My shifter runneth over -- oil in shifter assembly. Normal?

[FastWoman]

Hi all,

I just finished replacing my shifter bushings with the brass eBay variety. Now it's very nice and tight.

However, when I pulled the boot off of the shift linkage assembly, it was full of gear oil and in fact overflowed a bit onto the ground. Is this the way it's supposed to be?

[Oiluj]

Replaced them in my current and previous 240z and never saw that much fluid. Maybe check the fluid level?

Was the tranny hot and possibly fluid expansion?

I'm sure someone will have the correct answer...

[FastWoman]

The transmission was stone cold and had been sitting for a couple of days. (I'm waiting for a new alternator.)

Looking at a diagram of the transmission, the shifter assembly would/should be well above the oil level in the transmission. I had the oil changed relatively recently by a Z specialist. I presume he knows the correct fluid level for these things, and I would think it would be impossible to overfill. Dunno.

I've read in the Miata forum that the "cup" should be filled with oil, but like you, I've never seen this before, and we're talking about a different car. It seemed strange that the oil slurped over. If anything, you'd expect the oil to drain away over time (into the transmission).

[beermanpete]

The shifter is sealed from the gear box. It should not have 90W in it. You probably have a bad seal on the striking shaft. See the diagrams in the service manual.

[FastWoman]

Well, that's sort of what I've been thinking. However, the shift linkage end of the transmission is elevated at the top of the transmission housing. Wouldn't the oil drain back the other way when the car sits?

FAIW, I've not noticed any oil spots under the car, but the rear of the transmission is a bit oil soaked. I imagine I might drip a bit as I drive. The boot seems to retain the sloshing, but it's inevitable it will ooze between the housing and the boot (as it's done).

[beermanpete]

It does seem like it should but the shaft is horizontal, or nearly so. Any oil that gets on the shaft from oil sling or vapor condensation could (and apparently does) run to the back of the shaft. The striking guide has a pocket in it that will allow the oil to puddle rather than run back into the gear box when the car is parked. Also, the seal will attempt to prevent oil from going past it in both directions (as it should). There are several forces at play trying to push oil out and only gravity trying to push it back in.

Make sure the oil level is correct, an over-full condition will aggravate the problem. Check the oil with the car level. Don't lift only one end of the car when crawling under there to check the oil.

Another contributor to oil in places it might not normally go is a blocked vent. Check the breather vent for free flow. If it is blocked pressure will build in the transmission as it heats pushing oil out anywhere is can manage to flow.

[FastWoman]

I'm going to have to study the anatomy of this thing. Do you know where the breather vent is?

As for checking the oil level... Ooph! The reason I had the Z specialist change the oil was that I couldn't get either of the plugs loose in the first place! Maybe they're less welded into place now that he's broken them loose.

Is it even possible to overfill the transmission? Don't you fill it to the brim at the level of the fill plug?

I'm betting on the breather vent. I hadn't thought of that.

[sblake01]

Is it even possible to overfill the transmission? Don't you fill it to the brim at the level of the fill plug?

Actually, there is a prescribed amount according to the FSM. I believe it's 4¼ pt. for the 5 speed and when I'd fill them with that amount it didn't reach the fill plug.

[LeonV]

Actually, there is a prescribed amount according to the FSM. I believe it's 4¼ pt. for the 5 speed and when I'd fill them with that amount it didn't reach the fill plug.

That is just an approximate amount. If you look in the FSM, it shows that it must be filled level to the fill plug.

[sblake01]

I can recall having that argument some years ago. I wasn't trying to start it again; simply saying what the manual says capacity wise. Also listed under 'approximate refill capacities' is engine oil and I've never added any more than the FSM says except on my roadster which had an aftermarket deep oil pan. I actually don't see where it says to fill to the plug in either the manual trans section or the general info section. Now, I'm talking the 280Z FSM not the 240Z FSM. If it does, you don't need to show me because, at this point in time, at least for me, it's a moot point.

[doradox]

I can recall having that argument some years ago. I wasn't trying to start it again; simply saying what the manual says capacity wise. Also listed under 'approximate refill capacities' is engine oil and I've never added any more than the FSM says except on my roadster which had an aftermarket deep oil pan. I actually don't see where it says to fill to the plug in either the manual trans section or the general info section. Now, I'm talking the 280Z FSM not the 240Z FSM. If it does, you don't need to show me because, at this point in time, at least for me, it's a moot point.

So when you top off the oil level do you drain the engine and refill with the amount of oil stated in the FSM or do you fill to the full line on the dipstick?

How would one top, or even just check the level, off the trans or diff if the only way to know how much fluid to put in is to drain it and refill with the "recommended" amount?

Steve

[sblake01]

I've rarely 'topped off' the oil level on any vehicle I've owned except for the few I owned that either 'used' or leaked oil. So, yes, in most cases I would do an oil change and use the recommended amount of oil and not really worry much about it between oil changes. With differentials/transmissions we're talking about much longer intervals than engines obviously so, unless the trans or differential was leaking or showing so other sign of low oil/lube the only time I'd bother with them is when I did a diff. or trans. service in which case I'd drain them before I'd refill them. This is Sarah's thread and it needs to get back to her topic. All I did was state what the manual says about capacity. I didn't ask for any technical advice nor is anyone bound to approach that area of their vehicle(s) as I do. In fact, I don't think I've ever asked for technical/mechanical advice in my 10k+ posts here.

Edited November 30, 2011 by sblake01