Miata tranny/clutch problem

A friend has a Miata and had it break down on him today and the symptoms confuse me. From what he tells me, he was driving it hard and everything was fine. He went to go park it and shifted into reverse and let the clutch out. Nothing happened. The car went no where. Tried all the forward gears and nothing happened. No strange noises or anything. As a matter of fact he can row thru all the gears while not using the clutch and the car goes no where. He "says" the shifter feels as it always has and the clutch feels the same as always. Any ideas?

You don't say the year, but check this out:

http://www.miata.net/garage/stuckreverse.html

I saw that already but their description sounds as if the tranny is actually stuck in reverse. This doesn't seem to be the case at all. The car will not move at all. Seems as if it's stuck in neutral. You can shift into any gear either using the clutch or not while the engine is running with no effect.

Can he just move the stick around or does he actually feel it slot into gear?

I may find out differently later but at the moment he says he can feel the stick slot into each and every gear. He's tried to put the tranny in each gear and let the clutch out and nothing happens. Then he decided to keep his foot off the clutch and he could still go thru each gear with the engine running with no effect. Strange.

Can the car be pushed? If so, he's not stuck in any gear, basically stuck in neutral. If he can slot it in gear, can the car be pushed?

Or, a rear axle is no longer connected to the diff; either broke or the cv joint broke.

pressure plate

I once had a RX-7 that exhibited this. When I pulled the trans the clutch face was completely ripped off. This was a 12A powered RX-7 so didn't have a lot of power. About the same as a stock Miata now that I think about it.

I suspect the previous owner had tried to drift the car and destroyed the clutch.

You mention the guy was driving the car "hard". Could the hard driving he was doing have destroyed the clutch?

gjz30075 wrote: Can the car be pushed? If so, he's not stuck in any gear, basically stuck in neutral. If he can slot it in gear, can the car be pushed? Or, a rear axle is no longer connected to the diff; either broke or the cv joint broke.

Yes, it's like it's stuck in neutral even though he feels as if he can shift the car thru the gears. Even in gear (supposedly), the car can be pushed.

Xceler8x wrote: I once had a RX-7 that exhibited this. When I pulled the trans the clutch face was completely ripped off. This was a 12A powered RX-7 so didn't have a lot of power. About the same as a stock Miata now that I think about it. I suspect the previous owner had tried to drift the car and destroyed the clutch. You mention the guy was driving the car "hard". Could the hard driving he was doing have destroyed the clutch?

No, he was pushing the car and shifting quite a bit thru some twisties but nothing that would have destroyed the clutch. The clutch does have HIGH miles on it but every clutch I've had that's gone bad has exhibited some sort of sound or mechanical problem. This isn't the case here.

Any funky noises?

sounds like he blew the diff

dbgrubbs wrote: No, he was pushing the car and shifting quite a bit thru some twisties but nothing that would have destroyed the clutch.

That's what he TOLD you right? Ok.

Let us know what you find once you pull some parts.

The fact that he can row through the gears without using the clutch is telling me that either there is no clutch engagement whatsoever, or there's no shift linkage. Do the reverse lights come on?

Don't really matter much. The transmission's coming out unless it's the classic "stuck in reverse" problem. Used Miata transmissions are about the same price as Miata clutches. So pull it. If the clutch looks good, stick a transmission in there. Heck, might as well do the clutch while you have it all out anyhow.

pull the trans and if the clutch looks good check the trans by putting it in gear and turning the input shaft and see if the output shaft turns. If it turns it's the pressure plate like I stated before. I had the same thing happen in my car after some spirited driving, pressure plates don't break often but when they do it's all at once and the car acts like there's no clutch.

Wouldn't you feel a broken pressure plate through the pedal?

Keith wrote: Wouldn't you feel a broken pressure plate through the pedal?

When it happened to my car the pedal felt normal.

Thanks guys. He had it towed to a shop he knows and they'll tear into it today. Hopefully it's just a clutch that's needed. I wouldn't doubt it since it's still on the original 210K mile clutch!! The symptoms are just confusing.

Well, the shop was convinced it was the clutch. He had it towed home so I could change the clutch for him. Nothing looked out of the ordinary. New clutch, pressure plate, turned flywheel and new throwout bearing. Got it all back together and everything was well until.............it happened again. After reading some of the Miata forums, my best guess now is that the clutch master cylinder is shot. No, it's not leaking externally but from what I've read that's not out of the norm. Fluid leaking past the seals internally. Makes more sense since the symptoms come and go.

Any opinions on this? Thanks

Does the fluid level go down in the master cylinder at all?

Actually, did you check/change the clutch hose? It's not exactly unknown for hoses containing brake fluid to swell up internally. They'll start acting as a one-way valve then and might as well hold the clutch 'open'. Stick a braided hose on and see if that cures the problem.

The fluid level was a "bit" low but nothing terrible. Haven't checked the clutch hose yet. I'll look at that too. It's a possibility.

From your description it sounds to me like something is holding the clutch in its disengaged stage, otherwise you wouldn't be able to select several gears without crunching and/or the car moving.

So I guess the unpleasant task is to work out which of the parts involved is jamming the clutch open...

Simple test for the hose would be to open the bleed nipple on the slave cylinder carefully as the fluid might be under pressure. Let it drain a little and wait until it doesn't appear to be under pressure, then check if the clutch is engaged again.

Well, the clutch was due to be replaced even though it was still working. I'd put the clutch hose in the same category. I'll go ahead and replace it since a replacement is cheap and see what happens. Normally I don't like chasing problems with parts but with over 200K miles on the car and it's mostly original, I don't mind small parts like the clutch hose, slave and/or master cylinder. They've exceeded their lifespan anyway.