Gearbox dragging during downshift

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Posts: 6
Joined: 04 Apr 2022, 09:40

Gearbox dragging during downshift

Post by Thommm »

Hi y'all,

I've just finished the install of an 8HP70 in my E28 with an M62 but I'm facing an issue during downshifts. The TCU has learned the upshifts pretty well and it's decently smooth, but it's dragging a lot when I downshift. The downshifts from 3-2 and 2-1 take very long (down time set to 1) and when downshifting to 2 or 1st without throttle it usually comes to a standstill, before completing the shift and starting to roll again.

I've attached a log and my bin file, anyone with an idea what I could do to have the TCU adapt? It feels like it needs to release the clutch packs from the gear it's in earlier than it is, there's too much overlap.

BMW E28 M62B44 turbo 8HP70 SW10_66NoCan.bin
(16 KiB) Downloaded 22 times
dragging gear during downshift 29092022.xdl
(90.1 KiB) Downloaded 20 times
Posts: 61
Joined: 18 Aug 2021, 21:00

Re: Gearbox dragging during downshift

Post by Jar »

have you updated the TCU to the latest version? remember that the software update itself does not make any corrections. The reason for this is to maintain compatibility between versions.

After updating the software, you need to use a new settings file (.BIN) which include new functions. In order for the pro tuner to see the new settings, you must also load new files (.XDF & .ADX)
Posts: 3
Joined: 26 Nov 2021, 23:13

Re: Gearbox dragging during downshift

Post by Racekatt »


I am also having the same problem with dragging.
Some says my clutches are worn, but my gearbox only have 19.000km on it, so i find that a bit strange.
Posts: 7
Joined: 06 Jan 2022, 22:14

Re: Gearbox dragging during downshift

Post by mppetrov »

Same here. 110k km gearbox.

I noticed when i shift manually, sometimes i manage to do good enough ( way more smoother than when automatic). Still not like oem car, but ok.

Is there a way to copy the manual downshift parameters to automatic mode? I guess yes, but dont know what to log for and which tables needs to be edited?
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