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According to the parts eper cd, for the 94's and continuing on for the 95's there were many changes to the gearbox and diff housing as well as the internal parts in order to stiffen/strengthen the drivetrain. I was able to follow the changes through the eper effectivities, but have lost my notes. The effectivities usually said only that "part was modified for increased stiffness".

They evidently knew there were potential problems.

I suspect the casings can be changed, but don't know for sure. You would have to be sure the "ring and pinion" gears match as well.
 

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here is the fix chrysler came up with, part 4800059. I don't think this will fit the alfa but maybe there are similar chrysler parts. One would have to use longer bolts and put a nut on the end of 4 bolds.

Comments? How do you think this would affect the balance?
Rgds,
David
 

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Why is this not a problem with conventional rear ends and it is a problem with the diff in the front wheel drive cars? What is different? Is it that the conventional rear end axles are splined and held in place by the rear wheel bearings, and that the FWD axles are held in by this pin? I'm trying to get straight what the mechanical problem is.
 

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That would suggest to me that their problem, was the pin migrated out. Seems to me a few little tack welds even at one end of the pin would do the same thing.
Charles
 

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That would suggest to me that their problem, was the pin migrated out. Seems to me a few little tack welds even at one end of the pin would do the same thing.
Charles
Don't think its the pin migrating. If you do a search on the dodge caravan transaxles, they talk about the pin disintegrating due to do much stress on the pin. The brackets are the fail safe should the pin break up. So I was told at the transmission shop. Tomorrow morning I'm going to a large transmission parts supply. They claim to have several sizes of those brackets.

As for welding, the transmission shop said the pins are spring steel and the heat from welding would weaken the roll pin. Just to be clear, are you talking about welding the roll pin or the pinion shaft?
 

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I'm thinking welding the big spider gear pin (pinion shaft as you say) (Cardisc calls it the "side pinion shaft") to the spider gear/ring gear housing (the pumpkin itself) (the darker circle part of this picture). Just a couple small tack welds. If the spider gear pin breaks, what good does the bracket they added, other than to retain the pin from coming free and busting the tranny case? It will still be broken and most people would probably keep driving with it busted (though it would probably be making gear noise), with still dire consequences given enough mileage, like now your spider gears disintegrate from mis-mesh and smash through the case anyway. I just don't see how it could help much other than to stop migration. But I'm no tranny expert by any means. EDIT: I just noticed on the Cardisc that it is showing the side pinion shaft is retained by a roll pin as you say, so it shouldn't be migrating at all unless that broke or backed out. I guess the side pinion shafts are simply breaking and then all heck breaks loose, in which case the bracket you are picturing or welding will only be a possible fix for the all heck breaking loose, but the diff will still need work. Drive you car nice since it's apparently a fatigue problem! ;) Replace it if you have it apart, I guess.
Charles
 

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Charles,
I'll pose the welding idea to the transmission parts supply shop tomorrow.

The chatter on the net about the chrysler transaxle was the pinion shaft migrating and destroying the transaxle case. If they could hold it in place, they could just have to replace the diff, not the whole case/transaxle I guess.
 

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Charles,
I'll pose the welding idea to the transmission parts supply shop tomorrow.

The chatter on the net about the chrysler transaxle was the pinion shaft migrating and destroying the transaxle case. If they could hold it in place, they could just have to replace the diff, not the whole case/transaxle I guess.
That Dodge caravan tranny failure happened to my bud's wife on I-81 in middle lane with her grandkids. Luckily no one was hurt but car was 6k out of it's 80k extended warranty and cost them about 3200 to get it fixed with new rebuild/modified/upgraded tranny as their core was not salvageable.
 

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Discussion Starter · #69 ·
Charles,
I'll pose the welding idea to the transmission parts supply shop tomorrow.
I talked to a trans shop yesterday as well as a couple of welding "experts." Where they obtained credentials I dont know. They said that it is very difficult to weld on cast metal properly (for me with a MIG welder - have to pay someone to TIG it properly otherwise they claim the welds will fall off. Who knows).

Also - it seems we are discussing two types of failure here. One is the pin actually breaking up and causing problems, and the other is the pin actually making its way out as a whole and tearing the casing up in the process (like mine).

For my case (no pun intended) it seems that the tack-weld or retaining method would have prevented failure (maybe until the pin actually broke).

As for the other failure discussed, the only solution would be to have a higher quality steel pin, yes?


Also - it would be extremely easy to fabricate a bracket like the one for the dodge caravan, especially with a spare broken/damaged diff to hammer over to form fit the steel.

On a final note - I NEED MY GEARBOX. everything is ready to go back in save the missing gearbox. When the time comes - how worried should I be about lining up the input shaft??? It seems like a very small target.
 

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But how do you really know if the pin migrated out as a whole? By the time I saw mine it was in pieces from striking the case. My point is, if it was migrating out as a whole, it means the roll pin (that retains it) broke. So let's say the roll pin did break and it migrated out to the case. The end result will appear the same, as one that broke and then came apart. It makes a difference only in what is the real cause of the problem, the strength of the diff pin or a problem of diff pin retension. I'm not sure any of us knows for sure?
Charles
 

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Discussion Starter · #71 ·
But how do you really know if the pin migrated out as a whole? By the time I saw mine it was in pieces from striking the case. My point is, if it was migrating out as a whole, it means the roll pin (that retains it) broke. So let's say the roll pin did break and it migrated out to the case. The end result will appear the same, as one that broke and then came apart. It makes a difference only in what is the real cause of the problem, the strength of the diff pin or a problem of diff pin retension. I'm not sure any of us knows for sure?
Charles
Charles - my diff pin is still in one piece, even after the destruction of that case. I'll get a picture when I find the camera.
 

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my diff pin is in one piece also, roll pin missing of course. Actually, the diff bin had only migrated about half way out. I've got to think the problem is the roll pin.

Here is a photo of a smaller diff pin bracket I picked up today. As you can see it almost fits. Its from a smaller Chrysler product, don't have a part number. I will have to source longer bolts and some nylock nuts.

Comments on this alternative?
 

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I will have to source longer bolts and some nylock nuts.

Comments on this alternative?
It looks viable to me, but what do I know? I _would_ suggest you keep things balanced by pairing any longer bolts and added nuts on one side of the axle with partners on the other side. Just my musings. maybe add a little of the wicking Loctite Green after installation as a bit of insurance?

Michael
 

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My diff pin was in pieces but interesting that yours was in one piece, yours surely sheared the roll pin. :eek: I hate to say it but, we may not have enough clearance in the tranny case for longer bolts/nuts and a diff pin retainer bracket, though it looks like a good solution especially if you put one on one side and another on the other side for balance and to keep it from going either way.
Charles
 

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Discussion Starter · #75 ·
my diff pin is in one piece also, roll pin missing of course. Actually, the diff bin had only migrated about half way out. I've got to think the problem is the roll pin.

Here is a photo of a smaller diff pin bracket I picked up today. As you can see it almost fits. Its from a smaller Chrysler product, don't have a part number. I will have to source longer bolts and some nylock nuts.

Comments on this alternative?
It's going to be tough to keep things balanced with the locknuts on the outside, not to mention keeping clearance.

Why not tackweld the bracket to the end of the bolt? It would be easy to weld on the bolt, and almost as easy to grind it off if you ever need to remove the bracket. MIG welding on that bolt would be very easy - and that way you can make your own bracket from thinner (lighter) steel if you wish.
I think I may take that route as well as putting a set screw in place of the roll pin.
 

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It's going to be tough to keep things balanced with the locknuts on the outside, not to mention keeping clearance.

Why not tackweld the bracket to the end of the bolt? It would be easy to weld on the bolt, and almost as easy to grind it off if you ever need to remove the bracket. MIG welding on that bolt would be very easy - and that way you can make your own bracket from thinner (lighter) steel if you wish.
I think I may take that route as well as putting a set screw in place of the roll pin.
I like the tackweld idea. These brackets are pretty light as it its. I wasn't looking forward to adding longer bolts and nuts.
 

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Discussion Starter · #77 ·
I like the tackweld idea. These brackets are pretty light as it its. I wasn't looking forward to adding longer bolts and nuts.
Here's another alternative: those big diff bolts would be able to handle a tap and thread, and you would be able to add a machine screw with a washer to hold the bracket (for those who aren't welding inclined). I guess you could even tap into the diff carrier, although I wouldn't like drilling on that thing...

So many options!

Let's have some volunteers step up...

Each volunteer tries a different variation, then an all-out race would be held to see who breaks first!!
Ready........GO!
 

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Guess we could use a part number for that last little bracket. Will it be possible to get that? Welding that thing onto the ends of the bolts seems the best solution yet from a clearance standpoint and straight forward to do and pretty easy to undo with a grinder.
Charles
 

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Personally, I wouldn't weld anything onto a heat treated high alloy shaft like that. It takes pretty high loads, and I wouldn't want to compromise the strength or fatigue life. and I sure wouldn't drill or tap any more holes into the diff cage. That would just shorten the fatigue life of that highly loaded piece.

I think the problem is how to better ensure the roll pin stays in the cage, although the Chrysler style retaining brackets show promise. I think the shaft working back and forth as the diff works can slowly work the pin out of it's hole in the cage, thus releasing the shaft.
 

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Looks like "we" are back to looking at an internal circlip groove on the pin bore. That seems subject to none of the above problems. "To a man with a hammer, everything looks like a nail." (And I do NOT have a circlip groove cutter.)
 
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