S550 Slop, Clickity Clackity Clunkity!

Dominant1 said:

The remedy is to get rid of the torsen diff and upgrade to a tru trak when they make one for the super 8.8 if they haven't already!

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That's funny stuff, right there!

The Torsen units actually have pretty tight backlash for the type of differential - being helical gear, without preload springs to mask the differential gearing lash.

When you check lash like shown in the video, you're checking system lash. That is, you're picking up everything that contributes out to the hubs, including all spline joints. On cars with the Torsen, its worth repeating that the 3.73:1 gear ratio multiplies system lash more than lower numeric ratios do, so the same level of lash in the axle components will feel worse. It would measure about 12.5% more than with a 3.31 ratio.

It was pointed out above that the ring and pinion lash is set somewhat high on these from the factory. There are also 4 spline joints on each CV shaft, though I know that the end that goes into the diff tends to be fairly tight. My point is that you should keep in mind that there are lot of factors involved here. With that said, Ford tends to allow a looser set up then, say GM does. Compared to another similar project that I worked on, they (Ford) probably has at least 50% greater lash in the axle as a system...:(

Mine has alot of slop too. Hoping to get rid of that when i go to 373s and have them properly setup. Also...check your rear hub bearings. Mine are shit at 27k. Jack the car up...and see if you can wiggle the tires...mine arnt making any noise but i find it hard to believe 1/8" slop at the tire in all directions is normal..

LX1 said:

Mine is bad. The factory fluid only lasted a few track days and it got crazy loud. Went with a heavier weight fluid and it has quieted down a ton. Still sloppy but not as noticable. And I am running Bmr delrin cradle bushings and poly diff bushings.

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Just a guess... maybe the heavier weight fluid has a cushioning effect when the slack is taken up?

Do these super 8's have drain plugs?

At first watching the vid I thought to myself my '11 with 3.73's is worse than that, but then Kelly really started cranking on the pinion and I said out loud "holy shit-snacks!"


It has been too long since I've done a gear install but I should probably start practicing here at the shop for when local guys want them checked/swapped.

You could always swap out the entire rear end with a regular 8.8 or fabricate it for a 9in rear.

Granted youll lose the IRS but it might not be a terrible thing.

Couple comments here:

- Yes, that is definitely the noise I've talked about in a thread or two. Once you take off the DS and turn the pinion like that by hand, you have that AHAA moment. THAT's the noise I'm hearing. Note, this was after going to a 1pc AL DS. Stock 2-pc rubbery POS masks it.

- It was annoying af with clutch in up/down shifting slowly in traffic. However, I noticed that after lowering the car and a couple hundred miles on the BG diff fluid this noise is much softer in the cabin. I still sometimes hear it, but it's more muted and tolerable.

Gee said:

Couple comments here:

- Yes, that is definitely the noise I've talked about in a thread or two. Once you take off the DS and turn the pinion like that by hand, you have that AHAA moment. THAT's the noise I'm hearing. Note, this was after going to a 1pc AL DS. Stock 2-pc rubbery POS masks it.

- It was annoying af with clutch in up/down shifting slowly in traffic. However, I noticed that after lowering the car and a couple hundred miles on the BG diff fluid this noise is much softer in the cabin. I still sometimes hear it, but it's more muted and tolerable.

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I been noticing that the noise do die down with some miles and the BG fluids. Thanks for confirming, thought my hearing was going bad lol.

It's a feature.

Thanks for posting this. Now I can explain to my friends what that noise is as they think I don't know how to drive.

I'm going to BG fluids in a week or so, and I'm going to check the CV joint on my driveshaft -- this is the second one from DSS on my car -- I was going to ask Kelly about the Shaftmasters piece he has on his black car -- it's lighter than my CF one, and I have no idea when I will be putting a blower on my car -- if ever -- plus it looks like they sell all the Spicer hardware to rebuild them without sending it out somewhere? My clunk may not be related to these noises -- no sound at work -- but hey @BMR Tech -- do you still like the Shaftmaster driveshaft on your Stockonaut car?