My gearbox is making a very strange noise, help please!!!

[Mike Buley]

I think I have broken it.. :roll:
Everything is fine up to 30mph. Then...it makes a noise similar to ....this is going to sound stupid but.....if you had a raleigh chopper when you were a child, you used to attach a playing card to the rear wheel so that it made a noise against the spokes sort of a brrrrrrrrrr. The faster you went the faster the noise.
This is what it sounds like, it still changes gear (mind you I havnt gone above 30) Stops, starts, engages etc.
I am cacking myself.
Help please folks,
Mike.

 

[Mike Buley]

maybe I should change that signature now......

 

[jaques2k]

I have had the same noise from my gearbox (380SE -85), it´s noticable, and appears only at a certain speed. If you speed up or down from that the noise disappears. Though, I have a manual gearbox, and the leather "coating" is removed around the shifter, so it´s much more noticable then. But I hadn´t got time to investigate it before my car went into service and a complete motor renewal. Has been on the workshop for 6 weeks now... hopefully I´ll get it this week (including a nice bill . I don´t know if the sound is still there when I get it back. The mechanics said that the "rattle" could be from a loose engine mount, because it was a bolt near the engine mount that was loose and ratteling. But I don´t think so, because it really sounds as it would come from underneath the car, near the gearbox. Maybe it´s something that´s laying on to the driveshaft, I don´t know... Let´s see what comes up in the forum Good luck!

 

[longdog5]

Hi,
If this is an autobox then I would change the filter, a partly blocked filter causes the pump to pull very high suction levels (very strange sounds) and can mimic all sorts of things, usualy screaming or chattering noises.
Whip the pan off the box and look for debris in the pan , if you find it changing the filter may only be a short term fix. Change the filter anyway and keep your fingers crossed. The filter is not expensive and the job takes only 2 hours tops. If I'm wrong the box will still benefit from the new filter.
LD5

 

[Mike Buley]

Thanks for the replies chaps.......
I really really do NOT understand this problem. I took the car for a spin to have a really good listen, nothing. Not a dicky bird, it changed up and down, did everything perfectly. This noise was previously so loud, it made people look over their shoulders from about 100 yds.

Which to me, indicates it cant be mechanical, as a broken part doesnt fix itself.

Could it be the Cat(alytic converter) or middle bit of the exhaust. I know it sounds silly, but it isnt blowing.

Hmmmmmmmmmm.....

 

[altreed]

Hi,

I had a similar sound on my immaculate and well maintained manual 190e. I went out for the day and drove to Bath, 60 miles away, on a lovely sunny day. We were travelling on a good road at about 60+ mph. All of a suddent a loud clattering. I slowed down rapidly and it stopped!

I drove along gently and the sound had gone. I sped up and it came back. Alarmed by this I took it to the MB agent at Bath to investigate.

The techie drove the car and then put it on the ramps. He went straight to the prop shaft. There is a spline drive out of the gearbox that allows a slight variation in the length of the propshaft in normal use. This has a rubber sleeve over it to protect it from road rubbish getting into the slpines. My car was 10 years old and the rubber sleeve had perished such that a 'flap' had made itself so that it functioned exactly as you describe on a 'chopper', it hit the aluminium exhaust cowling protecting the chassis from heat from the exhaust. The nice MB tech didn't charge for his time, so I gave him some beer money.

The part cost about £4 but fitting was more expensive. I had a local privateer to do the repair.

I hope this makes sense and helps you .

 

[Mike Buley]

That sounds about right, thanks, I will investigate that theory!! :lol:

 

[jaques2k]

altreeed, I was figuring the same thing, just didn´t figure out what the prop shaft was in english (I´m from Finland, you know. I will check that out as soon as possible! It´s a sound that´s hardly noticable, but sounds just like it vas a small rubber piece that slaps to something from the prop shaft... Thanks!

 

[Mike Buley]

Jacques,
That was exactly the problem, I have replaced the propshaft and various rubbers, the car is perfect now.
Thank you very much to all helpers!
Mike.