3rd gear grinding on downshift

[Jiggerachi]

I have noticed recently that sometimes my tranny will grind while down shifting & sometimes putting it in reverse. The other day after a long drive on the freeway I discovered it would grind on every 4th to 3rd downshift over 40mph, but it would not grind at all below 40, no other gears would grind on downshift, upshifting is & has always been smooth. Going to work this morning I could not reproduce the grinding over 40mph, but I dont think the issue is solved.

Any idea of what might be causing this??

I just put a fresh batch of mobile 1 gear oil in it about 4 months ago, & I havent seen any spots on the ground, but I have been smelling a slight oil burning smell after a long drive, a smell I have not had since I fixed the leaky CAS. Maybee theres a small leak thats just burning off on the exhaust, but maybee not bad enough to be leaking? The smell could also be on the same timeline as the grinding...or that could just be in my head.

Would low gear oil cause grinding on downshifts?? At any rate im going to check & replace any missing gear oil this weekend, I just hope this dosent mean $$$, because as of this month, I have none(moving into a house).

Thanks guys.

[POS Racing]

A new slave cylinder cured the grind in My '92. Do you possibly have a leaky slave cylinder?

[Jiggerachi]

Actually...I was going to look at the car with a coworker of mine(240SX driver), popped the hood & first thing we notice is the clutch fluid is almost completely empty Do you think this would have anything to do with it??

It has to be a recent leak, last autocross it had to be full, but I admit I really havent checked it lately

Im going to top it off tomorrow & begin the search for the leak.

Question, is bleading the clutch system necessary, or should I just fill it up?

[POS Racing]

I'd bet you have a leaky slave cylinder!

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

[sammm]

Question, is bleading the clutch system necessary, or should I just fill it up?

If you drained it dry and it's sucking air, yes it will need bled. Otherwise just top it off.

[onething]

I'd ignore what POS said and check the slave cylinder.

[channelmaniac]

Slave cylinder is cake to replace... I did one on my Spec Car... took about 15 min from start to finish... The neighbor's daughter was outside playing so I recruited her to work the clutch pedal while I bled the slave cylinder.

If you want to make it a one man job, get a speedbleeder for it.

RJ

[Jiggerachi]

Well, topped off the clutch fluid, still scratching 3rd on the way home...

I guess I need to bleed the clutch, ill do that as soon as I can. Also discovered a ton of fluid(oil of some sort) all over the back of the oil pan & tranny, dammit, not again.

I need to replace the slave cylinder I guess, but I have no money at this time, so ill keep some spare fluid in the trunk for now.

Also, I replaced the original(I think) o2 sensor, should I be noticing any type of power gain, or would it only be reflected in gas mileage. I would hate to think I just payed $60 replacing a pain in the ass part that wasnt bad, I guess ill find out when I fill up again.

Thanks guys

[POS Racing]

Did you check the slave is it leaking? Did you get any fluid out of the boot?

You do know if the slave fails completely you will not be able to actuate the clutch. So you'll have a stationary Miata.

[Carmen1990]

Did you check the slave is it leaking? Did you get any fluid out of the boot?

You do know if the slave fails completely you will not be able to actuate the clutch. So you'll have a stationary Miata.

Not completely true.. I drove home from school one day when my slave cylinder completely went out.. Wasnt pretty and dont ask how :mad: ... Yeah check that slave cylinder now before its too late

[altiain]

Better yet, just order a brand new one. They're only about $20 through Mazdacomp.

[channelmaniac]

When I bought the replacement for my Spec, it was $28 through O'Reilly Auto Parts... they had a rebuild kit for $7+change.

If you can't afford a new one, hopefully you can stop by O'Reilly's and get a rebuild kit QUICKLY.

RJ

[Jiggerachi]

Just flushed the fluid, I kept getting tiny air bubbles. After a whole bottle of brake fluid I just said screw it. Would a leak be sucking air into the system??

Took it for a spin & the clutch felt a bit stronger & 3rd wasnt grinding at all, but before I got home it ground once, a small one, but still...


Trusseville has the slave cylinder for $65+ shipping, & I dont have MazdaComp yet. Hows the quality on the O'Reilys part??

I will probably end up rebuilding it unless I can get one for $20 or less.

Anyone by any chance have one laying around??

If I only rebuild it, will this fix my problem? Will I have to eventually replace the whole thing??

Thanks guys

[sammm]

If I only rebuild it, will this fix my problem? Will I have to eventually replace the whole thing??

Maybe. Maybe. (If the bore of the slave is pitted, the rebuild won't fix your problem. Worth a shot for $7 if you're tight on cash)

[Radio-Active]

I would suggest buying the new cylinder. I have not had much luck with rebuilding them due to pitting corrosion(1974 Fiat X-1/9). If you do decide to try the rebuild kit, I may still have a bead cylinder hone for it. I used to work on aircraft as a sheetmetal mechanic and had to use cylinder hones from .1875" to .5" for some of the bad fastener holes.

[Jiggerachi]

Better yet, just order a brand new one. They're only about $20 through Mazdacomp.

Do you by any chance have the Mazdaspeed part#??

[sammm]

Do you by any chance have the Mazdaspeed part#??

See this -
LINKIE

Currently $46.35 at Mazdaspeed.

[Jiggerachi]

Thanks Sammmm!

Channelmaniac, how was the quality on the O'Reilys part? I know the Mazda part would be better, but is it worth it to save a few bucks??

[channelmaniac]

Only time will tell!

I only have about 5 miles on the car since then.

RJ