Bringing up the Rear Part IV

1 Nov

The 4.3 rear is now finished, and in transit back up north! This was an adventure to say the least, and essentially represents a bunch of parts that otherwise should not fit with one another. Ben @ Puddymod sent me some final pics of some more of the custom things that had to be done. I figured I’d share them, just so you guys can see what was involved

On the ring and pinion setups, you have a crush collar. This collar is a use-once part, and basically serves as a base that lets you set the torque of the pinion nut consistently. Here you can see the standard crush collar, vs the one that had to be machined for this setup


Here you can see how everything stacks on the pinion itself – just gives you a nice visual to show where the bearings go


Even the shims needed to have the gear mesh so nicely had to be custom done


Because this involved so much custom work, Ben actually made a fixture to make things easier. A prybar is used to set the lsd/ring gear assembly into place quickly and evenly, and the fixture holds it in place



After the bearing caps are reinstalled a backlash reading of 4.5 to 5 thousands is measured, note the sweet gear to gear pattern


Total turning torque on the assembly is 30 inch pounds with 270 foot pounds on the pinion nut


And there you have it – the inner workings of the 4.3 setup. I’ll be using the SPL Pro Differential Bushings with this setup, and I’ll also be testing out a new Urethane Transmission Mount as well, which I am really looking forward to.

Once everything is installed, hopefully by next weekend if time allows, I’ll do some in car videos and post them on our Youtube Channel

Thw questions we’ve gottan alot: Can you do this for me too? The answer is yes. The second question is “how much is it?”. The answer is, unfortunately, insanely expensive. Between the custom parts that had to be made, to the sheer hours of labor involved, this is easily several thousand or so in labor (parts not included). So if you’re serious about it, and it’s on your ‘must have’s”, drop us a line at For a brief period we were able to get our hands on a drop in 4.3 final drive, but sadly, the part was discontinued from our Japanese supplier, and no more will be produced. While it was in and of itself very expensive, it was still less than 1/6 the cost of everything that has gone into this. One of those situations where you are so deep into it, you have no choice but to finish.


3 Responses to “Bringing up the Rear Part IV”

  1. Hollywiz November 19, 2009 at 5:03 PM #

    Will Z1 be offering this custom fabricated 4.3 setup for customer purchase?
    Hopping up from the 4.08 would be lovely ; )

  2. Adam November 19, 2009 at 6:34 PM #

    Sure, if someone wants to buy a complete assembled pumpkin with the 4.3 installed and an aftermarket LSD, we can do it. Or, we can sell this one (it’s not yet in the car) for $5000, shipped in the 48 states.

  3. Hollywiz November 28, 2009 at 12:56 AM #

    Very good to know.
    I recently dropped an os giken diff in my rear so I’m just looking for the gearing and associated parts.

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