Diff OPF play

[Cubieman]

I was under the car tonight and found that the passenger side diff. output flange has a bit of rotational play as well as some up/down play whereas the driver's side seems solid as I imagine it should be.

https://youtu.be/8ZmcfuX2wF0

I will admit I am not incredibly well versed on the inner workings of the diff so I would like someone with a bit more knowledge to let me know what the issue may be here. The OPF itself is rotating and moving up/down slightly so it's not an axle/CV issue.
I understand there should be some lash but the fact that the driver's side OPF doesn’t move at all has me thinking maybe the diff. clutches are going?

Looking to find out how big of an issue this may be and how involved, (i.e. diff rebuild) this may be to fix.
Thanks.

Edit: I see there was a TSB released in regards to this and driveline play creating the "clunk" sounds in low gear/RPM situations. The TSB suggests that it's normal for the passenger side OPF to have some rotational play as compared to the driver's side but mine also has some up/down play as well.

Also, just read into a few other diff related threads currently active and see this is a well known issue, may try the racingdiffs.com "free play shim" if/when diff is opened. This diff. was rebuilt in 2015 while under previous ownership so I would hope the diff is OK for a bit, that slop just seemed excessive.

[slavik1988]

It is a common issue with these diffs. I pulled mine with 55k miles on it and it had quite a bit of play on the right output flange. Mine runs great and I am not overly concerned yet until I will get to rebuilding it.


There is a shop that parts out them locally to me and sees these with lower mileage diffs as well.

[jet_dogg]

It's so funny how there are so many issues with this platform yet we remain vigilant lmao.

[bigjae46]

There is going to be some play because there is backlash in the gears. There is a specified amount.


Sent from my iPhone using Tapatalk

[kermmmit7]

I have had the same issue in my M3 when I hit 100k - my mechanic recommended me to rebuild differential - I used diffsonline. My other car has 86k mileage and there is no play. I guess you need to rebuild your differential soon.

[sapote]

I was under the car tonight and found that the passenger side diff. output flange has a bit of rotational play as well as some up/down play whereas the driver's side seems solid as I imagine it should be.
I understand there should be some lash but the fact that the driver's side OPF doesn’t move at all has me thinking maybe the diff. clutches are going?

The good news: yours is fine, as long as no oil leak on the output flange seal.
The explanation: All diff spider gears (driven by the rods on the carrier) and side gears (these driven by the 4 spiders and connected to the axle splines) have a lot of backlash and I don't know why all manufactures wanted to have that way. So why the RHS flange has more rotation backlash than the LHS? For a normal non-LSD diff, the left and right flanges have exactly the same rotational backlash, but not for our car diff. The left flange spline shaft is longer as it mated to the side gear and also to the clutch stack center core. The clutch center core is locked solid (your hand is too weak to make the clutch slip) to the carrier. Actually there is still small backlash between the flange splines to the center core spines, and of course the carrier/ring gear has some backlash to the pinion shaft. So you should feel some small backlash on the left flange which is the pinion/ring gear lash.
So with the left side gear locked by the clutch core, all of the spider/side gear lash now transferred to the right side flange, which should be the same as any non-LSD output flanges. I don't like the radial plays (up/down) on the right side, but this is the way it was designed. The only way to cut down the radial plays is to have a custom roller bearing outer race and the cover made with smaller inner diameter. This inner diameter is the bearing surface for the output flange shaft to run on. More radial plays kills the oil seal faster on the right side.

[sapote]

Those spiders and side gears only turning when car taking the turns, so they are very much stayed dormant most of their lives. So why stock diff still have too much radial plays on the output flanges (side gears)? The "Play Fix" conical shim from Race-Diff will take out all of the plays, but this is gimmicky to me, as when under load the side gear will push the conical shim to flat shim with little effort. The owners feel zero plays but during driving, all of the plays is there.

If someone is about to use that "Play fix" shim, I would suggest to just select the right thickness normal flat shims to take out most of the plays (tighter than a new factory unit). This will not cause any new noise on straight drive, as the gears are not rotating. I'm interested if the tighter clearance on the gears mesh will cause any noticeable whirring noise during a turn. This is the only side effect I could see with tighter clearance, but this has no harm to its operation. What are the gains? less backlash on the drivetrain and so less clunk noise during load changes, and longer oil seals life on the output flanges.

[Flat-Six]

Same issue with “play” on pass side. I was told it was normal as well from a master tech that saw a lot of these with low miles. No leaks so I don’t worry about it.