08-09-2017, 06:15 PM | #1 |
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Squeak on cold upshift?
The other day I noticed a squeak when my M240xi (8spd/auto) was upshifting soon after start up and under moderate acceleration to get up to speed on the road. Almost like a belt squeak, but was quick and gone. It did it again today under same cold startup conditions. Seem like it's only 1st to 2nd gear or 2nd to 3rd. After that, it's fine, and after a few minutes, car is warmed up enough and it's silent on shifts again. Obviously, I'll be having it checked it under warranty, but it will be a few days before I can get it in. Any thoughts on what this might be?
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08-09-2017, 08:29 PM | #2 | |
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08-10-2017, 06:35 PM | #3 | ||
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08-10-2017, 09:27 PM | #4 |
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Of course! LOL!
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08-15-2017, 06:36 PM | #5 |
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This happens to mine occassionally as well.
M240i RWD. Also seems to happen only when car is cold. Very brief, sounds almost EXACTLY like tyres losing grip on white painted lines on the road. only a very brief squeak. Like driving on a painted concrete surface, such as a car park! Almost like something is slipping!!!! |
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08-21-2017, 06:37 PM | #7 |
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My work schedule hasn't afforded me time the last two weeks to get it in. I'm hoping things calm down by next week and I can drop it off for a day. It does it everyday for me if I get the revs up and it shifts when cold started. It's quite loud with the windows down.
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08-29-2017, 12:13 AM | #8 |
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I've only driven her about 4 times in the last two weeks (weekends)
and I haven't heard the pip squeak again. Although in saying this, I'm a little paranoid now, and have incorporated an engine start and warm up into my "Getting ready to leave the house" routine. Maybe a cold ZF doesnt like the quick shifts. I've owned a Ford FGX Falcon XR6 Turbo (Aussie Aussie Aussie / Oi Oi Oi) which pairs a 4.0L Straight 6 with big turbo with a 6 speed ZF box, and I've never ever heard anything like the Bimmer noises on cold shifts. |
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09-02-2017, 12:01 PM | #9 |
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Judging from the videos I've seen posted, it's got to be belt slip on harder shifts. Two Lexus ISFs I've test driven would squeak their belts on hard shifts, especially the 1-2. There are videos showing this as well. The ISF has a super quick shifting automatic as well and the squeak is just something the ISF owners have learned to live with as there's really no fix and it's really not causing harm.
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09-02-2017, 01:10 PM | #10 | |
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08-01-2018, 08:03 PM | #12 |
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I still get this, and I'm more and more and more convinced its just COLD soft compound tyres...
it plays trickery on you, because if YOU shift using the paddles itll shift harder even when cold and force the tyres to grab at the pavement and beacuse they're cold hard tyres, they slip and squeak a bit. I could be wrong though... |
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08-03-2018, 01:29 PM | #13 | |
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06-29-2021, 09:58 AM | #14 |
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Found this old post as my m240 is doing this. I thought it was the BOV releasing during a shift, but now that I'm searching the B58 doesnt have a BOV? I think I just read the wastegate opens to act as a BOV (surge release)? Maybe thats what I'm hearing.
If I run in Manual and flick the throttle closed, it doesnt seem to do it. It ONLY does it while shifting with throttle open. Which makes me think its not throttle/pressure issue and has nothing to do with throttle and more with shifting. I didnt think of belts (as from this post) but that could be possible. There's no way its tires chirping as I'm AWD and it happens under part throttle. |
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07-23-2021, 10:08 AM | #15 |
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Now that all I do is drive around listening for the squeek, its not on a SHIFT but on a slight throttle change (which also happens during a shift). No squeek on WOT (or I cant hear it). This makes me go back to thinking its the wastegate making the noise. It only happens on part throttle open or close and with very small RPM change so I dont think its a belt. Unless the tricky alternator that disengages on throttle could be a thing. But I found another thread saying a failing/stuck exhaust actuator can cause the second exhaust to squeek as it opens and closed. Going to unplug mine over the weekend and see what happens.
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10-03-2021, 02:40 PM | #17 |
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I have the same annoying pip squeak on Sport Mode on my 240xi. Mine I can only hear on deceleration while driving on small little local streets. I only noticed mine after I enabled Burble on the Fly with my tune. I had a feeling it might be exhaust flap or BOV. How did you test for the exhaust flap?
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10-13-2021, 12:17 PM | #18 |
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You can reach under the back bumper without jacking the car and unplug it. Once you do it once and know where to get your fingers to press on the plug to unplug it, its easy. (first time not so easy) Doesnt matter if exhaust is hot, its temp isolated so no burnt fingers.
Put car in sport mode while running and unplug=flap always open Put car in comfort while running and unplug=flap always closed My noise didnt exist while unplugged. Now I know: the flap is opening and closing in both comfort (hit the gas too hard, it will open for power) and also in sport (does it close at low rpm for backpressure while not under boost? Dunno WHY but I can hear that it doesclose for some reason) A blob of synthetic grease on the bearing outside of exhaust quieted mine (on exhaust pipe, not on flap motor) |
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10-17-2021, 10:11 AM | #19 | |
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