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nolant178

My 350 (probably) powered 260z!

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6 minutes ago, NewZed said:

The driveshaft could easily transmit motion to the diff, making the pinion gear bounce off of the ring gear.  The noise might be from the diff but the problem is probably in the trans or converter.  There's no way the car would move like it does if you had a tooth missing.  And at zero MPH the pinion gear would have to be slipping over the ring gear.  That would make a terrible grinding noise.

 

Put your camera under the car while you do the zero speed load test.  You'll probably see the propeller shaft bouncing back and forth a degree or two.

 

On the other hand, taking things apart is always a good learning experience.  You'll want to know your diff condition anyway.  The R180 really is small for a 350.

I wanted to make sure I understand: You're suspecting that an issue in my TC or my AT is transmitting excess motion to my diff, where the noise is manifesting?

 

I'm asking questions because I'm getting a lot of info from a very  helpful community and I want to make sure I'm understanding everything, not because I'm doubting anyone (in fact I'm extremely grateful to have people so willing to help diagnose!)

 

  1. So it was my understanding that the u joints exist so that the diff and trans can move independently of one another without causing issues - could this be a drive shaft u joint gone bad after-all? 
  2. And also, if there was an issue with the TC, wouldn't there be something noticeable while in neutral? Currently I can put the car in N and rev it to my heart's desire.
  3. My final question is in regards to the diff being small. I've read that its small for the 350, i've also read that auto trans are easier on diffs, also the r180 LSD seems to hold up fine in the STI, which seems to have comparable torque to many SBC 350's.

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Yes.  The R180's and R200's are notoriously loose and clunky diffs.  Lots of slop in the gears, and splines.  

 

In neutral there's no load.

 

Good luck.  You'll find it.

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My plan keeps shifting, as they do.

 

Tonight I'm gonna open up my diff and see what's going on in there. If its bad, I'm gonna start sourcing parts to do an r200. I realized that STI's can run the r180 because only 60-70% of the power is going to the rear at any given time...

 

I'll be sourcing parts now!

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Alrighty, making progress!

 

I cracked the diff open, and found some broken teeth! I may be the most excited person to ever find a busted diff on their car... but I think my issue is finally found. I'm currently trying to find everything to do the r200 swap, Ideally I'd go straight for an LSD, but may get an open diff to start out and swap to LSD later on for budget reasons.

 

You can see bits of broken teeth sitting in the bottom of the housing! And look at how dirty that fluid is. New diff time!

aqDpzLC.jpg

 

 

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Looks like your pinion haft was about to blow a hole in something.  It's trying to get out.  It happened to me long ago, on a GM diff.  Blew a hole in the diff cover.

 

Look at how the propeller shaft turns those gears and how they work.  Ponder how the gears could turn and slip on the broken teeth when the car is not moving.

 

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12 minutes ago, NewZed said:

Looks like your pinion haft was about to blow a hole in something.  It's trying to get out.  It happened to me long ago, on a GM diff.  Blew a hole in the diff cover.

 

Look at how the propeller shaft turns those gears and how they work.  Ponder how the gears could turn and slip on the broken teeth when the car is not moving.

 

 

I hadn't even noticed that... wow! Good eye! And I see what you're saying. I won't be able to test any further until the new diff is in, but this'll be a good time to inspect the trans and flex plate as well.

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As of about 15 minutes ago, I've ordered all of the parts I need including an r200 to install into my car! They should all arrive sometime during next week.

 

This weekend I'm going to drop my diff out of my car and take it apart to see how much damage I've done. I'll be attempting to sell anything that is usable.

 

After I take my diff out, I'm also going to replace the u-joints on my drive shaft, and inspect my Trans and Torque Converter for potential issues, since I'll have relatively easy access to them! I'll try to take pictures as I go.

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I've successfully installed the r200 in my Z! This is the most involved project i've done to date, and it went pretty well! I had a few hang-ups here and there, but overall the installation went very smoothly.

 

Much to my delight, and expectation - the knocking noise is gone! I was finally able to put some time behind the wheel to see what other issues I'm dealing with.

 

I also attempted to fix the speedo reading. I swapped to a 24 tooth speedo driven gear. My readings are closer now, but still need to be adjusted, I may just get a GPS speedo and be done with it.

 

My first weekend of cruising in the car has been great! So many people love the car, they are asking questions about it, taking pictures and videos. I knew it wasn't a super common car in the Chicago area, but damn people really love it! I'm excited to finally be on the road (for now haha...)

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