Setting backlash - Evo Rear diff install

[Black95TSIawd]

I'm going to start by saying this is my first time ever doing this.

I just installed an Evo 8 rear diff into my LSD pumpkin and have a few questions on setting backlash.

I flipped the clutch packs around to the correct order (after measuring thickness) and proceeded to install the diff using my original viscous LSD's bearing caps and shims. 0.110 inch shim on the gear side and 0.105 inch on the non gear side. This resulted in a .010 backlash which is too much from what i've read online. I swapped the non gear side shim with a 0.101 shim out of the original Evo diff which then resulted in a .008 backlash. Is this suffice? I measured my stock diff's backlash prior to pulling it out and it too had a .008 backlash. I had no abnormal noises coming out of my stock diff. Honestly, outside of dirty fluid, there was nothing wrong with it. It was a perfectly fine yet ****ty Viscous LSD.

Here's my dilemma if this is a no go. Do I go up in shim size on the gear side or continue going down on the non gear side? Does it matter which side gets the change?

 

[doubleclutch]

So I am not sure how the diff is put together, but from my diff building experience (I was the engineer that oversaw the building of 500 of the prototype phase of the new camaro/ats rear axle), Your total shim will determine your bearing preload. So takig out 0.009" off the top may unload you diff bearings pretty substantially. Ideally, you want 0.007-0.009" of backlash, but what is also important is the pattern. If you could upload some pictures of your ring gear pattern, I can tell you if you are going to have issues. Ideally you would have measured the torque to turn of just the diff before messing around with the total shim, and then you could match it. All this to say, you can subtract or add from either side and it will effect the backlash, but most effective is to take away from the side that is the teeth face to decrease backlash. Obviously adding to that same side increases backlash. Increasing preload by adding shim to the side that faces the back of the ring gear will also decrease backlash, but in smaller amounts as it is simply applying more load to the system.

 

[Black95TSIawd]

Update.

Drove the car yesterday for the first time in months. No abnormal noise up to 60mph outside of the normal clutch diff chatter. Reverse wines a bit more, but nothing to worry about.