5 Speed Box: Whirring in 5th after Redline oil change

[JonB]

Hi

My car is back on the road at last, but I have more problems to deal with. Now, after sorting out the gearshift mechanism and changing the gear oil to the terrifyingly thin looking Redline MTL. Now, on the first road test, I noted a loud whirring noise coming up through the gearshift. I'm wondering if it's the Redline.

Some additional information - the gear change has been refreshed with a new-ish rubber bellows and the stick is removable. This latter mod involved removing the anti sizzle rubber and replacing it with a bunch of M10 nuts glued into the cup with a corresponding thread on the bottom half of the lever. It's possible the noise is being transferred by this rigid join in the gearshift but the anti sizzle rubber was solid when removed so I can't think the new join is the problem.

Any ideas? I might try swapping the Redline out for another suitable oil for example.

[nmauduit]

my bet is not on the Redline MTL (though my car is a bit noisy, so that would depend on the intensity of the whirring) - would the gearstick slightly touch the body in fifth by any chance, or pinch the rubber against it?

[vxah]

I have to agree, I would not have removed the rubber from the gearstick as it could well amplify the noise by travelling up the lever? Maybe though you have an underlying gearbox issue that the thicker oil masked?
I was hoping to have a word with the Lucas oil rep at the NEC on Saturday but never found them? I spoke to him about 4 speed oil last year and he seemed very knowledgeable, maybe I can use the same oil in the 5 speed?

[Donels]

Having removed the 'anti-sizzle' it sounds like you have made it 'sizzle' assuming the gearbox is not touching anywhere. While the rubber in these is stiff enough to give a good gear change feel it does act as a vibration break, low frequency stiffness vs high frequency damping.

[JonB]

The noise is definitely coming up the gearstick. When I put my hand on it it changes. So now I?d need to restore the anti sizzle joint. I could do this by clearing all the nuts and glue out of it, then using a flexible sealant to pot a threaded bar in the cup. Any suggestions as to what would be a good compound to use?

[Craven]

On the 4 speed anti-sizzle arrangement the rubber isolation prevents lever noise when standing, when used to change gear the flex in the rubber is overcome and a positive link made between the inner and outer parts, two close fitting washers one above and one below the rubber bush so the force is transferred by metal to metal contact.
FWIW.

[nmauduit]

flexible sealant is going to be tricky to get just right I would think, rather gor for a vulcanizable rubber of sort (hardness controllable by the mix) as you'll need a stiff compound.

What I would try is something tuneable, e.g. rubber being trapped between washers under tension compressed by a nylock nut : see for example the Hollnagel paper

http://gglotus.org/ggtech/elan-5spd/elan5spd.pdf

that way one can control the amount of "play" while avoiding metal to metal contact (disclaimer: some fettling required)

[2cams70]

Unless it's something really obvious (eg. metal to metal rattling contact somewhere) it's going to be easier to change out the gear oil and try again to eliminate that possibility first rather than stuff around with further mods to the gearstick. "Whirring" noise does not sound like a "Sizzle" to me!

[Donels]

You may get a rubber bush, metallastic type, that you could glue in place. Check the Robush web site. They have a wide range with full dimensions.

[vincereynard]

On mine, the top does not mechanically touch the lower lever other than through the epoxy.
You've been in it, it does not make any noticable 5th gear noise. (Bit of a sing in 3rd perhaps.)

You can still change gear with the top part unscrewed.

Take it for a drive, get it in 5th and take the top half off.

If the noise is still there, it is not the lack of anti- sizzle.

Any kind chap feel inclined to lend Jon a working, normal 5 speed lever to check?

[Mick6186]

Hi,
I removed the central rubber bush on my 5 speed gear stick and the gear noise increased noticeably.
I purchased a Ford Cortina gearstick on ebay for ?25 and when fitted the noise disappeared, but the 5 speed still has a slight whirr!!
Mick

[alan.barker]

I thought the 5 speed maxi gearbox used Engine Oil
Alan

[nmauduit]

I thought the 5 speed maxi gearbox used Engine Oil

in the Austin maxi it certainly did - and redline MTL is closer to that than a heavier grade. This point has been discussed several times on the forum by people more knowledgeable than me about lubrication, and 2 separate aspects were to take into consideration (gear selection via synchro, gear wear from load), from which I concluded I should go for MTL after the Lotus 5 speed conversion on my S4.

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[derek uk]

Please ignore this comment if I'm moving OT but I think that 5th is an indirect gear, 4th being direct. Indirect gears tend to be noisier than direct so can I ask if 4th is quiet? I frankly can't see the point in removing the anti sizzle mod. It's fitted to cure a problem. I've not seen a report that has said that MTL has made a negative difference to how a gearbox behaves. Normally, running quieter and a improved gear change is mentioned.

Derek UK

[JonB]

Hi Derek

You?re right, 4th is much quieter. And yes, I too read all those glowing reports from Redline users, that?s why I chose it (despite the cost). Vince?s idea is a good un that occurred to me yesterday (great minds and all that!) and I do not know why I didn?t give it a go before posting. Long story short, the noise disappears once the top half of the stick is disengaged. Indeed, with it screwed on loosely so there?s a tiny bit of play it improves things tremendously. I will have to reinstate the joint somehow.

Regarding altering the joint in the first place, you do it so that you have better access when removing the gearbox. You can take the box out with the lower part of the stick in place - otherwise you need to lift the tabs to unscrew the bottom cup, and it?s tricky doing this when the box is in the car.