So my car is not forced induction but it does have a Full Blown 8.8 kit and every post I have seen involving this kit is here. I think the PO was planning on boost but never did or returned it to stock at some point (though that seems counterproductive and cumbersome - intake and exhaust is all stock also).

ANYWAY, I am having a weird issue. I do not think it is with the FB kit, but probably with the diff itself. I am comfortable around the engine bay, but have done little to nothing with rear differential. I have tried searching this board and the rest of the internet and haven't really seen anyone with my specific issue.

Only in the morning, for the first 3 or 4 slow turns of the day, the rear end makes a couple different clunking sounds. Not horribly loud or anything, but enough I can hear it (granted I can hear everything with the top up). After those few turns, she is just fine for the rest of the day. I can let it sit all day while at work and its good to go when I leave... but sitting all night, and a little clunky in the morning again.

My coworker theorized that the diff oil they used may have been thicker than optimal and is just taking its time to coat the gears. This seems logical, but I have no real understanding of how the rear differential operates... any ideas?

Take it easy on the new guy if I F'd up.

 

I don't think a clunk is good description .. I have 8.8 Cnc ... It sounds a little different than oem .. Especially with top up .. Make video of the noise and post .. Also check fluid .. If it's an internal clunk I would think there would be debris in the fluid .. My 8.8 takes thick fluid too

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Sorry, I guess I just do not really know another way to describe it. I can try to take a video, but I doubt it will be loud enough to hear (I have 18s with wider tires that are pretty loud as well).

If there were debris in the fluid, wouldn't it make the clunking noise regardless of time of day rather than just the very beginning of each day?

 

I use 75w150 severe gear in my 8.8 (I've had the FB kit on two cars now). My diff is super loud and a little clunky; no issues thus far though (beyond the noise haha). No metal shavings/etc in the diff when I drained the oil.

OP, has your car made the aforementioned noises since you bought it, or was this a new occurrence?

 

To me clunking can come from axel play diff play tranny play .. Like just slow motion clunks .. Nothing at speed .. Put your car up and spin the rear wheels back and forth and listen for a clunk .. As said mine is noisy but no issues so far and I have done the oil 8 times already never anything more than dust on the magnet ..

 

Well I just bought it Saturday but didn't hear the noise until Sunday (I had him meet me so the car had warmed up). It is only in the very beginning. I have never changed the rear diff oil, but it doesn't seem overly difficult so I think I will just give that a shot on Saturday and keep an eye on the quality of the old oil.

OT: I am a bit of a Linux guy myself, though much more of a networking guy (CCNP). Cool stuff.

 

is this clunk noise more noticeable going straight or turning?

 

Only when turning and only initially in the morning.

 

Sweet! Congrats on the CCNP! I'm a Red Hat employee, so it might be difficult for me to articulate my need to take Cisco exams haha (although, I would like to go that route (ha) at some point).

Do you know what cover is on your diff? The stock Tbird (steel) case doesn't have a drain plug, so you'll need to pump it out.

 

Sweet! Congrats on the CCNP! I'm a Red Hat employee, so it might be difficult for me to articulate my need to take Cisco exams haha (although, I would like to go that route (ha) at some point).

Do you know what cover is on your diff? The stock Tbird (steel) case doesn't have a drain plug, so you'll need to pump it out.
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I got under there the other day and there was no drain plug, just a "8.8" marking on the bottom right. I will Amazon myself a pump and the 75w150 fluid (any particular brand yall recommend... redline?).

OT: Some basic Cisco certs certainly can't hurt. I usually advocate most folks early in their IT careers to get really good at one thing and learn the others as you go.

I am now actually making my way into the Nexus world (basically just Cisco but working heavily with virtualization platforms) but always force myself to use a Linux distro for my lab machines so I don't lose the little touch I have with it haha.

Thanks for the help here fellas... I doubt its a big issue and I know I am unboosted clouding yall's forum up!