Strange noise and vibration

[sprintsoft]

Hi Jon,

Wasn't meaning to disrespect anyones favourite oil there!

The resonance I have is in a Sprint 4 speed box, it's in very good nick and runs almost silently on EP80, the MTL just amplified the usual layshaft noises at idle and didn't signiificantly improve the shift.

I do run MTL in a 5 speed +2 and I would say in that application it helps the synchro engage more smoothly, but again it is noticeably more noisy, I added some soundproofing around the base of the gear lever for now so it doesn't sound so 'busy'. For a worn box like this it's probably better to use the MT-90 (75w90) version, I intend to try that next. (MTL is 75w80).

Iain

[JonB]

Do let us know how it goes.

For my part I?m relieved that someone else has experienced additional noise after putting MTK in a 5 speed box. Means I?m not imagining it! I also experimented with extra soundproofing round the gear shift but that makes it harder to shift. As it is cold and miserable in the garage at the moment I?ve left it alone. No doubt my newly fixed clock is running the battery down.ll

[sprintsoft]

OK, will do.

ref your clock, or, like me you didn't realise the light was on inside the glove box...

Nowadays I wouldn't be without my CTEK - highly recommended!
https://www.ctek.com/products/vehicle/mxs-3-8

[2cams70]

(although I am pretty sure the prop shaft wasn?t balanced).

It's very important that any rebuilt propshaft is balanced before fitment.

[2cams70]

Grab the propshaft yoke where it enters the gearbox and check for excessive sideways movement. The Redline may not offer good lubrication properties for parts that have marginal lubrication - i.e not immersed in oil. It may have caused damage to the extension housing bush.

[rgh0]

I dont understand much of this thread and people appear to be drawing conclusions based on very little real data, so hard to give any meaningful response .

But in the end run the oil that you personally think is best for your use and your gearbox as things like noise and vibration and change feel are very subjective and personal to individual users

regards
Rohan

[JonB]

Hi Rohan

In my case it's 60% observation and 40% desperation. And I'll wager the gearboxes you race with are way less worn than mine.. but anyway, I've documented my problem on another thread; suffice to say I will try swapping out the Redline (naturally I will keep it in a bottle) for a more traditional SAE80 oil and see if it improves matters. Naturally, a gearbox rebuild would be in order but it is too expensive and I am not keen on pulling the engine + box out a third time, just yet.

[JonB]

(although I am pretty sure the prop shaft wasn?t balanced).

It's very important that any rebuilt propshaft is balanced before fitment.

Agreed. The guy who fitted the new joints checked the shaft for true running but not balance, as his balancing machine was lost in a fire not long ago. As a result I paid way less than I expected. The main issue was the sliding joint which had sideways play - the vibration that caused has gone, so I am hearing something new that was probably being masked by the old noise. But it is not too bad.

[alan.barker]

Hi Jonb,
you have a 5 speed maxi gearbox that was designed to run on Engine Oil like the Maxi.
Imho i would not put sae 80 hypoid Oil.
Does Lotus say put 80
Alan

[512BB]

It should be noted that a previous poster on this thread is no longer with us. Rest in peace Mick G, now in Lo Lo land and looking down on us, hopefully with a smile on his face. A good man.

A while back, someone posted about not coming back with how their problem was resolved, or if it was resolved, and that that was one of the reasons why there are few posters on here, because having spent time helping people out with a suggestion, many folk do not bother to come back with how the problem was sorted.

How about it Paul, are you still with us? You might be able to help out a fellow LE.Neter.

Best,

Leslie

[JonB]

Hi Jonb,
you have a 5 speed maxi gearbox that was designed to run on Engine Oil like the Maxi.
Imho i would not put sae 80 hypoid Oil.
Does Lotus say put 80
Alan

Yes. The advice was changed, I believe, from motor oil to SAE80 at some point soon after the introduction of the 5 speed box.

[Craven]

Unforeseen consequences, I?m reminded of the time when multi-grade engine oil started to appear on the motoring scene, hailed as greatest advantage in lubrication ever and consequentially used with enthusiasm by classic car owners. Very soon after a few miles precious engines started to burn a lot more oil or in some cases seize up, but I?m using this new wonder oil! This can?t be the problem.
Oh yes it was, new multi-grade oils contained a detergent that very effectively loosen built up carbon deposits in the old engines that then circulated within the oil causing in some cases catastrophic failure.
More to the point, perhaps these latest gear oils contain additives that have removed a past build-up of an old protective layer that provided a degree of dampening on worn parts.
FWIW.

[fireblade]

Paul


I too have experienced a strange noise and vibration from the rear drive at speeds between 60-70 mph in 4th gear. Replacing the oil in the diff with MTL didn't change the situation. Coincidently the diff bearings started to become noisy so I removed the diff and prop shaft and had the diff bearings replaced along with new UJ's and the prop shaft balanced. The Lotus technician who has 30years+ experience who did the work for me advised I should revert back to Castrol EP80 which I did. The car now drives like a dream with no hint of noise or vibration.

[Donels]

If the uj's or yoke have been changed and the propshaft not rebalanced then you run a high risk of vibration and noise. The bearing cups are unlikely to be pressed into exactly the same position meaning that the centre line of the propshaft moves resulting in out of balance.
Ideally the propshaft should be removed and rebalanced properly but you can attempt to rebalance by using jubilee clips. Two clips close to the end that has had the UJ changed with their screw fasteners opposite each other are in balance, rotate one relative to the other and you introduce an in balance. Max in balance is clearly when both screw fasteners are aligned. Rotate the clips to move the position of the in balance. So with a lot of trial and error you may be able to improve the OOB. The OOB should be in one of 4 positions relative to the bearing cups.

[JonB]

Yep.

The car is much improved though. A great deal of vibration is gone since the new sliding joint was fitted. I may try the trial and error approach as it means no need to pull the diff and cough up yet more money. I had a mate with an MGB who managed it. But having said that, I?m not entirely convinced the vibration is from the shaft. Having experienced it a few times before, it doesn?t sound quite the same.