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noise from auto box at 20 mph

Posted: Mon Oct 22, 2007 7:45 am
by n5loy
Hi Guys ,I got a problem with my 95 2.o ltr auto box .
Strange cause it started soon after i got the car and i have covered 8000 miles! and the problem never gets any worst.
Basically it makes a crunch noise when you reach 20 mph when you first drive off and then everything is fine and the box is super smooth.
when you turn the engine off and restart it will make the crunch again at 20 mph (only once).I presume 20 mph is the change up point on the box.I have taken my 480 to about 4 garages none have been able to solve the problem.Comments like 'they all do that' and ' there's nothing wrong with it' do not help !
Transmission oil has been changed twice.Thinking about having a recon box fitted .
Any Ideas much Appreciated.
Regards Lloyd

Posted: Mon Oct 22, 2007 11:17 am
by Big Brother
Are you sure it’s the gearbox and not the ABS calibrating, it’s a mechanical ‘cough’ which occurs when you are doing around 20, this only happens once until you turn the engine off

autobox noise at 20mph

Posted: Mon Oct 22, 2007 4:42 pm
by n5loy
Hmm thats an interesting theory, how could I tell if its that and is there any need to worry about my ABS ?
The noise comes from the right hand side of the engine compartment as you sit in the car and you can very slightly 'feel' the crunch through the throttle pedal.Sometimes if you accelerate quickly enough through 20 mph it will make no noise at all.
I was reading about Lubegard in the forum ,which i have ordered ,that mentions 'valves sticking' in the transmission is that a possibility.
Would a fault with the auto box only happen once every start up and never get any worse over 8000 miles.
Thanks for your help
regards
lloyd

Posted: Mon Oct 22, 2007 5:10 pm
by robertjary
My 480 auto makes the same noise - had me puzzled till I read the handbook. It's the ABS controller - occurs after each start at about 20 mph.

Posted: Mon Oct 22, 2007 6:05 pm
by Anton_K
Thanks for the info volvo-bigbrother :) been wondering about that myself, what that sound is.. Guess it´s time to refresh my German :wink: handbook is in German..

Posted: Mon Oct 22, 2007 6:15 pm
by Big Brother
Your welcome :)

noise at 20mph

Posted: Tue Oct 23, 2007 7:15 am
by n5loy
Hurray !
I was saving up for a new autobox .
So does that mean the ABS is OK or does it need looking at?
THanks guys

abs vibrating

Posted: Tue Oct 23, 2007 7:41 am
by n5loy
Yep just read it page 3.11 ABS section in hand book .

'At a vehicle speed of approximately 30 km/h (but only immediately after starting the engine) a slight vibrating noise may be heard.this is caused by the diagnostic system of the ABS which automatically completes a test cycle of all ABS functions.'
So my ABS is ok as well , fantastic!
:D Thanks again.

Posted: Tue Oct 23, 2007 5:22 pm
by martinholmesuk
REcord the sound for us and put up on a site or mail me martinholmes @ hotmail.com

I had crunching sound when the drive shaft was moving but when on power there was no sound.

also what happens if you drive off at a few mph and stick it in park? Same sound?

Does it go Whoop on a gearchange

Drive it in 1st and do not change into 2nd until 40mph.

does it make a sound?

auto box noise

Posted: Wed Oct 24, 2007 6:38 am
by n5loy
Hi there,
do not think sound would be loud enough to record easy.
tried putting in 1st and sound still happens again only once and only at 20mph /30kph like it says in the hand book.
I think it's the abs resetting defo.
Apart from this 'cough' The auto box has been super smooth and quiet for the last 8000 miles and cruises super quiet on motorway.
Cheers all. :D

Posted: Wed Oct 24, 2007 7:45 am
by martinholmesuk
It's not a gear change problem thank god. You really don't want to change the box.