djnice

On my 2018 Z06 with 3,900 miles the electronic differential is not limiting slip in left hand turns once the car is full warmed up and outside temps are around 90F. In slow turns I get drivers side wheel spin and stability control over reacts causing all sorts of chaos. In sweepers the eLSD is not powering the outside wheel making the car not feel planted. The issue occurs somewhat intermittent. In one afternoon on a 15 minute twisty road it was having the issue and 1 hour later on the same road the issue was gone. Then 4 hours later it came back.

For what its worth the eLSD clutch lock shows 0% in left turn sweepers under throttle and once the car straightens it jumps quickly to positive lock. In the same corner turning right the clutch lock shows ~10% and progressively increases with throttle application at corner exit.

I have tried different driver modes, traction control off, stability off, etc. and it makes no difference.

The car has been to the dealer multiple times this is not throwing codes. I would appreciate if anyone could give me ideas on what to check. I am thinking a couple things:
1. Diff isn't receiving the correct info from yaw rate sensor under left hand turn G forces. Does anyone have service manual info on where the yaw rate sensor is and how its connected?
2. Diff hydraulic system can't pressurize under left hand turn G forces. Any ideas what would make this happen?

Some of you guys that have ran these car on the track for several years now must have come across an issue like this?

dar02081961

I don't know the exact theory of operation for the E-diff.
But I would assume much of the mechanical "locking" portion is the same as LSD's have been for years. If that is the case the only mechanical condition that will not allow both internal clutches to "lock" when they are supposed to (ie accelerating in a straight line) is when one of the clutches is damaged.

I had this problem in my C5. When I took it apart I found several busted clutches in the clutch pack. The differential was working fine however the " locking" effect for that side was non existent. I suspect I busted it when I did several high rpm launches from a standstill and shattered the LSD clutches. That said this happened with over 215K miles on the original rear end at over 150hp above stock. A testament to the strength of rear end in my opinion.

Recommend draining the differential fluid and filtering it through a cloth or coffee filter as you do so. If you find shiny metal particles or residue this is likely your problem. Or since GM is involved they can analyze the fluid sample and tell you right away if there is mechanical damage internally.

Good luck

djnice

I have drained the diff fluid and it has fewer metal particles on the magnet than others (17 GS, 13 ZL1, etc) I have done. I am not sure if the e-diff clutches ride in the gear fluid or the hydraulic side. Good point on mechanical issue. It doesn't seem like it would be intermittent. When its working right it is perfect.

NSC5

The clutches are in the gear fluid so any wear particles from them will show up in what you drained.

Note that if you service the hydraulic side you will need a bleed tool and a scan tool for the procedure. The information is in this thread: https://www.corvetteforum.com/forums...ice-specs.html

djnice

Yeah, I want the dealer to do the hydraulic side. Right now GM is saying no codes = nothing wrong, but we'll see about pushing it further up.

djnice

Well, I pulled this connector apart and checked all wires, sprayed it with cleaner and applied a thin layer of dielectric grease. I have reason to believe this connector is the culprit. So far on Friday and Saturday I can't get the diff issue to come back. We even did a 2 hour road trip on some twisty back roads today.

djnice

Well, almost a year later. Everything worked good at the track last year in hot August and September weather.

Now the issue came back at a cooler track day. Run the first 4 laps with a good rear diff then the last 4 with an open diff.

Rnalecz

djnice, did you ever figure out what was causing your service rear axle issue? It appeared that you thought it was the connector, but the issue came back?

djnice

Yes. The issue came back. It was damaged wires in the harness that runs through the tunnel. A manufacturing flaw and very difficult for the dealer to diagnose. Also not accessible to repair without a major tear down. GM had the dealer pull new wires through the tunnel rather than repair the harness.