft, It it is even the slightest out of balance spinning the speed it does with 4.88 gears that would take out a bearing. Or more likely a yoke as far out from the bearing as it is.

[Mark]

I had my driveshafts balanced on my jeeps, as the nuts on the u joints would come loose.I'll have to look to see how much weight.
I took these shafts to an alignment shop, they decided it was out of balance.

[Horst]

no progress so far as no time available. But I have ordered some parts respectively pulled some out of the parts stash to get prepared.

New seals with wear sleeves, new seals for no sleeves, new gaskets. Take-out but almost unused front drive, used yoke. Still hoping that Hambone is right and it is just the yoke and I don't have to pull the power pack however likelihood is low IMHO.

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[muttguru]

Horst,
just a thought on this. When I bought my A1 in 1980, I had a similar problem. Eventually I put the vehicle on stands and with 4WD engaged, I turned the front wheels and then the rear wheels. My brother held a steel ruler on the body underside and moved the end of the ruler towards the center of each propshaft. As I turned the wheel, the propshafts rotated but one touched the ruler's tip, then moved away slightly as the propshaft rotated. The propshaft was bent. i visited the US Army's RSA not far away and had a chat with a friendly mechanic. I asked him how it was possible that the shaft had a bend in it. His answer? It was probably picked up with a fork-lift truck at some time. He said that the lifting of M151 vehicles by forklift truck was forbidden, but it still happened occasionally. His cure? He "found" a new propshaft for me.

Ken

[rickf]

I have seen bent drive shafts on just about every vehicle I have gotten from the military from doing just that. My CUCV was bent so bad as soon as I tried to roll it on the trailer the shaft knocked one of the exhaust pipes off and then proceeded to break in half. That is just the facts of life with surplus. I don't know if Richie Bros. is still doing it now that they are running the auctions. considering what they are asking for starting bids I would hope not. I haven't bid on a vehicle since they took over. But Gov. Liquidation was quite well known for destroying things with forklifts. Anything they had to lift they destroyed, mostly by not lowering the forks and just stabbing right into the item. OOP's, oh well, it is just surplus. The same CUCV also had the passenger side door flattened by a forklift, probably the same one that got the drive shaft.

[Horst]

Turned out the problem is the shaft. Tried a couple of flanges on the shaft and they all had play. The bearing itself was good but the splines of the shaft are worn.

Good thing that there is no need to split the transfer and transmission to replace the shaft.

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[rickf]

That is from all that white knuckle driving through the Alps.

Actually it does not say much for the quality of the material when the shaft splines wear out before the yokes. They are supposed to be hardened shafts. You ought to try running a file over that worn shaft and see if it will cut anything off of it. If it does then the shaft was not hardened.

[Horst]

Transmission is from 13th Oct 1967. Probably has seen some miles in its life.

Nice work of the iPhone to remove all the clutter in the little garage

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[rickf]

You just did that so people like me could not look at all the goodies in the garage! I am quite sure your clutter has nothing on my clutter! I am actually working on that today. I need to get the Mustang in for some seeded suspension work and possibly a clutch and transmission swap.