Sounds like spinning of the "Wheel Of Fortune"

[EuroDat]

Are you drinking a Macdonalds coke in the rattle2 audio? ?? Sounds like it at 45, 101 and 110 seconds. Sounds a bit like uni-joints. They can be hard to check in the car. Generally when a uni-joint fails, the needles create vertical lines in the peg section of the spider. Mostly about a third of the peg on the driven side develops the vertical lines.

Acceleration and bumps change the geomentry of the rear axles and needles can click over the vertical lines.

[240Ziggy]

I put another diff with new gear oil 80W/90 is all i can find when i did it. Went to get 75W/90 semi-syntetic today at a subaru dealer. Got the car on jacks now looking for the culprit. Removed the tires and rear drums and ran the car on all gears. None that i can see but when i spin the rear axel the diff has some gear drag. Is this normal? Checking my other spares and hard to tell just turning by hand.

[240Ziggy]

4 minutes ago, EuroDat said:

Are you drinking a Macdonalds coke in the rattle2 audio? ?? Sounds like it at 45, 101 and 110 seconds. Sounds a bit like uni-joints. They can be hard to check in the car. Generally when a uni-joint fails, the needles create vertical lines in the peg section of the spider. Mostly about a third of the peg on the driven side develops the vertical lines.

Acceleration and bumps change the geomentry of the rear axles and needles can click over the vertical lines.

I used pry bars to check all of the u-joints and don't see any sort of play.

[EuroDat]

I have missed a bad uni-joint by checking for play with a really big screw driver. The play is minimal and depends on where the neddle contacts the spider when testing. The neddles could be on a ridge of the vertical lines. I think that is what happened to me when I missed the bad joint I had in an Escort. Finally changed it and click sound was gone. It was half full of vertical lines on two of the spiders pegs.

https://www.howacarworks.com/transmission/how-to-check-u-joints

Here are two screenshots of the spider pegs. Note on the second screenshot, the peg on the top side of the photo has the lines on the driven side and the bottom peg doesn't have them on the non driven side.

[EuroDat]

22 minutes ago, 240Ziggy said:

I put another diff with new gear oil 80W/90 is all i can find when i did it. Went to get 75W/90 semi-syntetic today at a subaru dealer. Got the car on jacks now looking for the culprit. Removed the tires and rear drums and ran the car on all gears. None that i can see but when i spin the rear axel the diff has some gear drag. Is this normal? Checking my other spares and hard to tell just turning by hand.

When you turn the diff by hand the other wheel often drags on the brakes etc and doesn't turn. What happens then is the internal spur gears in the diff rotate and the propshaft speeds up. That is what you are most likely feeling or maybe even hearing. They are designed for turning so the outer wheel can speed up and the inner wheel can slow down.

[240Ziggy]

Thanks EuroDat. I will double check the U-joints again. I hope i can narrow it down.

[240Ziggy]

On 6/28/2019 at 11:09 AM, EuroDat said:

Are you drinking a Macdonalds coke in the rattle2 audio? ?? Sounds like it at 45, 101 and 110 seconds.

Hey EuroDat, I didn't know what you meant at first and listen to it again. No, that wasn't me sipping cola and burping. ? It's the car from shifting gears.

Anyways, the ratlle noise has worsen plus it started to vibrate so what I did this weekend was changed one halfshaf with spares I have at a time test drove it.

The clunk is gone but it still vibrated after changing both haft shaft. I was going to change the driveshaft but the two spares I have were both short. Going to order the full u-joints and change all of them and see. Could a worned transmission and diff mount make the vibration as well?

 

[Mark Maras]

 The vibration is likely the drive shaft u-joints. The half shafts don't spin fast enough to set up a vibration. In my first Z, I had a nasty vibration at 80 mph and above.  Installing new u-joints in the half-shafts and the drive shaft did nothing to improve the buzz. I removed the driveshaft again and took it to our local driveshaft shop. The tube had a small dimple in it. (possibly from a floor jack?) I didn't notice it until they pointed it out. They re-tubed it and installed new Spicer u-joints. The buzz was gone.

[EuroDat]

10 hours ago, 240Ziggy said:

Hey EuroDat, I didn't know what you meant at first and listen to it again. No, that wasn't me sipping cola and burping. ? It's the car from shifting gears.

Anyways, the ratlle noise has worsen plus it started to vibrate so what I did this weekend was changed one halfshaf with spares I have at a time test drove it.

The clunk is gone but it still vibrated after changing both haft shaft. I was going to change the driveshaft but the two spares I have were both short. Going to order the full u-joints and change all of them and see. Could a worned transmission and diff mount make the vibration as well?

 

Driveshaft (Nissan call it a propeller shaft) are easy to get out of balance. Like Mark mentioned in his post, the haft shafts turn less than one third of the propeller shaft speed.

If you change the uni-joints, payparticular attention to the end play in the spiders. Check the FSM for the tolerance and order shims to adjust the end play.

It would be a good move to have the shaft balanced while it's out.

Rear transmission mounts and diff mounts can sag when they get old. Sagging can cause vibrations, especially if the bottom bolt hits the top section of the mount. The transmission or the diff can than tap on the bolt. You WILL hear and feel it.

Scroll down in the link and you will see what I mean.

http://www.atlanticz.ca/zclub/techtips/suspension/rearend/index.html