Got a loose diff. What do you think?

[375instroke]

Got a bad clunk going on and off the gas.  U-joints are good.  Tailshaft bushing could be better, but the real problem is that I can rotate one wheel about 30deg before the other wheel or driveshaft turns.  There isn't play in the driveshaft, so I think the play is in the spider and side gears.  Open diff, by the way.  I've got a 489 case 3.23 cone of unknown condition I could swap in.  I'm still amazed at how easy it is to accelerate this '69 R/T with an open 3.23.  I've owned other 440 cars before, and this one is no slouch on power.  My small block 3.23 Sure-Grip Darts spin the tires so easy, but they don't have any real power.

[375instroke]

How could it get this loose without making constant noise or exploding altogether?  Could long burnouts cause this by causing the spiders to burn up?

[Ghoste]

Long burnouts aren't going to cause your spider gears to "burn up".  As for your noise, my gut feeling is that you are looking in the wrong place.  Without being able to hear personally of course it makes it hard but I tend to think it's more a combination of factors or something a little different than what you suspect.  Noise questions are worse than what's it worth questions and I know this isn't much help.

[flyinlow]

30 deg seems like alot. But if you ad the slop in the spider gears + ring gear slop+ axle to sidegear slop + parking pawl slop on an open tall geared car you can turn a single wheel alot without anything being broken.

Did you look for loose rear axle u bolts ,trans mount or compainion flange bolts. 

[firefighter3931]

The 30* differential seems about right for an open centersection. My guess is that there is slop in the side gears, but probably not too much. Have you checked the fluid level lately ?


Ron

[375instroke]

There isn't noise.  You just feel a big clunk when getting on and off the gas.  The u-joints are good and look new.  There isn't rotational slop in the yoke.  Just the up and down slop of a loose tail shaft bushing, but I've seen worse.  The 30deg movement is before the other tire or pinion start moving.  I can't see how this can't be the cause of the clunk, but also don't see how something that I would think is very bad can't be progressing rapidly towards complete destruction.