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Rear end swap issues


Kiwicranbrook

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Hey guys, I am part way through swapping a Cherokee rear end into my 52 Cranbrook. Doing the diff swap was a piece of cake but I an having major issues with the driveshaft company. I have had the rear of the Cherokee shaft welded onto the Plymouth shaft and they don't seem to be able to balance it. They are blaming the front of the Plymouth shaft saying it's a CV coupling? Any one else had this issue? Any suggestions? 

 

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The Detroit joint used at both ends of the Plymouth shaft is not a CV joint despite its appearance from outside.

It is very likely that the driveshaft shop has the elements of the universal joints out of phase, that is , one is presently 90 degrees from where it should be.

In the early 60s Chrysler used a Detroit joint at the front and a Spicer at the rear so that is OK so far as it goes.  Also, and more seriously, what may be lacking in your installation is enough forward and back to allow for necessary variations in driveshaft length.  This will cause a very alarming noise on braking when the snout of the differential tends to nose down and will result in failure.

 Before you get in any deeper, have a splined slip yoke and spicer joint put up front and your troubles will be over. The Detroit joints can be expensive to service.

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The driveshaft hasn't been put in the car yet it's still in the shop trying to be balanced. They are suggesting putting a slip yoke up front but they are saying that it will be expensive to do. To the tune of around $500 just for the slip yoke

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4 hours ago, Adam H P15 D30 said:

Did you mix a Spicer type ujoint with the Detroit joint?  As I understand it, that's a no-no.

I believe later cars(like our 63 valiant) had exactly that. 

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Kiwi........when I used the 1962 Chrysler Royal shaft in the Dodge I just had the shaft shortened at the front where the slip yoke was and it worked fine........then when I installed the 1990 EA/EB Ford Falcon rear end I used the Falcon shaft and had the slip yoke from the Chrysler shaft spun off on a lathe and had it welded onto the shortened Falcon shaft, both times the shafts were in phase although only the first effort had the shaft balanced.....they were done 30yrs apart and by different places, however the unbalanced shaft was done by an engineering shop that does all the local speedway and hillclimb cars..........I'd be using a slip yoke but if mopar ones are hard to find what about those used by most 4wheel SUV's............btw the CORRECT way to shorten a shaft is to usually leave the REAR uni joint assembly on the original shaft then roughly cut the front of the driveshaft that fits the gearbox, then install this short shaft piece with the front uni joint and slip yoke or female spline end in a lathe and accurately cut thru the front shaft weld, you then have a accurately machine and square piece that is installed into the front of the old driveshaft and welded together and balanced if need be............if the old shaft is too short then its rear uni is also removed by a rough cut then spun on a lathe then BOTH front and rear joints are installed into a NEW LONGER piece of driveshaft tube and both welded & the shaft balanced..............depending on the difference in the two shafts diameter it may have been better to use one or the other shaft but it sounds like they have screwed it up.............is your Plymouth using a ball & trunion on the front?...........andyd       

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15 hours ago, Kiwicranbrook said:

The driveshaft hasn't been put in the car yet it's still in the shop trying to be balanced. They are suggesting putting a slip yoke up front but they are saying that it will be expensive to do. To the tune of around $500 just for the slip yoke

My local shop will make the whole shaft new for around $300. That is also what I paid for a new shaft with spicer u joints and a slip joint about 20 years ago in Austin texas. 

 

I'm guessing your biggest problem is you selected the wrong shop.

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sorry to hear that....when it comes to work like this, bringing the older stuff into the current century, one cannot help to think that the local car clubs and such would be a clearing house of 'who's who' in the local area for dependable quality work.  I have always suggested to check with the car clubs in your area, member or not, they will help guide you, often the local big box parts store has a line on who you can and cannot trust.  I do not recommend asking them aloud in a crowded store, remember, they still want to sell parts to the other guy also else they go hungry themselves....lol

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I'm closer but still a little bit far to walk...........I'd be trying some other places.............andyd

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