MK1 S-Special Gearbox/Diff Grinding

 Hi all,

Recently purchased my Eunos and have been on a few ‘spirited’ drives in the past month or so since purchase, in that time I’ve carried out some remedial repairs/modifications with the help of the forums technical articles (Electric aerial repair, relay and switch for heated rear window, new gearknob…)

On a recent drive without the radio on (prior to aerial repair!) I noticed a grinding noise coming from the drivetrain when coming off the power and using engine braking, depressing the clutch immediately stops the noise. Also with the car stationary the revs are solid, depress clutch they remain solid until a gear is selected (With clutch still depressed)… they then drop a couple of hundred RPM.

Hoping not to open a can of worms… but is it either the gearbox or diff? I’m thinking there is a gearbox/clutch issue? But when driving the noise comes from the rear of the car?

Any advice/direction greatly appreciated!!!

The grinding is probably the diff. The first thing to do is make sure it has some oil in it. If so, it’s not worth worrying about until it gets proper loud - then fix it with a second hand one…shouldn’t be much. Might never get that far, though.

The second problem is more likely a faulty clutch switch.

Cheers for the reply! Will be changing the gearbox and diff oil asap.


Are new clutch switches available anywhere? or am I looking at refurbing it?


Thanks again.

Used clutch switches are cheap, but normally it’s the rubber stopper on the clutch switch that it presses against.  The stopper falls off and the plunger on the switch doesn’t get pushed far enough to engage the contact.

They can also be refurbished easily enough. If it’s not as Andrew says, then it will either be a broken spring or dirty contacts.

However, the first step is to see if that’s what’s actually wrong. Disconnect the switch and test for continuity to ground from the switch terminal. There should be continuity when the clutch is depressed, but not when not.