[ozz53]

Hi, ive just removed the gearbox to replace the clutch release / thrust bearing and have now found that the noise is in the gearbox. I assumed it was the release bearing due to the noise going away when the clutch was engaged / pushed in. when the main shaft at the front of the box is spun i can here the noise, Im not to sure weather or not to tackle a gearbox bearing job. I am fairly capable on the spanners but not sure if this should be sent to a gearbox shop. How hard are these boxes to change bearings on?

Cheers Ozz

[ozz53]

Is it worth getting another box or even think about pushing the conversion to the 1.6 ltr up my wish list?

[tonyevans]

If it is just the bearing/s that need doing it is not hard at all - Just follow the FSM.

[want33s]

Noise with foot off clutch and no noise with foot on clutch tells me it is the gearbox input shaft bearing not the throwout bearing.

You won't find an easier gearbox to rebuild than a Sierra/Jimny unit.
Download the rebuild instructions and go for it.

[johnmath]

Just for your info, I had noise when foot is off clutch in neutral, no noise when clutch depressed. I had the gearbox rebuilt by Rowell & Searle in Adelaide. My wallet is much thinner now now, but I still have noise. They say it is just gear noise.

[want33s]

johnmath wrote:

Just for your info, I had noise when foot is off clutch in neutral, no noise when clutch depressed. I had the gearbox rebuilt by Rowell & Searle in Adelaide. My wallet is much thinner now now, but I still have noise. They say it is just gear noise.

They are full of shit.
When in neutral with foot off clutch the ONLY part of the gearbox moving is the input shaft. The shaft itself cannot make any noise but the bearing can and does. It isn't necessarily terminal though, my GQ has made noise for the last 75,000km.

[ozz53]

Put a bearing kit through the box today. fairly easy my mate and i did it in a couple of hours, after we put it all back together and while hi fives were going around i spotted a shaft cir clip of the bench but luckily we referred to parts break down and had the clip in its rightful place with in half an hour.
The noise in this one was driving me crazy it was louder than the motor so it had to be done. Ill let ya's know if there is still a noise there after its back in, I would be surprised if there was as ive changed all bearings and shafts all seem good.

cheers

[fordem]

want33s wrote:

When in neutral with foot off clutch the ONLY part of the gearbox moving is the input shaft.

You might want to re-check that - as far as I know this is a three shaft gearbox - input, lay shaft (aka countershaft) & output shaft (aka main shaft) - the lay shaft has a gear in mesh with one on the input shaft so it rotates when ever the input shaft does - the lay shaft has one gear for each "speed" in the gearbox on it (except fourth which is a 1:1 direct drive, so no gears are used) so when the lay shaft rotates, those gears rotate and the meshing partner on the output shaft is also rotating - in fact the only thing not rotating is the selector hubs, the output shaft and reverse gear.

In neutral, you have more rotating than not.

johnmath wrote:

Just for your info, I had noise when foot is off clutch in neutral, no noise when clutch depressed. I had the gearbox rebuilt by Rowell & Searle in Adelaide. My wallet is much thinner now now, but I still have noise. They say it is just gear noise.

Like want33's says - they're full of shit - a rebuilt gearbox should be as quiet as a new one - and if you have noise with the gearbox in neutral, chances are it's a defective bearing - what I suspect may have happened is that the four main support bearings were replaced, but, the gears on the output shaft ride on needle bearings - one of those bearings and/or the shaft itself is defective and has not been replaced.

Defective helical cut gears will rarely make noise unless under some sort of load

[johnmath]

FWIW Rowell and Searle are the most reputable transmission specialist in Adelaide and I was shown all of the replaced bearings and needle rollers.

I understand that countershaft in a Sierra gearbox rotates whenever the clutch is engaged. Gear noise can occur if the cogs have not worn in together, such as when the countershaft has been replaced. They think that my gearbox is a "bitser" made up from two different boxes, and that is why it is noisy.

The gear noise has gradually got quieter over the years, presumably as the gears have lapped into each other through use. If it was the bearing problem, the noise would have got louder through use, not quieter.