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Rattle/knocking from gearbox?

Posted: Tue Jun 07, 2011 7:30 am
by PeteE30Tourer
Morning all,

I noticed last week that my 325 cab was making a knocking noise from underneath, possibly from the gearbox when in neutral with the clutch up. Press the clutch down and the noise disappeared.

However, driving it yesterday, I noticed that the knocking was more persistent now no matter what I do with the clutch or gears. It's not very loud and it drives absolutely fine, but at low speeds or when standing, it's noticeable from inside the cab.

Any ideas?

Re: Rattle/knocking from gearbox?

Posted: Tue Jun 07, 2011 7:44 am
by RM2186
Sounds like the clutch thrust bearing is worn to me.

Re: Rattle/knocking from gearbox?

Posted: Tue Jun 07, 2011 7:57 am
by PeteE30Tourer
Cheers - expensive/time-consuming to replace?

Re: Rattle/knocking from gearbox?

Posted: Tue Jun 07, 2011 8:08 am
by RM2186
If it proves to be the thrust bearing, I'd leave it until you plana clutch change, that way, no extra cost :D

Re: Rattle/knocking from gearbox?

Posted: Tue Jun 07, 2011 8:18 am
by PeteE30Tourer
Is it ok to run like that then, or is it likely to break at some point leaving me stranded?

Re: Rattle/knocking from gearbox?

Posted: Tue Jun 07, 2011 8:24 am
by RM2186
I think the noise it will make before it busts will have scared you long beforehand. :)

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 1:00 pm
by PeteE30Tourer
Oh dear - things have got significantly worse. Rattle much louder and apparent whether clutch is up or down, in gear or out. Starts as soon as engine starts. Very noticeable from inside car.

Cant see it being the thrust bearing now.

Any ideas?

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 1:32 pm
by e30-EVN
Thrust bearings can get pretty loud before they go mate, maybey its getting time to fit a new clutch kit :)

Having said that your layshaft could be fooked, I had the same with my old box on the m50, put a new box and clutch kit on my m52 and stuck that in instead and all fine.

Does the box whine in any gear at all??

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 1:34 pm
by PeteE30Tourer
Would a thrust bearing make the same noise regardless of whether the clutch pedal was up or down?

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 3:26 pm
by ed325i
I would think its the layshaft.

Ed

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 4:17 pm
by e30-EVN
Ed, I'd be inclined to agree mate, as per the edit to my post earlier :)
I had the same trouble :(

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 4:20 pm
by PeteE30Tourer
I take this means dropping the gearbox out and stripping it down?

How many hours for a competent mechanic?

Parts cost??

Better to fit second hand gearbox?

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 4:31 pm
by e30-EVN
I would slap a new box in there mate. Would be cheaper than getting someone to strip down and rebuild your one! Tbh with you I got rid of my old m42 box and refitted a new 1 to my m52.

They can be found on here at reasonable enough price 8)

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 4:34 pm
by PeteE30Tourer
Bit of a gamble getting second hand box - could have same problem.

Are recon gearboxes available?

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 4:45 pm
by craigieeb
http://www.chriswarburton.co.uk/parts.htm

If there's none on the website,
drop him a message
:cool:

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 4:55 pm
by e30-EVN
Not if you get the box from a reliable source mate! I had a box off magpie and mine is mint 8)

Re: Rattle/knocking from gearbox?

Posted: Wed Jun 08, 2011 10:16 pm
by PeteE30Tourer
Thanks Craig - gave them a call today and they didn't have any 325 boxes in stock.

I'll head off to the "For Sale" section to see what I can find.