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S3 transmission noise


jessejazza
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I am trying to identify the cause of transmission/axle noise. When in 2WD I find she is noisy. Checked oil levels in the gearbox, changeover box, front and rear axles, wheel bearings front and rear. With a landy one should use 4WD I gather at least once a month just to get the oil round (standard hubs not free wheeling) - and I find in 4WD she is beautifully quiet by comparison. It seems one can only use 4WD at low speeds due to the gearing.

Just be grateful for suggestions for investigation as I am relatively new to a LR. If anything in 4WD she should be noisy as there are two diffs in use but it is with 2WD that I get noise.

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24 minutes ago, jessejazza said:

...With a landy one should use 4WD I gather at least once a month just to get the oil round (standard hubs not free wheeling) - and I find in 4WD she is beautifully quiet by comparison. It seems one can only use 4WD at low speeds due to the gearing...

All the same bits rotate in 2WD and 4WD, the only difference is that in 4WD the front & rear axles are connected together, so with standard hubs I see no point in engaging 4WD once a month to splash oil around, it would ensure that the gear linkages &c don't seize up due to lack of use though.  If you have freewheeling hubs it wouldn't do any harm to engage them occasionally to splash the oil about a bit.

If you run in 4WD on tarmac the transmission will wind up due to the very slight difference in speed between the front & rear propshafts.  This winding up will eventually cause transmission damage, but before it does all the backlash in the gears will be taken up, making the transmission quieter.

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Rog is bang on the money - the oil splashing thing is only if you have free-wheeling hubs.

You could always try removing the rear propshaft & driving in 4x4 high to see if it's any different in front-wheel-drive... just remember to put the prop bolts back on to hold the handbrake drum on, and put it in 4x4 before you start or you'll have no handbrake!

You don't mention checking the propshafts, the UJ's can wear and make noise although usually more clunky than anything.

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10 hours ago, rtbarton said:

All the same bits rotate in 2WD and 4WD, the only difference is that in 4WD the front & rear axles are connected together, so with standard hubs I see no point in engaging 4WD once a month to splash oil around, it would ensure that the gear linkages &c don't seize up due to lack of use though.  If you have freewheeling hubs it wouldn't do any harm to engage them occasionally to splash the oil about a bit.

If you run in 4WD on tarmac the transmission will wind up due to the very slight difference in speed between the front & rear propshafts.  This winding up will eventually cause transmission damage, but before it does all the backlash in the gears will be taken up, making the transmission quieter.

Many thanks for your reply.

I drove her a short distance to the corner shop last evening in 4WD. This afternoon I had to do my main shop (about a 12 mile round trip) and put her into 2WD for the trip. Much quieter going there but on the way back she started to get noisy again. So if I have backlash due to wear in the crown and pinion presumably due to previous owners not checking oil level? I wondered if the bearing had gone in the n/s swivel joint. Checked the propshafts for wear and they seem ok.

Edited by jessejazza
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The thing is, there's so many gears in the drive train small bits of backlash all add up.  Another good source of wear is the splines on the half-shafts and the drive flanges they fit into.

If you wind the transmission up and then release the 4WD lever you don't necessarily actually drop back into 2WD, this is because the 4WD drive dog binds due to the tension in the transmission.  This could account for the quieter outward journey to the shops, the 4WD dog will have released itself along the way.

I once drove about 10 miles on tarmac in 4WD, I could hardly steer when I got to my destination.  The only way I could free it up was to jack one rear wheel up with the handbrake off.

NB - if you do jack a rear wheel up the handbrake becomes ineffective, so chock the other wheels or engage 2WD.

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2 hours ago, jessejazza said:

So if I have backlash due to wear in the crown and pinion presumably due to previous owners not checking oil level?

You're jumping to conclusions - why do you suspect wear in certain items rather than others? Can you isolate the noise at all - to one end of the vehicle or one corner? Does it change if you dip the clutch? Does it change with engine RPM or road speed?

Don't jump to conclusions or you end up doing a lot of work for no gain.

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Check the bearings that support the drive shafts - bush in stub axle and a bearing in the back of the swivel housing . Remove the front prop and take it for a run - while it's off check the uj's and sliding joint action and alignment.

cheers

Steve b

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Just re-reading the first post here, you mention the gearing is too low in 4WD -well, not true, you can run in 4WD high range, which is the same ratio as 2WD, so top speed won't be affected.

To summarise the red and yellow knobs.....

 

- Yellow, push this down to go into 4WD. With the red level forward, you are in high ratio.

-  Red, pull back and the transmission drops into low ratio, and the yellow knob springs up, you are still in low ratio, and 4WD is always engaged in low ratio.

If, as you say, it gets noisy in 2WD/high ratio *ONLY*, then it is possible your transfer case has a problem.

However, if you ran it in low ratio 4WD the likelihood of heat build up in order to create the noise is much less, so quite possible the problem is somewhere else. If you run 4WD high ratio and it still gets noisy, then it could literally be anywhere.

Take a mate with you for a drive, and see if they can hear where it is coming from, and once hot play around with the levers to try and work out what's going on.

 

 

 

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As said above, 2wd and 4 high use the same gears.  The only difference inside the transfer box is the forward output shaft dog clutch inside the forward housing.  It could be in the wrong position in 2wd with the dog just clipping the shaft spline ends, so the mechanism would need stripping to look for worn or damaged linkage parts.

The other possibility is that the rear transmission, most likely the prop shaft, has some worn parts but when in 4wd, the front axle is taking enough of the load to relieve the rear end.  You mentioned the rear prop seemed alright, but did you remove it to check the UJs?  It can’t be checked while fitted - you might be confident there is no play, but you can’t detect binding unless you remove it to rotate all the yolks freely.  
 

Far less likely is a worn front diff or prop flailing a little when under minimal load, but settling against the bearings when loaded.

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How old is the vehicle?  Does it have an early transfer box?

{Early (pre about 1963) suffer from wear of the transfer box intermediate gear shaft and roller bearings.  Its relatively easy to cure - the box doesn't have to come out - problem is that the bearings are virtually unobtainable although the shaft was available.  If it wears the thing tends to howl when driven - the noise rising with vehicle speed.  The noise will seem to be coming from the centre seat.  Land Rover cured the problem by massively increasing the size of most of the shaft and the roller bearings - which unusually for Rover - worked.  Bits for the later box are relatively cheap.  You can't fit later parts to an earlier box.}

Using low ratio means that the gear at the back of the intermediate shaft is used as well as the front one.  2WD uses the front gear only.

 

Edited by secondjeremy
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6 hours ago, secondjeremy said:

How old is the vehicle?  Does it have an early transfer box?

{Early (pre about 1963) suffer from wear of the transfer box intermediate gear shaft and roller bearings.  Its relatively easy to cure - the box doesn't have to come out - problem is that the bearings are virtually unobtainable although the shaft was available.  If it wears the thing tends to howl when driven - the noise rising with vehicle speed.  The noise will seem to be coming from the centre seat.  Land Rover cured the problem by massively increasing the size of most of the shaft and the roller bearings - which unusually for Rover - worked.  Bits for the later box are relatively cheap.  You can't fit later parts to an earlier box.}

Using low ratio means that the gear at the back of the intermediate shaft is used as well as the front one.  2WD uses the front gear only.

 

1971 S3 SWB. Not sure of the technicalities. I'll have to investigate on Mon or Tue which are my days off. I don't know any LR folk in the area as I haven't been in Lincs that long. Many thanks for your posts - I'm a HGV driver so I do long days.

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'71 should have an all-synchro box with the later transfer box.  The number will be on the top front of the transfer box arm and there should not be any number on the gearbox itself - which means that you can dismantle the gearbox and find its a different model to what you think it is!  (There are 4 types of S3 main box - identified by suffix letters - A - D)

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  • 3 weeks later...
On 2/26/2020 at 9:07 AM, steve b said:

Check the bearings that support the drive shafts - bush in stub axle and a bearing in the back of the swivel housing . Remove the front prop and take it for a run - while it's off check the uj's and sliding joint action and alignment.

cheers

Steve b

Got the prop off and found there was slight wear in a UJ which may be enough to be the main trouble. She was much quieter I must say but as I have now realised a LR will always be a bit noisy compared with other motors as there is no insulation. To some extent as she's my only motor to get to work in I am worrying  a bit. Many thanks for the replies and suggestions.

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I really don’t think you have a gearbox problem, as it’d be the same in 4wd, and that is the hardest thing to fix, so you can relax a little.  It’s not ideal to drive these on the front axle only, but is ok if you’re gentle.  That’ll give you time to fix the problem without laying it up.  
 

It’s surprising how much noise a bad UJ makes.  Frankly, I’d recommend replacing both as they’re probably equally old and similarly maintained or neglected and the second one will go sooner or later.  Be sure to fit decent quality replacements with grease nipples and grease them every 6000 miles (less if wading or using in harsh conditions).  Check the diff pinion for radial or longitudinal play - it should have some rotational play, but noting lateral or longitudinal.  Take the hand brake drum off (park on level ground, engage 4wd and 1st, and use wheel chocks!) and check the transfer box output flange for similar radial or longitudinal play - there should be none.

Then reassemble and test.  Hopefully it’s just the UJs, but quickly checking the diff and transfer pinions will save removing the prop again for a check if it’s still noisy.

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If it is the shaft it may be worth fitting new ones - by the time you've bought the UJ's, got the thing apart, found the splined joint isn't reallly as good as you'd like, re-assembled it and fitted it new hardy Spicer shafts complete don't seem that bad. (eg)

 

https://www.lrdirect.com/STC121-Propshaft-Front-Swb/?keep_https=yes

 

https://www.lrdirect.com/FRC4907-Propshaft-Rear-Swb/?keep_https=yes

https://www.paddockspares.com/parts-and-accessories/land-rover-series-2-and-3/propshaft.html

 

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Many thanks for your help. Haven't looked at lrdirect - very useful they list the different makes of parts (and prices) they stock. I'll leave the front propshaft off for the moment. Just been looking at the rear this afternoon and  wonder if the spline is rusted up which means that there is no lateral movement... I'll jack it up and explore.

Discovered another problem which I'll put in another post.

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  • 3 months later...

The calamity has happened - last night suddenly all drive went. It can be difficult to determine where the noise is coming from - likely the gearbox or transfer box. I was very grateful for your comments; it was not the rear axle which I suspected as the grating noise would disappear - perhaps the bearings lacking oil until one has done a few hundred yards and then no noise. Yet noise would appear when one went round a smallish roundabout.

I have been looking at the manual to try to deduce the problem - someone mentioned likely to be the transfer box. What I don't follow is how the noise can disappear, then all seems fine. It would seem to be the gearbox and a knackered bearing possibly the main shaft. Clutch now does not engage and so the thrust bearing has gone.

It's cost me my job as it's my only transport - obviously I've got to them off but any advice/comments I'd be grateful for as I haven't done Landrovers before.

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Have you stripped the splined joint in the propshaft?

Have you got an overdrive?  {The clutch connecting it to the gearbox can strip}

Transfer box seldom gives trouble.  S2/2a gearboxes can suffer from broken layshafts but S3 all-synchro are different.  If the layshaft snaps the thing can still be driven in top - moving off in low ratio.  (Test - don't drive far.)

 

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1 hour ago, secondjeremy said:

Have you stripped the splined joint in the propshaft?

Have you got an overdrive?  {The clutch connecting it to the gearbox can strip}

Transfer box seldom gives trouble.  S2/2a gearboxes can suffer from broken layshafts but S3 all-synchro are different.  If the layshaft snaps the thing can still be driven in top - moving off in low ratio.  (Test - don't drive far.)

 

Many thanks for your reply

a] no just been out to check

b] no - I know what you mean though as I have had other cars with overdrive.

c] Hopefully not transfer box then

One thing I forgot to mention was that I get a kind of jinking when a road is a little uneven like many here in Lincolnshire. Slowing right down seems to cure it. But again I am unsure what can cause that.

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1 hour ago, jessejazza said:

One thing I forgot to mention was that I get a kind of jinking when a road is a little uneven like many here in Lincolnshire. Slowing right down seems to cure it. But again I am unsure what can cause that.

That sounds like it's in 4x4 in high range?

That means a risk of breaking diff/halfshaft.

Do you have any drive at all ? In low 4th for example - crank over in gear to check etc.

Steve b

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8 hours ago, steve b said:

That sounds like it's in 4x4 in high range?

That means a risk of breaking diff/halfshaft.

Do you have any drive at all ? In low 4th for example - crank over in gear to check etc.

Steve b

Thing is it's just occasionally. As for drive... just checked. Yes - it seems the red lever has slipped... if the red lever is not fully forward one gets no drive. I'm still lost as to what the shreek can be which then clears. I've got to get her out and try and see. Trouble is I am a long distance lorry driver so away all week and don't really get the time to do domestic things until holidays. I'm going to have to try and get another motor to keep me going in the meantime.

Be grateful for any advice/help but I won't be able to reply now until next weekend.

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The shriek could be anything - you haven’t told us a general area that it’s coming from.  It could be a piece of debris in a brake drum, a shoe moving laterally and picking up on the wear ridge inside a drum, a mud shield contacting a prop shaft flange...

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