(G) Gearbox Problems

A couple of days ago, my gearbox started making a horrible growling sound when I take off in first gear it does it about 1 in 3 times, its fine in all the other gears though. any thoughts on what this might be?


Cheers,

Matt

my friend's uno 45 has the same problem and we figured out that it was his engine mount in the front... the bushing is shot and it's allowing the engine to move too much under load... it's even worse in reverse...

check to see if you're engine mounts are good... if they are, then i'm thinkin of another kind of noise...

hope this helps a little at least

peace

I think it's most likely to be the input shaft bearing, since you have described the noise as a 'growling' noise. When bearings fail, it's usually because the hard surface of the ball race breaks up. This makes a roaring or rumbling noise as the balls run over it, just as you expect car tyres to make a roar or a rumble travelling over rough NZ road surfaces. Train wheels don't tend to make a roar or a rumble. Oops, sorry, getting a little carried away in thought...

The next result is that the now-exposed softer material of the bearing wears out. The shaft (carrying the gears) begins to slop around with the excess clearance. Then the gears themselves will start to wear in odd ways. This means that even when the bearings are later replaced, the gears may whine unexpectedly. However there are often whines inherent in FWD transmissions (Minis are particularly bad!) and supposedly low gears in the Uno have detectable whine according to contemporary road tests (i.e. when the Uno was brand-new!)

The input shaft bearing is the 'first' bearing of the gearbox, at the end nearest the clutch. Therefore the loading on it is greatest (most vibrations) when first gear is engaged (the gears are arranged in pairs one after the other, with fifth gear in the 'extension' housing).

Also the vibrations generated by gears and the engine will be strongest when first moving off.

Another friend of mine (who may be reading this, hello James...) has an Uno with a gearbox that sounds like a bus (roaring noise). I think this is the input shaft bearing as well because it's most noticeable in low gears. I noticed also, when we hooked on a trailer with another Uno on it, that the gearbox became a lot more noisy when moving off under a heavy load.

Well that Uno is still going after roaring for two years, so yours may continue for a while. But my suggestion would be to remove the 'box ASAP (i.e. when you have alternative transport for a week or two) and have the bearings checked by someone who knows what they're looking at ;-) I think we both know someone, and it isn't me...

-Alex