3500s box, how noisy?

[Philippe Holland]

After 36 years of hibernation, I finally drove my newly aquired 3500s around the car park! The gearchange is hard due to the nylon gearlever accorn having been replaced by a cylindrical section of teflon, but what concerns me the most is the sound of the box, somewhere between an Austin seven and an old london taxi. In neutral there is some chatter and in first/second a good old whine....how quiet/noisy should this box be?
Many thanks, Philippe

 

[harveyp6]

They are never silent when driving, but shouldn't really be noisy in Neutral. Make sure all the transmission tunnel access points and the gearlever are sealed as they should be, make sure it's topped up with 20/50, and then if it's still noisy the only thing you can do is take it out and have a look why. If it's noisy in Neutral the normal culprit is the first motion shaft bearing, but as you say it chatters it could be chipped gears, as they aren't up to the job.

 

[Dave3066]

Mine gets a fair bit of use and it whines in every gear bar top. It developed a slight noise in neutral a while ago which disappears when I dip the clutch so probably a bit of bearing wear. The gearbox on mine has always whined and I've done close to 40k miles in 2 1/2 years with no (apparent) worsening. Regular oil changes and a leisurely driving style help too no doubt.

Your car probably just needs to be driven more to get things moving.

Dave

 

[ghce]

Suggest giving the car a good run and then draining the oil whilst any wear products are still in suspension and inspect to see how much metal comes out.
'
Graeme

 

[chrisyork]

Hi Phillipe

The 3500S box is known to be a weak box, although I had the pleasure of driving an absolutely perfect one a couple of months back. They normally sart to show distress by wanting to jump out of gears, particularely reverse, which has its very own lay shaft. So start by trying to drive it in reverse - if it doesn't jump out you're on a winner! It will tend to be much more obstructive when changing gear than a modern box but it shouldn't be excessively noisy.

If you get to the point of deciding it needs a rebuild, the bad news is that there are key components not available. The good news is that the 5 speed LT77 box from the SD1 is a reasonably simple swop - see Stan "Vaultsman"'s recent thread on doing just this.

Chris

 

[dmcsweeney]

Phillipe,
as the other have already said, it's not the quietest box in the world! The rattle in neutral could be something as simple as the clutch release bearing, which will still keep going for years. As Chris said a tired box will jump out of reverse. The original 4 speed in my red car did this for a long time, until eventually I couldn't even hold the lever in reverse any more, and had to resort to driving up a slope and rolling back . I resorted to replacing it with an SD1 LT77, and a friend of mine who drove the car to shows for me on a regular basis actually said he missed the whine under heavy acceleration!!
Regards,
Dave

 

[Philippe Holland]

I'm having trouble engaging the gears, but I am pretty sure that this is due to the broken/missing "acorn" at the bottom of the lever having been replaced (previous owner bodge) by a piece of
cylindrical section teflon which is restricting the distance the selector rod can travel.
The car jumped out of reverse a couple of times, but I think this was due to the gear not being fully selected due to the "new acorn" not engaging far enough.
I've got a later longer lever in the post with the accompanying longer tube for selecting reverse.
The French MOT is on Saturday morning, so I'm hoping it will arrive before then.
The idea of kangarooing down the road trying to find 2nd or 3rd gears, driving a car that has not been on the road 35 years on dodgy Belgian number plates (ahemm., cough, cough..)
is already causing a cold sweat!
Knowing my luck, every traineer French plod will be out on the streets Saturday morning looking for "cash/no receipt" fines and the French will beat the English in the Rugby World Cup
which will be happening at the same time the car is being tested!!
I feel like I'm 18 again!

 

[rockdemon]

The French MOT is on Saturday morning

good luck with that...

the French will beat the English in the Rugby World Cup

not so good luck with that

 

[Dave3066]

I've got a later longer lever in the post with the accompanying longer tube for selecting reverse.

I tried one of the longer gear levers when I had trouble with gear selection a while back but felt it was just too long for my liking. I much prefer the shorter lever which I now have fitted. If the gear selection is that bad you'll find the longer lever makes gearchanges much like stirring porridge.

Good luck with the MOT but I have to agree with Richard on the rugby as i want to watch Ireland putting England out in the semi-final then going on to beat the All-Blacks in the final

Dave

 

[harveyp6]

particularely reverse, which has its very own lay shaft.

I can't remember ever seeing a reverse idler gear that didn't run on its own shaft. The only difference to most boxes is that P6's have a guide shaft for the selector fork as well.

 

[chrisyork]

Ah yes!

Chris

 

[Tor]

Might be a silly question, but my box has expensive Royal Purple Synchromax in it, which I put in there but has since regretted it some. I'm thinking of 'reverse engineering' to a good brand of classic 20W50. Is it likely my box will run quieter for it?

My car has covered some 200kkm on the original gearbox. It sings like an old Volvo but charmingly so. It does drop out of 2nd on high-RPM overruns and crunches into 3rd from 2nd at high RPM. Other than that it's all right I suppose... but with this super oil I can hear the synchromesh when shifting. Don't think I'm supposed to and I know I don't like to.

 

[harveyp6]

I'm thinking of 'reverse engineering' to a good brand of classic 20W50. Is it likely my box will run quieter for it?

You could try the Millers 20/50 which was designed to be used in minis which run the gearbox in the sump and use the engine oil for gearbox lubrication.

It does drop out of 2nd on high-RPM overruns and crunches into 3rd from 2nd at high RPM.

That could be the rear flange nut loose.

High RPM use of a 3500S box is a risky business.

 

[Dave3066]

High RPM use of a 3500S box is a risky business.

How high would you consider "high" to be Harvey?

I tend not to take it any higher than about 2500 on gear changes but have had it up to 3500 on the odd occasion if I'm overtaking. Of course it does sit at 3000 at 70mph when cruising.

Dave

 

[harveyp6]

High RPM use of a 3500S box is a risky business.

How high would you consider "high" to be Harvey?

Anything over idle speed.....

TBH it's not so much the high rpm in itself, it's if you nail the throttle to the floor while you're getting there, particularly in first. If you wanted to do 5000rpm in first (for short periods), then if you took your time getting there it shouldn't cause any problems when you achieve it. (Apart from going deaf.) However, as we know, in the real world, that's not the way it happens.....

High rpm in top won't cause the same problems because it's direct drive, not running through the laygear.

 

[Dave3066]

Anything over idle speed.....

If you wanted to do 5000rpm in first (for short periods), then if you took your time getting there it shouldn't cause any problems when you achieve it. (Apart from going deaf.)

I'd be scared to push the engine that high never mind the gearbox :shock:

Dave

 

[dmcsweeney]

Good luck with the MOT but I have to agree with Richard on the rugby as i want to watch Ireland putting England out in the semi-final then going on to beat the All-Blacks in the final
Dave

Slow down there Dave! We have the problem of having to try to beat Wales first :shock: . Not looking forward to that one .
Regards,
Dave

 

[Dave3066]

Slow down there Dave! We have the problem of having to try to beat Wales first :shock: . Not looking forward to that one

Yes Wales do look good but I don't think they've been tested yet and Ireland will certainly do that.

Dave

 

[Tor]

That could be the rear flange nut loose.

I'm in real fear that it's due to a tooth-shaped piece of metal that dropped out of the sump at oil change. I'm guessing it's from a synchro ring. A friend has a dry, low-mileage four speed that I can have for cheap while I save for an R380 to go in one fine day.

Anything over idle speed.....

I've recently removed the engine fan so can enjoy the engine music. This translates to high-risk motoring, then.

If you wanted to do 5000rpm in first (for short periods), then if you took your time getting there it shouldn't cause any problems when you achieve it. (Apart from going deaf.)

And getting ticketed :roll:

Incidentally, and apologies for hijacking the thread here, said friend has a NOS differential with extension tube sitting in a wooden box. What would that be worth? I'm asking because of internal play and the bearing noise I'm getting from mine, considering it for replacement.

 

[harveyp6]

I'm in real fear that it's due to a tooth-shaped piece of metal that dropped out of the sump at oil change. I'm guessing it's from a synchro ring.

A pic would help, (next to a rule to scale it) but if it's steel then it's probably from the synchro hub, where the end tooth next to the location groove for the cone itself has a habit of breaking off, without any drastic consequences once it gets to the bottom of the box. If it was a gear tooth I think you would know all about it by now.