[pcthedruggist]

I have a 2016 550 xdrive and today I notice with transmission in sport mode at higher rpm the shifts are very jerky, like something slips then catches. I noticed a similar thing at low speeds when it downshifts and thought it was odd, but it’s a recent purchase and I’m not familiar with how the 8 speed behaves. This was the first time it happens at other times. Anybody had similar issues? Differential? Transfer case? It’s under warranty still so I’ll take it in, but I’d like to have some idea of what it could be so they don’t blow me off.

Thanks!

[wcr3d]

That transmission is said to be one of the best ever, should be smooth through all the range.

[pcthedruggist]

That's what I've heard, so I'm thinking it's something other than that. I'll keep an eye on it, just curious if people had similar experiences.

[wcr3d]

Try a search here of the web and you'll find plenty of similar issues.
Typically it's a low speed issue, most notable is around 2nd gear downshift.
Some say just a fluid change was their fix, usually it takes a kit to fix.

[Surly73]

Well - if you've got it in full SPORT+ and you have the 2TB sport automatic transmission you may be able to feel the shifts in high rpm situations. These transmissions are very good, and can/should be very smooth, but they have different modes of operation.

I am not equipped with these options, but I do have xHP transmission software, so I know that the most aggressive shift programs (i.e. the ZF factory parameters for the most aggressive sport shifts) do "jerk" the car. The operating conditions you describe could be using these shifts.

Further, since the car is "new to you", might it have an xHP transmission flash from the previous owner?

You don't necessarily have any problems, especially if it's only high RPM, SPORT mode, aggressive shifts that you feel. On any "new to you" vehicle, full fluid and filter changes head to toe are not a bad practice. ZF recommends no more than 100,000km/60k mi between fluid and pan changes.

Do some googling for xHP and check their FB page. They have posted several articles about how the ZF 8HP transmissions operate. You can learn some useful information about the car (even in fully stock form) from what they've shared.

[pcthedruggist]

It's not a hard, crisp shift though. It really feels like something slips then catches. I've driven the car hard before and just noticed this recently. I'll see if it continues in the coming days for sure. The car was a lease return from an older woman so I doubt it's xHP tuned. I'll check out their page though.

wcr3d--I saw some of those and tried the reset procedure with no luck. I'm less concerned with the low speed issue than the recent one.

Somebody on a FB group said he had similar symptoms and they had to replace his transfer case. I'll keep researching and take it in soon if it continues.

Thanks for the input.

[Surly73]

Originally Posted by pcthedruggist

It's not a hard, crisp shift though. It really feels like something slips then catches. I've driven the car hard before and just noticed this recently. I'll see if it continues in the coming days for sure. The car was a lease return from an older woman so I doubt it's xHP tuned. I'll check out their page though.

wcr3d--I saw some of those and tried the reset procedure with no luck. I'm less concerned with the low speed issue than the recent one.

Somebody on a FB group said he had similar symptoms and they had to replace his transfer case. I'll keep researching and take it in soon if it continues.

Thanks for the input.

Fair enough. Fluid/filter replacement would still be a good idea nevertheless. I've witnessed lots of strange behaviour on 5HP and 6HP models which were fixed by fluid/filter.

Hopefully not transfer case!