[M3 Eater]

I have 80k on my tuned automatic and it seems to be bumping a bit when it downshifts. Also sounds like a clutch slip when going from 3rd to 4th gear. I have reset the drive by wire( used to work well) but it seems to return to bumpy downshifts quickly after. The trick is, BMW knows the car is worked over. They pick and choose which warranty work they will do on my car so there is no benefit to removing the mods. It\'s just more wear and tear on clips, bolts, an hardware. It makes more sense to leave it as is and pay when they say pay. Any thoughts??? Besides picking up the new 1M.

[samchoi604]

Have you considered AT fluid change?

[chromisdesigns]

Originally Posted by samchoi604

Have you considered AT fluid change?

+100 this would be the first thing I'd try -- the 100K mile service interval is BS, IMHO.

Be sure and change the pan, which contains an integral filter. Because you can't drain the torque converter, you still won't get all the old fluid out, but it should make a big improvement.

[queensfield]

Bad contacts in the pins and wiring in the mechatronic sleeve is a possibility too. When changing ATF and pan/filter, take a look at the mechatronic sleeve to make sure all pins are making contacts and the sleeve is not leaking.

[Turkeybaster115]

Originally Posted by chromisdesigns

+100 this would be the first thing I'd try -- the 100K mile service interval is BS, IMHO.

Be sure and change the pan, which contains an integral filter. Because you can't drain the torque converter, you still won't get all the old fluid out, but it should make a big improvement.

To get the fluid out of the torque converter, you can just do multiple drain and fills, and drive around in between.

[F32Fleet]

Contact a ZF rep in your area to inquire about a complete change. The 100k mile OCI is for normally driven vehicles. You have a tune so I will guess you flogged the car fairly well. In this instance ZF recommends an OCI of approx 60k miles. You're over.

[fdriller9]

Originally Posted by Turkeybaster115

To get the fluid out of the torque converter, you can just do multiple drain and fills, and drive around in between.

That's a huge pain in the ass...

[Turkeybaster115]

Originally Posted by *********

That's a huge pain in the ass...

No its not. Just do one drain and fill, drive around for like a week, and then do a second one.

[chromisdesigns]

Originally Posted by Turkeybaster115

No its not. Just do one drain and fill, drive around for like a week, and then do a second one.

When do you change the pan and filter -- during the second refill?

[Turkeybaster115]

Originally Posted by chromisdesigns

When do you change the pan and filter -- during the second refill?

I haven't even changed mine yet. I'm waiting to go over 120K before i do it. The second drain and fill is just to ensure that all 11 Liters gets changed, even the stuff in the heat exchanger. That's why I drove mine around for like a week, first. After doing quite a few of these, my trans fluid went from burnt black at 50K to crystal clear at 86K, with tons of track days and zero shifting issues.