Strange Sound

[Jim Shepard]

I've posted this on the truck side also, but I want to open it up to you car guys also. I just crawled under the truck, which is a B2B with 3-speed and fluid drive. I do not see any obvious issues with the u-joints. They're all dry and tight. The drive line doesn't have any play in it, in terms of side to side or up and down pressure; however, when I turn it, there seems to be some 'slop' in the differential. By that I mean when I turn the drive line by hand it moves about one-half inch before it engages and the axles turn. Also, if I grab the drive line and turn it vigorously alternating in both directions, I get the same noise I'm hearing when I drive it. It sounds like the gears in the differential are clanging together. I've never turned the drive line by hand before so I don't know if this is a new condition or if it's always been like that. It does seem to duplicate the sound I'm hearing. Whadda you guys think?

[Young Ed]

Jim I think I would drop the back 1/2 of the driveshaft and try turning just the diff. You may have too much freeplay in the ring and pinion.

[Jim Shepard]

You mean disconnect the drive shaft at the differential? If so, how does that help pinpoint the problem? Also, what causes too much freeplay in the ring and pinion?

[Young Ed]

After its disconnected you can turn just the rearend by hand and see if it still makes the noise. Freeplay is how much the pinion will turn before turning the ring gear. You should be able to feel it when switching directions. What kind of noise are you hearing?

[Reg Evans]

Jim, Have you lubed the U joints and topped off the tranny and rear end?

[Jim Shepard]

I haven't lubed anything yet. I guess that would be a first thing to try and see if it changes anything before I start tearing into it. What goes in the tranny? All I've ever seen is auto trans fluid.

[Reg Evans]

Same stuff that goes in the rear end. 90 weight. Also pull the drive shaft off and take the round sheet metal cover off of each end and put some grease in each one. Mark the front of the drive shaft so you don't reverse it. I wouldn't fool with the fluid coupling until I had tried those areas first.

[Niel Hoback]

Jim, make some alignment marks on each u-joint housing and on the trans and rear end flanges so you can get the shaft back on the way it was. Chalk ,or a file mark, center punch mark, anything will do.

[Guest 57plymouth]

If you have 1/2" of free play, you either have a problem in the differential or a bad universal joint. Greasing it won't fix the problem. If the Universal is bad, it's bad and you have to replace it. The good news is that replacing a universal isn't tough and you get to bash stuff with a hammer!

[Jim Shepard]

Thanks, Reg. That seems to be it. Lubed the drive line and topped off both the tranny and diff. Both were way down. I used almost a whole gal. on both In fact, the diff never did fill to the hole before I ran out of gear oil. Bought some more today and I'll top off the diff in the next day or two. In the mean time, I took it out for a 20 mile run and it didn't make any noise and shifted much smoother.

[Reg Evans]

That's good news Jim. Keep an eye on your rear brakes now that the diff is full. Might need new seals.

[Jim Shepard]

Thanks.

[blueskies]

:D found this looking through my old files trying to find something else, and thought it funny for this thread...

[Plymouthy Adams]

I can just imagine the voice of zsa zsa now...but darlin'.....gag me with a stick

[Normspeed]

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