17 replies to this topic

[MikeJE]

I have had quite a bit of work done on my 998 gearbox, most recently fixing the synchro on 3rd gear. It was always quiet running but after the last round of work I notice that in 4th gear there is a definite whine on acceleration which goes when the throttle is lifted but returns on overrun. I am not sure if the noise is there with other gears as the car is a bit noisy. In the 'old days' I would have suspected the differential bearings were wearing, but is this likely with the mini? If so, what is needed to rectify it? The final drive was replaced by Guessworks about 2k miles ago with a 3.1 ratio unit.

 

Very grateful as always for any advice from the forum.

 

With best wishes

 

Mike

[Spider]

I'm sorry to read that you have some on going troubles here.

It could possibly be from the drop gears or the Laygear or the final drive gears making poor mesh from a worn Mainshaft Bearing.

Regardless, the engine needs to come out and likely the gearbox off. Usually, I've found over the years, once one part of the gearbox is worn, be it a bearing, layshaft, final drive, baulk ring etc, then the rest of the gearbox is not far behind. I get that they can be costly to fully overhaul but this is what I'd be suggesting here.

[Lplus]

I have had quite a bit of work done on my 998 gearbox, most recently fixing the synchro on 3rd gear. It was always quiet running but after the last round of work I notice that in 4th gear there is a definite whine on acceleration which goes when the throttle is lifted but returns on overrun. I am not sure if the noise is there with other gears as the car is a bit noisy. In the 'old days' I would have suspected the differential bearings were wearing, but is this likely with the mini? If so, what is needed to rectify it? The final drive was replaced by Guessworks about 2k miles ago with a 3.1 ratio unit.

 

Very grateful as always for any advice from the forum.

 

With best wishes

 

Mike

How long ago was the last lot of work done on the gearbox?  Presumably not the same time as guessworks replaced the diff and after that work by guessworks there was no noise.  Assuming they are different occurrences, I wonder if the idler gear was inserted the opposite way round by the last person to reassemble the engine.  Gears that have happily meshed together in one orientation will have worn in certain ways and turning the idler round will present unworn faces to worn faces, which could cause some whining noises.  Unless the whine is particularly loud, I would personally leave it and see if it gets worse before ripping it all apart again.  Clearly it can't be too bad or you could hear it in all gears.

 

But that's just me who has minis with all sorts of mismatched bits and accepts a bit of whining as normal.

[MikeJE]

 

I have had quite a bit of work done on my 998 gearbox, most recently fixing the synchro on 3rd gear. It was always quiet running but after the last round of work I notice that in 4th gear there is a definite whine on acceleration which goes when the throttle is lifted but returns on overrun. I am not sure if the noise is there with other gears as the car is a bit noisy. In the 'old days' I would have suspected the differential bearings were wearing, but is this likely with the mini? If so, what is needed to rectify it? The final drive was replaced by Guessworks about 2k miles ago with a 3.1 ratio unit.

 

Very grateful as always for any advice from the forum.

 

With best wishes

 

Mike

How long ago was the last lot of work done on the gearbox?  Presumably not the same time as guessworks replaced the diff and after that work by guessworks there was no noise.  Assuming they are different occurrences, I wonder if the idler gear was inserted the opposite way round by the last person to reassemble the engine.  Gears that have happily meshed together in one orientation will have worn in certain ways and turning the idler round will present unworn faces to worn faces, which could cause some whining noises.  Unless the whine is particularly loud, I would personally leave it and see if it gets worse before ripping it all apart again.  Clearly it can't be too bad or you could hear it in all gears.

 

But that's just me who has minis with all sorts of mismatched bits and accepts a bit of whining as normal.

 

The diff was replaced a few years (but only about 1500-2000 miles) ago when the box was overhauled but the noise only started after the more recent work, earlier this year. But that was just to sort out the 3rd gear synchro. Nothing else was touched. I can live with the noise, but it is a bit annoying especially having spent so much on various repairs to it. I suppose I can take the engine out again over winter to see if the idler gear needs to be replaced or have it checked over for the issues mentioned by @spider above.

Many thanks for your response, much appreciated

Best wishes

Mike

Edited by MikeJE, 25 August 2024 - 02:59 PM.

[Lplus]

 

 

I have had quite a bit of work done on my 998 gearbox, most recently fixing the synchro on 3rd gear. It was always quiet running but after the last round of work I notice that in 4th gear there is a definite whine on acceleration which goes when the throttle is lifted but returns on overrun. I am not sure if the noise is there with other gears as the car is a bit noisy. In the 'old days' I would have suspected the differential bearings were wearing, but is this likely with the mini? If so, what is needed to rectify it? The final drive was replaced by Guessworks about 2k miles ago with a 3.1 ratio unit.

 

Very grateful as always for any advice from the forum.

 

With best wishes

 

Mike

How long ago was the last lot of work done on the gearbox?  Presumably not the same time as guessworks replaced the diff and after that work by guessworks there was no noise.  Assuming they are different occurrences, I wonder if the idler gear was inserted the opposite way round by the last person to reassemble the engine.  Gears that have happily meshed together in one orientation will have worn in certain ways and turning the idler round will present unworn faces to worn faces, which could cause some whining noises.  Unless the whine is particularly loud, I would personally leave it and see if it gets worse before ripping it all apart again.  Clearly it can't be too bad or you could hear it in all gears.

 

But that's just me who has minis with all sorts of mismatched bits and accepts a bit of whining as normal.

 

The diff was replaced a few years (but only about 1500-2000 miles) ago when the box was overhauled but the noise only started after the more recent work, earlier this year. But that was just to sort out the 3rd gear synchro. Nothing else was touched. I can live with the noise, but it is a bit annoying especially having spent so much on various repairs to it. I suppose I can take the engine out again over winter to see if the idler gear needs to be replaced or have it checked over for the issues mentioned by @spider above.

Many thanks for your response, much appreciated

Best wishes

Mike

 

Nothing else may have been changed whilst fixing the 3rd gear synchro but most of the geartrain will have been removed and replaced to do the work - as well as the clutch, clutch housing, idler gear, input gear and so on.  Even if you replaced the idler gear it won't match the wear on the primary gear or input gear, so it might still whine.  I suppose you could replace all three gears but the cost is racking up.

 

Might be a winter project if it gets any worse.
 

[Spider]

I'll add here - though it's not likely the issue given the low mileage you've done - that there are many lesser grade needle roller bearings being supplied by most of the parts suppliers for our gearboxes. These have fewer needles in them and are shorter. These have been shown not to last too well.

https://www.theminif...-gear-bearings/

 

https://www.theminif...-quality/page-2

[absx2]

Great information from Spider as usual, getting decent parts is a minefield now and the big suppliers can and will sell you any old junk.

 

Is anyone else shocked that MikeJE has had trouble with his reconditioned box after 1500 -2000 miles !! 

[Spider]

Sorry, I'm only just now picking up that the Gearbox has recently (as far as mileage goes) been overhauled ? 

If so, my bad then, as It sounded like just a few parts had been replaced.

[MikeJE]

Many thanks, everyone, for taking time to respond. I think a winter project beckons, with a close eye on checking replaced parts for quality!

 

Very best wishes

 

Mike

[bpirie1000]

Have to agree quality and sizes vary so much these days. All about getting the hits made and sold ASAP...

[Lplus]

Sorry, I'm only just now picking up that the Gearbox has recently (as far as mileage goes) been overhauled ? 

If so, my bad then, as It sounded like just a few parts had been replaced.

I understood just thrird gear synchro bits had been changed - presumably the rest was inspected during dismantling and nothing else was found that needed replacing.  Maybe i've misunderstood.

 

Or are you talking about Guessworks changing the diff? That wouldn't necessarily involve a full dismantling...

Edited by Lplus, 26 August 2024 - 01:43 PM.

[Spider]

.I understood just thrird gear synchro bits had been changed - presumably the rest was inspected during dismantling and nothing else was found that needed replacing.  Maybe i've misunderstood.

 

That was my initial take on it, but just reading some of the other posts, I am not too sure.
 

[MikeJE]

So sorry, all, that my initial post wasn't clear. The gearbox was subject to an overhaul about 2k miles ago, following which 3rd gear synchro didn't work (it crunched when changing down and sometimes when changing up). So earlier this year someone else fixed the synchro so it now changes up and down without crunching, but since then there has been a whine - apparently only in 4th gear although it may be there in lower gears but is not obvious. I believe the box was checked when the synchro was fixed, with nothing obviously wrong being found. While the whine is irritating it is not overwhelming and I can sort of live with it, but I try to keep my mini in the best condition possible so I would like to try to find out what it is and fix it.

 

From what you knowledgeable folks say I think it may need a gearbox strip (again) to find anything (and everything) that is not 100%.

 

Again, many thanks all for your helpful advice, as always

 

Best wishes

 

Mike

Edited by MikeJE, 29 August 2024 - 07:39 AM.

[Spider]

Thanks for the clarification here.

If I can say, the whine may appear a little annoying - now. Depending on exactly what the issue is, it may not be an issue for a long while going forward, however, often the sound is from gears meshing at the wrong helix angle with each other, which in turn is from a worn bearing or shaft. OK, so while that bearing or shaft is likely U/S and will in time need replacing, with the gear(s) running this way for an extended period will wear through the tooth case hardening, so on top of the shaft or bearing, you could find yourself also up for gear(s) too, which are fairly expensive these days.

If I can suggest here, perhaps have the car examined and test driven by someone who knows Minis, get their opinion.

[MikeJE]

Thanks for the clarification here.

If I can say, the whine may appear a little annoying - now. Depending on exactly what the issue is, it may not be an issue for a long while going forward, however, often the sound is from gears meshing at the wrong helix angle with each other, which in turn is from a worn bearing or shaft. OK, so while that bearing or shaft is likely U/S and will in time need replacing, with the gear(s) running this way for an extended period will wear through the tooth case hardening, so on top of the shaft or bearing, you could find yourself also up for gear(s) too, which are fairly expensive these days.

If I can suggest here, perhaps have the car examined and test driven by someone who knows Minis, get their opinion.

Thanks Spider. I agree. Is there anyone within reasonable driving distance of Sutton (Surrey) who is experienced at this sort of thing and can diagnose the problem by driving the car, please? I will, of course, pay. 

 

Grateful for any suggestions

 

Best wishes

 

Mike