First of all, hello, as I'm kind of new here!
I was wondering if anyone is able to diagnose the following problem, as I am a complete novice...
I have a 1990 320i and it's lovely, but when I start hitting the 30mph mark (as most people frequently do!) it makes a fairly loud humming sound, kind of like I have a tumble drier in the boot. I'm fairly sure this isn't a normal sound ha.
The sound is separate to that of the engine and the exhaust, so I'm pretty sure it is nothing to do with either of them.
I have a feeling it is something to do with the rear axles, maybe something to do with the bushes?
Anyone had any similar experiences/anyone able to guess at what it might be? Help!
Humming Sound, rear axle?
Moderator: martauto
-
Elecblondie
- E30 Zone Regular
- Posts: 782
- Joined: Wed Jul 09, 2008 11:00 pm
- Location: Southampton
Yeah I had that, about 20 miles after I first heard it the diff gave up and a post mortem showed that the cross pin had fractured into three pieces and a bit got lodged between the pinion and crown wheel, made a pretty mess of the pinion. If you are driving it be prepared to suddenly lose drive, mine hiccuped a few times before dying, presumably as the end of the cross pin pinged around the case. Not saying it's definitely the diff but it sounds likely to me too.
-
zaust
- Zone day release
- Posts: 13007
- Joined: Sun Jan 09, 2005 11:00 pm
- Location: Somewhere in Hertfordshire , or press Ctrl + W
Take a short drive with the bottom of the back seat rasied or taken out. If the rumble comes form the middle it's the diff, if it come's from one side or the other then it's bearing's. Unless you have an animal rapped roun your drive shaft.
M30 Tech 1 Touring on gas.
High mileage diffs can make all sorts of funny noises in my experience. Someone on here once said just keep running until noise gets too bad - but i'd not heard of exploding diff before! My diff was making a big humming noise like yours and also a jangling metal to metal sound like a bag of old forks. Got a low mileage relpaement from FAB Recycling, Cinderford for £150. Fitting extra of course unless DIY - must be instructions on here somewhere!
It is fairley low mileage. Going to take it to a garage this week, because of what zaust has said, I think it maybe the bearings. I can't remember hitting any animals recently! The noise isn't too bad, just sounds like I'm driving a bi-plane or something. Was going to see if I could pick up a low mileage one off ebay. Are they quite universal in between models, or could I stick one off an old 318 etc?
Thats the ticket.zaust wrote:Take a short drive with the bottom of the back seat rasied or taken out. If the rumble comes form the middle it's the diff, if it come's from one side or the other then it's bearing's. Unless you have an animal rapped roun your drive shaft.
Diff tends to wine when they are on the way out, my money is on a wheel bearing.......
-
Elecblondie
- E30 Zone Regular
- Posts: 782
- Joined: Wed Jul 09, 2008 11:00 pm
- Location: Southampton
Even if it is a diff it's not necessarily expensive if you do it yourself, not a hard job. Nip down a scrappie pick one up for around £50, then simply unbolt the old one and bolt in the new one, you'll need some thread lock, the appropriate socket for the drive shafts ( I think it's an e12 femal torx) and a regular socket set. I'd prefer to do the diff over a wheel bearing anyday personally but either way if you can spare the time to do it yourself don't worry too much about the cost. First thing to do is to lift up the back wheels and feel for play or roughness in the wheel bearings yourself. As for model differences they do have different ratios and autos are much shorter, if you pick one up from a 6 pot you'll need to adjust the length of the prop; probably easier to stick with the 4 pot. I'm sure google will tell you all the ratios.
