Ezzie Posted February 28, 2005 Share Posted February 28, 2005 Finally got this one figured out - thought I'd share it with you in case anybody else ever tries to do this. I needed to change the 3.7 R&P out to a 4.11 for my application (SR20DET motor). The diff is the R200 clutch type LSD from the 1987 Z31 turbo (12mm. ring gear bolts) with the Birfield type CV axles (4 bolt companion flanges). I ordered the R&P set from Nissan - P/N 38100-16S01. This R&P is an OEM gear set used on the later 200SX Turbo (from 4/86) or V6 cars. The pinion gear is noticeably smaller than the 3.7 pinion so the first problem I encountered was the pinion height needed to be raised. I found I had to use the thickest shim I could get from Nissan - 3.63mm P/N 38154-P6036. It is about .24mm. thicker than what was in the diff. with the 3.7 gears. This gave me a fairly decent strike pattern on the ring gear. When I reassembled the carrier with the shims originally in the diff, the backlash was HUGE - the ring gear needs to move closer to the pinion by about 8mm. or so. This got me quite concerned because the stubs of the CV axles snap into a spring clip in the side gears. The side gears are identical on either side of these carriers. If you move the carrier this far, things will no longer line up and the axles won't fit. After doing some measurement, I noticed that the fixed CV stubs are different in length, again about the same 8mm. The passenger one is longer than the driver's side. It just so happens that the carrier is shimmed with a thick 8mm. spacer on the passenger side and a couple of smaller 2.2 - 2.4 mm. thin spacers to adjust backlash. The solution was to move the thick spacer from the passenger side over to the driver's side of the carrier and then shim to get the proper backlash (.005 - .007"). Then I removed the fixed CV joints off their respective axles and swapped them around. Test fit everything and it is perfect. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted March 1, 2005 Share Posted March 1, 2005 Bob - Great info for the tweakers! How did you successfully get the Z31 inner CV off of the shaft? I had no luck with this on the car we did 4.11's in, and ended up using the 200sx CV shafts, as the shafts that came in a 4.11 rear end have the inner joints swapped from the factory. Doug Quote Link to comment Share on other sites More sharing options...
Ezzie Posted March 6, 2005 Author Share Posted March 6, 2005 Doug, The axle is held into the inner (fixed) Birfield CV joint by a snap ring. All you need to do is slide the boot back out of the way and give the back side of the joint a good wack with a brass hammer or some type of slide hammer and they pop right off. Here's a pic of what it looks like all disassembled. http://www.the510realm.com/PNphpBB2-download-id-1331.html Quote Link to comment Share on other sites More sharing options...
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