Good info!

 

it's not a chatter "issue" its just simply the noise a rear differential should and will make

 

OK, I get that a more locking rear diff will 'bark' more in a parking lot when you are asking one wheel to retake significantly more often than the other, and the diff, or an LS diff, is doing what its designed to resist that. So bark, or chatter, or bucking, whatever the folks call it, I would expected the stock rearrange mod is less of that than the 12 plate WEIR.

If for not other reason that some posts have indicated they didn't notice much difference.

I am in the middle of the mod. It gets down right easy with a helper rather than trying to vice everything in place.

I have some questions about the 'groove' mentioned in 27-51 of this post (step 8). My photo hosting crap is not working anymore so I will have to link to the other post...
https://www.evolutionm.net/forums/9410547-post613.html

So I suppose this could happen if you flip the whole assembly around by accident while fiddling with the disks. Not that I am talking from experience or anything .....

So what would actually happen if that groove is in the diff in the car the wrong way? (facing up being wrong I guess in the diff). Can anyone elaborate on that. Mechanically I couldn't figure it out.

I have plenty to time to correct it, but curiosity on this has me wanting to fully understand the mechanical functionality.

I am great a taking stuff apart, its the reassembly that gets messy, because I am usually several in by then.

Here is the pic

 

Update:

This past week after honing in on the noises the diff magically stoop making any chatter noises. Kind of weird but cars do things like this sometimes. I am going to see if the car starts to make noise again after another event.

 

Instead of the diff "locking up" on acceleration the diff would only "lock up" on deceleration.

 

Sorry for the late reply. I haven't tried diff acd modes. I'll try today and see.

 

Thanks sirnixalot. I corrected my 'groove' orientation. I was trying to learn how to measure the runout and backlash as mentioned in this post and the others linked from here about the rear diff mods. I read the FSM on that, but wanted to make sure that:

Backlash is the play between the pinion and drive gear, correct? So you would be trying to measure the gap or wiggle space of the drive gear while you have the pinion gear fixed. The amount the drive gear could move back and forth is the tolerance the FSM is referring to. Correct?

Also, just form a theoretical standpoint, some backlash or play is always necessary. Otherwise perfect fitment is actually binding the gears, correct?

If adjusting is needed I don't think I can do that, but it looks like a shim goes behind the bearing, requiring removing the bearing. I was expecting the shimming to go between the bearing and the washer (part 20 in the FSM page 27-40), but it doesn't seem so according to the FSM.

 

Hmmm. I was wondering about this setup of incorrect discs
Was there any recalls in regards to this.

 

It was done purposely. No, there is no recall.

 

but why

 

We don't know for sure. The main theories are

1) To give the car power understeer rather than oversteer, which isn't as "dangerous" if it surprises you on the street.

2) To make sure the diff doesn't make any noise and risk having to warranty a ton of diffs for clunking even though it's working properly.

 

Did this mod in about 4 hours the other day then took a trip out to Julian through the mountain twistys and it was definitely a noticable difference, and there was not a single peep of chatter. If you haven't done this mod yet get a buddy and a case of beer and knock it out. Simple and cost effective.

 

Was wondering how many of you slightly overfilled the DIFF, based on another thread here, and I believe info on the Shep and TRE sites. They all have DiFF mods which include the deck, and a site for the level etc. The concept is to tilt the car down and then fill to get slightly more fluid in the DIFF.

Is there any downside to overfilling the DIFF slightly?

 

I filled my diff up while the rear end was jacked up about 8 inches and so far so good, no leaks.

 

It's not an acronym. You don't need to capitalize.