Is my differential about done?
 

I have 172k on my 2013 six speed manual FRS. When you build up that many miles on the same 75 miles of road twice a day for 6 years, you get to know your car like you know your wife. Any change is perceptible.



Well, about 3k miles ago I noticed a very slight clunk when I changed gears (mostly lower gears). It's very, pronounced now and most obvious when backing out of a parking space and going into first. After discussing another issue here I thought it might be a u-joint, but at my last oil change they checked it and they were all tight.

So yesterday, I jacked up the rear end and simply spun a tire back and forth with my hands while looking at the drive train. What I have is a TON of slop in the differential. I mean the tire turns something like ten degrees (maybe more) and everything else stays still. e.g. the driveshaft does not move. This is the case regardless of which wheel I move.

I don't really know how this LDS works, but that seems like a LOT of slop for any differential and it seems to be getting worse. Oddly, it really doesn't make any more gear (whining) noise than it did at 100k.
Any thoughts from someone that can see in their mind the contents and function of this LDS?

Differentials usually have a bit of free play, are the differential bushings and subframe bushings ok? Usually with a failing diff you'll start to get growls and whines, or play that is non rotational.

BTW the initialism is L.S.D. for limited slip differential. Nobody knows how LDS works.

It sounds like the bushings are bad.

If you are not getting a noise "wiirrrrrrr"/howl/whine while driving(acceleration or decel) the odds are your diff is fine. Could drop the fluid and see what comes out to be sure. Seems like you have a driveline(u-joint) or a bushing issue.

There is tons of slop in the diff. I have asked about it before too. I now have an 18' diff and my car, it still has tons of slop too. I had a similar clunk a while back and it went away when I re torqued the CV axle nuts and restaked them.

When I turned the wheel back and forth, the axle was solid against the diff housing and the diff did not budge. Also, the driveshaft was motionless.


I don't know how bushings play into a differential, so an educated guess is to check to see if the input shaft has "in and out" play. I guess...


The reason I zeroed in on the diff is because the input shaft didn't budge, the housing didn't budge, and the output shaft stayed in place except for the turning motion. It just seemed to turn a really long way.


And, again, the reason I'm doing all this stuff is that at the dealership they said the drive shaft and u-joints are fine, but I am definitely getting a clunk that didn't used to be there.

Now we're getting somewhere. It seems to come from the passenger side - and I recently replaced that wheel bearing. I didn't torque the bolt. I simply put it on really tight (My torque wrench was ruined and I since bought a new one).


Do you know what the torque spec is on that thing?

HA! I found this thread on it: https://www.ft86club.com/forums/showthread.php?t=94840


143 ft lbs.


And the comments there are very promising. I never thought to search on that before creating this thread.

It’s 143 ft-lbs.


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Put in some diff oil. That's what you need

You mean it may be getting dry? I didn't see any sign of any leak.

These torsen diffs behave like open diffs when up on jackstands. If you spin one wheel forward, the other will spin backwards and the driveshaft will remain motionless.

i think ive had that cluck/metallic click for like 80k miles. i just turn up the volume. i plan on replacing the entire rear end/axels whenever the dif actually goes boom. im at 150k miles 0 problems so far

as far as slop goes, the last tim i checked it wasnt like 10 degrees of slop but there is some there. maybe a couple degrees

this makes me want to ask if you changed the diff oil and transmission oil recently.