Series 3 Gearbox possible bad bearing noise

I have recently noticed a noise from the gearbox which sounds like it could be a bad bearing. It's not a rattle, but an underlying metallic whirring noise. It is present in all gears, but more so as you move further up the box. I think it can also be felt slightly in the gearstick.

When I rebuilt the vehicle I will admit that I had the box done on the cheap.

It was a case of them disassembling it, checking for broken teeth and other wear, reassemble, replace seals etc.

I was advised that the cheap way of doing it would be to re-use the original SKF bearings if they still felt smooth. This was compared to replacing with Chinese no-name parts.

The box used to jump out of third gear, which it doesn't do anymore, so some internal work must have been done.

Based on the description I have given, which one would be the first to check?

I have been advised to place both back wheels on axle stands, run the box at low speed and listen with a screwdriver to my ear at various points. This will give more of an idea of where the bearing is.

Thanks for any replies.

If present in all gears then it's probably the main shaft. About the only thing you can do is drain the oil and check for anything unwelcome. Then make sure main shaft nut is tight and there's no movement.
Failing that, it's probably spanner time.

Mainshaft nut tool here if required.

Layshaft also turns in all gears just not loaded in fourth gear.
Which version of the gearbox do you have? ie A B C or D.

Webley1991 said:

I have recently noticed a noise from the gearbox which sounds like it could be a bad bearing. It's not a rattle, but an underlying metallic whirring noise. It is present in all gears, but more so as you move further up the box. I think it can also be felt slightly in the gearstick.

When I rebuilt the vehicle I will admit that I had the box done on the cheap.

It was a case of them disassembling it, checking for broken teeth and other wear, reassemble, replace seals etc.

I was advised that the cheap way of doing it would be to re-use the original SKF bearings if they still felt smooth. This was compared to replacing with Chinese no-name parts.

The box used to jump out of third gear, which it doesn't do anymore, so some internal work must have been done.

Based on the description I have given, which one would be the first to check?

I have been advised to place both back wheels on axle stands, run the box at low speed and listen with a screwdriver to my ear at various points. This will give more of an idea of where the bearing is.

Thanks for any replies.

Click to expand...

youd need to strip it and check ,if it was quieter in 4th youd look at lay shaft brgs, but it could be main shaft or t/box, evenn done expensive it could still need further work ,its just the way it is with small selling parts

Thanks for the replies.

Blackburn: I will not be able to get to the vehicle for the next few days to confirm, but I believe it is a B suffix.

It makes me wonder if it isn't best to gamble on it and live with it hoping it doesn't fail completely. If it's box out and strip down either way, that's a good few weekends lost straight away. It will also most likely hit me in the wallet either way as well. We all know that you can simply look at a series and watch money circling the drain.

Check the reverse stop is set up correctly on top rear of gear box suffix B still uses it I beleive.
Try putting your toe under the clutch pedal and lift the pedal to see if that has any effect , thinking clutch release bearing in constant contact
If latter check your clutch pedal return spring doing it's job also check clutch master cylinder free play.

Thanks for the reply. I had a look today and it's definitely a suffix B. When I said "all gears" I should have made it clear it was all forwards gears.

I put the rear axle on stands so the wheels could rotate freely and ran the box in different gears. I wasn't able to get the box to make the noise like this.

What I did notice is when the handbrake drum was spinning, it was seemed to be pushing backwards in the direction of the red arrow and rattling a bit. Maybe the nut behind the rear propshaft drive flange has come loose.

Handbrake return spring appears to be missing in that pic.
Tighten the output shaft up should be 80ft/lb torque from memory. Once tightened turn the out put shaft with high low lever in nuetral to make sure the bearings are not jammed , if it is you will need to adjust the shims behind the speedo housing.
With that nut loose the bearings will not have the right preload and I would expect your speedometer needle to be eratic.

I finally got round to having another look at this recently. The vehicle has spent most of the last 6 months in a garage.

The nut under the drive flange was tight, but there was still some movement of the shaft in the fordwards/back direction. The manual reads that this shaft should have zero end float, and there seems to be a couple of mm in this case.

The next step looks to be the speedo drive housing shims.

Webley1991 said:

I finally got round to having another look at this recently. The vehicle has spent most of the last 6 months in a garage.

The nut under the drive flange was tight, but there was still some movement of the shaft in the fordwards/back direction. The manual reads that this shaft should have zero end float, and there seems to be a couple of mm in this case.

The next step looks to be the speedo drive housing shims.

Click to expand...

that would suggest a bearing failing, the shafts supported by 2 taper bearings hence the zero endfloat and a slight preoad

Thanks for the reply.

From what I can tell in the book, the rear output shaft bearing is held in place by the speedometer drive housing as it described adjusting the shims to set the preload. From what I described, could the preload be set too loose?

I'm sure I can also hear a slight whine when the gearbox is running, could this also be connected to the same bearing?

Yes but it also could be the circlip that holds fron output shaft bearing in place has failed.
Did you rebuild the transfer box when you did the gearbox

I didn't do the box myself. I had it done (admittedly cheaply) by a place that claimed they would re-use the original bearings if there wasn't any play in them. For all I know they could have re-fitted the transfer box without doing anything to it.

They claimed they would sooner re-use the originals if not worn out, as the ones available today would be lower quality.

They must have done something with the main gearbox as it used to jump out of gear, but doesn't anymore.

Thinking about it, could I see if the circlip is still there by removing the transfer box inspection cover above the output shaft?

Webley1991 said:

I didn't do the box myself. I had it done (admittedly cheaply) by a place that claimed they would re-use the original bearings if there wasn't any play in them. For all I know they could have re-fitted the transfer box without doing anything to it.

They claimed they would sooner re-use the originals if not worn out, as the ones available today would be lower quality.

They must have done something with the main gearbox as it used to jump out of gear, but doesn't anymore.

Click to expand...

they are correct on that

Webley1991 said:

Thanks for the reply.

From what I can tell in the book, the rear output shaft bearing is held in place by the speedometer drive housing as it described adjusting the shims to set the preload. From what I described, could the preload be set too loose?

I'm sure I can also hear a slight whine when the gearbox is running, could this also be connected to the same bearing?

Click to expand...

it could ,but often a worn bearing causes this play,it could but so could other things like bearings and gear teeth

Take some shims out from speedo housing if play goes away circlip is ok , if the play comes straight back it is shot.
How much movement do you have on handbrake drum ?
Did your speedometer behave eractic before you had the current issue?

I took the speedo drive housing and worm gear off today and had a look at the bearing behind it. There was probably a couple of mm movement in the shaft from front to back.

I tapped the outer bearing race forward a few times with a brass rod and the play is now gone.

I am planning to re-set the pre-load and shims tomorrow.

I also took the top inspection plate off and could just see that the circlip was still on. As far as I know, it is possible for these to break and drop into the bottom of the box.

I did notice very fine metallic particles in the gearbox oil after I drained it. From what I understand, this is normal for any gearbox, and should be fine as long as there aren't any big shards of metal or worse broken teeth.

Should the shims have any kind of sealant on them? The manual doesn't say they should, but what's to stop oil from seeping out between them?