S-tronic Gearbox question

[mrbubba]

My 2010 S4 has just had a Gearbox oil service, as the box was getting very clunky when changing gear and not smooth at all moving off in 1st.
Since coming back, the issue is still there and I've noticed now, that when the gearbox is engaged (in gear), the engine revs start to pulse, from 1k to 1.5k. if I take it out of gear, the engine idles normally.
This makes edging forward in traffic and reversing very difficult, it's like a learner driver kangarooing away from a junction.
I was crawling along in traffic the other evening and it was embarrassing, the car would kangaroo at low speed. Once you get moving, going through the gears it's nice and smooth, but you can't just cruise at a set speed, as I can feel the pulsing of the revs

Any ideas? Car has covered around 96k

Sent from my CLT-L09 using Tapatalk

 

[Cerbera9]

I had exactly the same symptoms esp when the gearbox was hot ie in traffic with little airflow. Turned out it was diagnosed as Mechatronics failure, the unit is unable to maintain oil pressure when the oil viscosity changes due to the heat and can’t clamp the clutches correctly causing them to slip and permanently wear.
Just had my gearbox repaired, recon Mechatronics unit, gearbox removed and flushed and new clutch pack, total cost £3000.

 

[mrbubba]

I had exactly the same symptoms esp when the gearbox was hot ie in traffic with little airflow. Turned out it was diagnosed as Mechatronics failure, the unit is unable to maintain oil pressure when the oil viscosity changes due to the heat and can’t clamp the clutches correctly causing them to slip and permanently wear.
Just had my gearbox repaired, recon Mechatronics unit, gearbox removed and flushed and new clutch pack, total cost £3000.

Hmm well can't afford to spend 3k, so guess the cars going to be moved on

Sent from my CLT-L09 using Tapatalk

 

[Cerbera9]

I would suggest getting a professional diagnostics done first, you might be lucky and just need The Mechatronics unit changing which is a lot cheaper!

 

[youngsyp]

You could try a TCU reset, before you start throwing money at it. Check out this for details.

I just did one, as a matter of course, after an S-tronic oil/ filter service. I had a brief, slightly annoying pause on heavy throttle, manual upshifts between 2nd and 3rd. I put it down to the gearbox doing it to restrict torque. It's early days but it seems like the TCU reset has rectified that and I now get the same experience from all upshifts, everything else being equal.

If your S-Tronic is at 96k miles and has never had the TCU reset, it would be well worth doing, as it does a number of things including calibrating engagement points for the clutch plates.

Paul

 

[Meemo]

the stronics are dry clutches rather than integrated wet clutches i think (?) in which case, maybe a slightly lesser bill of a clutch pack(?) if the software reset doesnt do the job, seen revs bounce when a clutch is worn close to failing before (not on an stronic but a manual), let us know how you reset goes

 

[youngsyp]

the stronics are dry clutches rather than integrated wet clutches i think (?) in which case, maybe a slightly lesser bill of a clutch pack(?) if the software reset doesnt do the job, seen revs bounce when a clutch is worn close to failing before (not on an stronic but a manual), let us know how you reset goes

The DL501 is a wet clutch design, which means wear rates on the clutch packs are very low. The OP's issue, if not fixed by teh reset, will be down to the mechatronic unit, most likely.

Paul

 

[Meemo]

The DL501 is a wet clutch design, which means wear rates on the clutch packs are very low. The OP's issue, if not fixed by teh reset, will be down to the mechatronic unit, most likely.

Paul

Good to know, gonna hijack a little, sorry. Are the later s5 b8.5 dry clutch? i had it in my head the dual clutch in mine(2015) was as to be similar to a manual setup but with the benefit of an auto... if not no idea where i have got this in my head from.

 

[youngsyp]

Are the later s5 b8.5 dry clutch?

Nope. The B8.5 S5 uses the same DL501 S-Tronic as the equivalent S4 and B8 S4. There are variations within the DL501 design, between model years but, the basic design is the same.

Paul

 

[Cerbera9]

I believe the later gearboxes and an additional external cooling filter on the side

 

[mrbubba]

You could try a TCU reset, before you start throwing money at it. Check out this for details.

I just did one, as a matter of course, after an S-tronic oil/ filter service. I had a brief, slightly annoying pause on heavy throttle, manual upshifts between 2nd and 3rd. I put it down to the gearbox doing it to restrict torque. It's early days but it seems like the TCU reset has rectified that and I now get the same experience from all upshifts, everything else being equal.

If your S-Tronic is at 96k miles and has never had the TCU reset, it would be well worth doing, as it does a number of things including calibrating engagement points for the clutch plates.

Paul

Thanks for the link. Is there a way to do this in OBDEleven? I don't have vcds, but use do use OBDEleven.
I was researching this reset before I saw your post, but I can't find the option anywhere. There is a reset option under transmission, then 3 options, hard reset, soft reset and then one about key out (can't remember the exact words)

None of those do anything, I get the message (11) function unavailable.

I had just come back from a 30 minute drive, so temperatures should have been ok, the engine was idle and foot on the brake pedal, but nothing.

Sent from my CLT-L09 using Tapatalk

 

[youngsyp]

Thanks for the link. Is there a way to do this in OBDEleven? I don't have vcds, but use do use OBDEleven.
I was researching this reset before I saw your post, but I can't find the option anywhere. There is a reset option under transmission, then 3 options, hard reset, soft reset and then one about key out (can't remember the exact words)

None of those do anything, I get the message (11) function unavailable.

I had just come back from a 30 minute drive, so temperatures should have been ok, the engine was idle and foot on the brake pedal, but nothing.

Sent from my CLT-L09 using Tapatalk

I'd find someone near you with VCDS , just to ensure the right procedure has been followed. You can use the VCDS map at the top of the page.

Paul