4 weeks ago Chris Fain (machismo) and I did a 2 car diff swap. He got the 4.10 Torsen out of my miata and I had Bo put 4.3 gears into a Torsen I got on ebay. I purchased a set of polyurethane SuperPro Diff Bushings from Gary@trackdog. I also had a set of DriftingJellyfish (DJ) UHMW diff mounts that were gonna go in Chris' car. After looking at the size of the DJ mounts compared to the SuperPro mounts, we decided against them. The DJ mounts were shorter than the SuperPro bushings and since the SuperPro bushings were equivalent in size and shape to OEM bushings we went with the the SuperPro. The DJ bushings also lacked a metal sleeve in the center.
A great method for removing the OEM bushings, without a press, is by drilling them out with a powerdrill. Gary recommended this method and it did the job.
Chris and I jacked both miatas up, tail to tail, and began the removal process on both cars. We had to pull the torsen in my '94 to place in his car. The whole job from start to finish for both cars was about 9 hours, which is fairly slow since we had to get parts throughout the day.
Both cars received 1 quart of Motul 300 Gear Oil for the diff.
The 4.30 gears are awesome for an n/a miata! I had them in my red '96 and I forgot how great they were. First gear comes and goes like a boosted miata, especially with the lightweight clutch and flywheel concept. If any of you guys are planning on staying n/a, I recommend the 4.30's.
