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Muzez

What To Look For in Used Differentials (R200)

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Hi Guys, 

Going to look at a used differential this week to pair with a ZX transmission I just pulled. Was trying to think of things to check before buying. 

  • Check Diff stamp on ring gears
  • Internal welds
  • Metal on the drain plug
  • Damage to spider or ring gears
  • Play in the pinions that hold the spider gears.
  • Damage to the pinion seal or bearings.  

What else am I missing? Thanks to @Zed Head for some initial inspiration here. 

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1 hour ago, 7tooZ said:

What are you building that you need An R200?

Switching to a 280zx 5 speed and am looking to get the 3.9 R200 since that appears to be the recommendation for best acceleration. Currently set up with a R200 3.54 and a 4 speed

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Go on line and use a gearing calculator to speed the effects of different ratios entering the fifth gear ratio of which 5 speed you have. If you have a a .745 and driving on the street you may want a 4:11..

Have you considered a Subaru STI CLSD R180?

Edited by 7tooZ
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I think that he already knows about the ratios and is planning to buy a 3.9 to match the 3.062 1st gear in the 5 speed.  Trying to figure out how to evaluate the quality of the 3.9 diff.

Here are some images of welded diffs.  Some people just do a few solid welds, some people go crazy and fill every crevice.

Here's a funny article about the "benefits" of welded diffs.  Those open diffs are unpredictable!

image.png

Edited by Zed Head

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Pop out the axles and check the quality of the surface that rides inside the bearing.  They're hard to get out, take some tools to pry with.

39/10 is what you're looking for on the ring gear stamp.

image.png

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16 minutes ago, Zed Head said:

I think that he already knows about the ratios and is planning to buy a 3.9 to match the 3.062 1st gear in the 5 speed.  Trying to figure out how to evaluate the quality of the 3.9 diff.

Here are some images of welded diffs.  Some people just do a few solid welds, some people go crazy and fill every crevice.

Here's a funny article about the "benefits" of welded diffs.  Those open diffs are unpredictable!

image.png

that looks like it would make turning very difficult. I guess if you  were drag racing this would be helpful. Would really scrub off rubber if you were to turn with a diff modified like this.

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1 hour ago, Dave WM said:

 I guess if you  were drag racing this would be helpful. Would really scrub off rubber if you were to turn with a diff modified like this.

They do it for drifting.  It's just a cheap hack, just need a welder and some welding material.  I wonder if anyone has tried JB Weld.  That would be a great JB Weld ad.

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20 hours ago, Zed Head said:

I think that he already knows about the ratios and is planning to buy a 3.9 to match the 3.062 1st gear in the 5 speed.  Trying to figure out how to evaluate the quality of the 3.9 diff.

Here are some images of welded diffs.  Some people just do a few solid welds, some people go crazy and fill every crevice.

Here's a funny article about the "benefits" of welded diffs.  Those open diffs are unpredictable!

image.png

Hugely helpful Zed, this is a perfect visual. 

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