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C30 / S40 & V50 '04-'12 / C70 '06-'13 General Forum for the P1-platform C30 / S40 / V50 / C70 models |
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Oscillating RPM When DrivingViews : 3190 Replies : 18Users Viewing This Thread : |
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Nov 5th, 2019, 20:31 | #1 |
Clueless
Last Online: Jun 13th, 2024 15:08
Join Date: Apr 2013
Location: Wrotham
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Oscillating RPM When Driving
Hello everybody,
Two days ago I noticed that the RPM oscillates when driving under light load with my V50. I found a thread on another forum that has a video that shows this issue perfectly although there was no solution/cause posted so I am hoping that one of the many mechanical guru's here can help. It is a 2004 V50 with a 2.4i engine, automatic gearbox and 131k miles. It starts fine, idles fine, seems to drive fine, but this oscillation is worrying me. If I put it into manual (push the stick left) then the oscillation doesn't seem to be present so I am guessing it is something with the gearbox not being able to fully engage a gear or the clutch is slipping, or something... (do automatics have a clutch?) Video: https://youtu.be/IajaS7Nk2bk Forum link: https://www.picoauto.com/support/viewtopic.php?t=16251 I have just had to spend £400 on sorting the front suspension so the last thing I need is another hefty repair bill. :-(
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Current Volvo's: S40 1.8 (55) & V50 2.4i (04) Past Volvo: S40 1.8 ('97/R) & 240 GLE ('76/R) |
Nov 5th, 2019, 22:40 | #2 |
Junior Member
Last Online: May 12th, 2020 17:23
Join Date: Oct 2018
Location: Mancunia
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Gearbox oil is old or out-of-spec. Not uncommon in autos. The only way to fix the symptom is to change the oil to whatever is recommended (or better).
If it's old (i.e. it's done 131k) then the oil & filter will need doing _sooner_ rather than later - they'll likely be debris in the oil which can damage your box. If it's been changed recently (like at 100k) then you may be OK for a while. It's generally not a hard job if you're handy with a spanner. Ask around for a price if you don't fancy it |
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Nov 8th, 2019, 08:54 | #3 |
Master Member
Last Online: Jan 17th, 2023 10:06
Join Date: Aug 2011
Location: Cardiff
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That's the torque converter lockup clutch failing to engage properly. I had the same issue with a ZF6HP automatic gearbox in an S-Type Jaguar. Anything newer than a 4 speed auto uses controlled slip lock-up, and yours isn't controlling the slip properly. Presumably when you put the transmission into "geartronic" manual shift mode it keeps the TC unlocked for faster shifting.
Changing the oil may help, but medium case you may need a new/refurb torque converter. If it's shifting fine otherwise you should get the fluid changed and see if that fixes it, but you should be aware that 130k miles isn't an uncommon mileage for these 5 speed AW boxes to fail at, if they've never had a fluid change.
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2016 XC60 D5 SE Lux Manual 2008 C70 D5 SE Lux Manual 2004 V70 T5 SE Geartronic 2003 C70 T5 GT Manual |
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Nov 9th, 2019, 20:49 | #4 |
Clueless
Last Online: Jun 13th, 2024 15:08
Join Date: Apr 2013
Location: Wrotham
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Update: I ran it with a diagnostics tool connected and once it had warmed up it kept flipping between "Slipping lock up" and "Fix lock up" every now and again on a fairly flat surface at a constant speed. Yes, when it was in 'geartronic' it seemed ok. The gearbox doesn't seem to be noticeably slipping otherwise.
I also looked through the receipts I got with the car. They were all mostly main dealer up until two years ago (it was very well looked after) and there was no mention of the transmission fluid being changed or topped up (this was listed on the dealer check list as 'n/a'). I can therefore assume that it has never been changed. I have been quoted £200 by my local reputable garage to change the transmission oil, of which half the cost is the oil and the rest being labour. I have seen second hand gearboxes on eBay for £500 (condition questionable?), and £1,800 +vat for a new gearbox. This car has been otherwise reliable and apart from £400 for new front shocks hasn't cost me much in maintenance (it did also cost £300 for three new tyres and £250 for a spare key). I only bought it in March this year for £1,800 but what with all this and my last car being destroyed by an engine fire at the start of the year* I am wondering if I am cursed and I should just put it on eBay for £800 and go and get myself a pedal bike... * https://www.kentonline.co.uk/maidsto...r-park-199942/
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Current Volvo's: S40 1.8 (55) & V50 2.4i (04) Past Volvo: S40 1.8 ('97/R) & 240 GLE ('76/R) Last edited by eric19371; Nov 9th, 2019 at 20:56. Reason: additional text and bad spelling |
Nov 9th, 2019, 22:03 | #5 | |
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Last Online: Jan 15th, 2024 15:32
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Location: london
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Quote:
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Nov 9th, 2019, 22:20 | #6 |
Flaccid Member
Last Online: Jun 2nd, 2024 00:14
Join Date: Nov 2016
Location: Norwich
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if you dont cane it you can go a couple years with new fluid
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2001 Volvo S60 T5 SE 2.3 Geartronic (Scrapped) 2007 Volvo S60 T5 SE 2.4 Geartronic (Sold) 2008 Volvo V70 D5 SE Sport Geartronic (Current) |
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oscillating revs, oscillating rpm, varying revs, varying rpm |
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