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Discussion Starter · #1 ·
I have new universals on the 66 Mustang and a rebuilt differential. My C4 could be the culprit. But what could cause a bit of sloppy behavior or free play. Is there a section on a c4 that wears to the point it is loose. It has been rebuilt by a reputable shop. My rpm is 800 and the cam is a 270hr Comp unit ...Might be the idle is a tad high



Greg
 

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Is there play in the rear end itself? Sloppy linkage? That wouldn't make any noise though but slack in the rear end will make noise when you put it in gear if you can turn the drive shaft a little ways before it stops. Unless the rear has been reworked too then that probably isn't it.
 

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X2 on it being the rear end.... To much back lash. (ie worn out gear set)

A way to test to see where the slop is coming from:
1. Leave car in park, crawl under car try turning the drive shaft by hand, If in park you have slop, its the slip yoke going into the trans
2. Block wheels/tires so car cant roll, pull car into any gear or neutral and do same test, if you get rotation or slop then its in the rear end as I stated above.

The correct fix is a ring and pinion gear replacement..

HTH,



MRO.....
 

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X2 on it being the rear end.... To much back lash. (ie worn out gear set)

A way to test to see where the slop is coming from:
1. Leave car in park, crawl under car try turning the drive shaft by hand, If in park you have slop, its the slip yoke going into the trans


HTH,



MRO.....
also push driveshaft/slipyoke up down side to side..
Maybe tailshaft bushing. ??????
 

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Discussion Starter · #6 ·
Differential tight and just rebuilt...I was thinking he transmission on the c4 that has low miles maybe needs work ...It may need a bushing in the tail shaft as mentioned Not sure, but did find the shaft a bit off center when I placed the drive shaft on. I am not sure that the workings of the c4.

Greg
 

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The only time I've ever heard C-4 go CLUNK was when the bushing was bad and the drop in gear rpm was about 1700....

Rear ends and their play make a noise.

I say Jack and support. Put in Neutral. Move driveline to and fro. Then repeat at the rear wheels with one wheel blocked. Seek your clearance issue there. Just cause someone rebuilt the pumpkin, don't mean he did it right.
 

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Discussion Starter · #8 ·
Time to get under the car again. Thanks FE, the thought of removing the tranny or differential is not sitting well after I just put the automatic back in. Will investigate.

Thanks
Greg
 

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Discussion Starter · #10 ·
All the bolts on the transmission are tightened down. While idling the car placed it back and forth from park to drive. The noise is present and I had gone under it to check the slack in the amount the drive shaft moves freely. Not sure what would be considered acceptable movement. Test drive today with some temporary insurance :D End of Feb, and it looks like a great day here.



Thanks a bunch
Greg
 

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All the bolts on the transmission are tightened down. While idling the car placed it back and forth from park to drive. The noise is present and I had gone under it to check the slack in the amount the drive shaft moves freely. Not sure what would be considered acceptable movement. Test drive today with some temporary insurance :D End of Feb, and it looks like a great day here.



Thanks a bunch
Greg
end of Feb. there , its 2 days past mid Feb. here and the weather sucks
 

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Maybe you just forgot bolts in transmission mount or something like that

X2, I had a CLUNK in a Taurus when put into gear and it was a loose or busted motor mount. That was a happy day!
 

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Discussion Starter · #13 ·
lol....Ya might have jumped the calender up a bit to the end of Feb :) I need some sunshine to get things moving. Turned the idle down a touch and some fine tuning ...The differential may have a bit of play but not something really bad..I would say it is acceptable for now. In a c-4 not sure if there is free play in that tranny when it is in neutral. I am gong to dive into the universals to see what if any wear. Maybe all the grease I pumped into them is just hiding an issue



Greg
 
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