hisvett

This just started the other day, though it had something to do with getting the car aligned. At freeway speeds (60-70 MPH) after driving over a bump or uneven section of pavement, the car's rear sways (sloshes) like a small boat getting hit by a swell from the side. The drivers side rear dips, then the whole rear squats and then rises on the passenger side. This all happens while the front of the car is stable.

I believe what is happening is the electronic differential is locking and unlocking. Watching the center stack with the eLSD pulled up, the percent drive between the L&R changes (increases) by about 2% per 10 MPH (45 MPH=about 10%). I never noticed this before....is this normal? Also the bar scale on the bottom will sometime swing to half scale (in the green) and at times swing full scale (into the red) showing major wheel rotation difference between L&R. All this happens under normal acceleration from a stoplight. I'm going to take it out on the freeway and watch the eLSD screen.....just to see what what's going on.

I'm taking it in on Monday; hopefully it can be fixed before heading to COTA on Friday.

Before making guesses, note;
Alignment was rechecked and numbers are the same as the last 45K miles.
Tire PSI was checked, same on both sides.
The problem came on all of a saddened.
Doesn't "slosh" nearly as much when moved to "Sport Mode" (Mag Ride).....probably because the stiffer shocks slows the action down.

Anyone else witness this?

AORoads

my guess: something was left loose from alignment.

13brv3

If we're guessing, I'd say bad shocks. The description seems like what I've felt in other cars when the shocks start to go bad, and it would make sense that setting it to a stiffer setting would help. Does it look like there's any fluid leaking from them?

Good luck,
Rusty

JerryU

Over the years when I have a problem I always look at what I did last! Often doesn't look like it could be the issue-but often is!

13brv3

Sounds to me like he had the alignment rechecked after the problem started, to rule that out as a cause. If I'm reading that correctly, the alignment guys should be off the hook :-)

Rusty

hisvett

Thanks for playing along but it is not the alignment; it has been rechecked and shows the same numbers I have been using for the last 45K miles. I can't say differently when this started because it didn't show up until I got on the freeway running at 70MPH. All I can deffently say is it started sometime between returning from the Bash and driving to a local track two weeks later.

If you have a eLSD, does yours do this; I seem to remember it staying at "Zero", not increasing as speed increases.....not to mention the scale at the bottom swinging to the right at role out. Thanks for your help.

13brv3

I decided to save some fuel and just search instead of testing, though you can be sure I'll watch this the next time out :-)

Here's a thread that shows blurry pictures that match exactly with what you're seeing.

https://www.corvetteforum.com/forums...d-percent.html


Below is a quote from one of the threads I ran across. This seems like accurate info, but I can't guarantee if of course.

Looks like what you're seeing is normal.

Rusty



It shows two components on different axes:

- % of engagement of the clutch packs
- % slip between the two wheels

I think it confuses a lot of people because driving straight down the road it'll read 30% and people will think that's the amount of slip, but that's the amount of pressure on the clutch packs locking them together.

So, the top number is the amount of LSD lock, and the bottom is a sweeping graph showing the amount of slip.

hisvett

That add up.....Damm, now I have to keep looking for a cause

Thanks

Kenafin

This may or may not be it in your case but it's a quick check worth looking. See where the fluid level is in your diff.

I had some symptoms similar to what you're describing along with a general feeling of the car floating and just not feeling like she was handling right. Took awhile to figure out after checking everything suspension (alignment, shocks, etc) - finally figured it out when she popped a quick warning about low fluid in the diff. Filled the diff to the correct level and all the weirdness with the suspension went away.

hisvett

Thanks for the tip; I have it up on jack stands right now draining the gear oil....it was way lower than the fill plug (couldn't get to the oil level with a zip tie). I have 3 qts. of oil coming today...finger crossed this will fix it. If it does, I will be paying my dealer a visit Last week they said it was the rear shocks and would be happy to change them for $1500. Thanks but no thanks; I found new OEM replacements on the web for $300 each delivered. I put them on yesterday, no difference in ride THANK YOU MR. GOODWRENCH!

I'm catching every last drop from the diff and will be checking the fill...or lack thereof. More later......FYI, I have a new set of Mag Ride shocks for sale

ersatz928

I don't think the diff has anything to do with your problem.....either the alignment is off, or there is something loose (or bad bushing) in the rear suspension.

AORoads

I'm guessing this is not one of the cars checked at PDI for low diff fluid as was reported early in the C7 run.

But what you are saying is that after the alignment, you took it back to the dealer complaining of/indicating there might be something wrong with the diff, and no one at the dealer checked its level, correct?* Instead, they said, you need (very) expensive new shocks.

Yes, in that case, I'd think you are entitled to have some "spirited conversation" with the dealer/service dept./technicians.

Tell us how it all turns out.

*I've seen where keeping the car level is important when checking/replacing the fluid-presume you know that, of course.

hisvett

No on the diff/dealer; I had one of the techs ride with me, I let him decide on the cause. That's when I left the car and they came up with "needing shocks".

Checking for low fluid in the diff came from "Kenafin"; after changing the diff fluid out....and by the way, it WAS more than a half qt. low I drained every drop out and refilled the qt. containers the oil came in; 2 qts. 13 ozs. is what came out. It is listed as taking 2.9 qts.; I'm just a little bit at GM. If you recall, the 2014's were having issues with short fills and had to recall a bunch to recheck. My car BOD is April of 2015; you would think the word would have gotten the guy that was filling the diff's after almost 2 production years!

Have I damaged the eLSD by running it so long at a half qt. low? I have all the oil that came out; no metal flakes, just looks like it has been run for 48K miles. I will be paying a visit to the dealer on Monday. AND YES, the car was dead nuts level; it took just a touch less than 3 qts. to fill the diff.

BTW, the test drive with the new oil didn't solve or change the symptoms.....the saga contuses

djnice

The video doesn't work. Was your slip bar graph pegging out at 30% for no reason?

1LENICK

hi did you ever find a solution to this issue? My 2022 ss 1LE is experiencing the same thing and it’s driving me nuts! Please let me know.

stingraynick75

https://www.corvetteactioncenter.com...nter-1458.html

1LENICK

thanks but it turns out it was an alignment issue I found in another one of his threads!