I recently dropped the transmission pan out of my 87 300zx. It is an automatic transmission, I found these pieces of metal in the pan. Is the transmission still good. Any ideas on where these pieces came from?

I don't recogniZe those. Are they magnetic? (I mean, are they magnets, themselves?)

People sometimes put small magnets inside their oil pans (engine and autotrans) to collect any metal shavings which might grind off the moving parts over the years. I have known a guy whose magnets somehow got picked up into the mix and BECAME the metal shavings. What he sought to prevent, he caused.

_________________
1970 240Z

The pieces are not magnetic, but they have metal in them. I found about 8 pieces. They all have the same thickness, approx 1mm and they have fine grooves on one side.

It might have been a shim, but I'm not familiar with where it would have belonged.

Did your transmission work OK before you opened it up?

_________________
1970 240Z

I have a 1989 300ZX that has transmission issues. I bought this car because it has a rebuilt transmission. The car drove fine when I test drove it before I bought it. There was very little clutch dust in the pan and the fluid was fine.

In my entire lifetime, I have only ever rebuilt one single automatic transmission (and it wasn't a Datsun/Nissan), so I might not be the guy to listen to about this. But if I had bought a spare car simply for the transmission, I would put it into my 'driver' car and just get as many miles out of it as my money would buy me. If the 'box eventually failed, I could then figure out where that metal piece came from, and fix it (or take it back to the company for any warrantee).
Until then, I'd try not to disturb a sleeping dog.

Road testing and daily driving are two of the best ways to determine if something is 'wrong' with your car (IMHO). Do you know how long ago the 'box was rebuilt, or where?

Somebody with greater A/T experience than I have, please jump in here and help this new member out?

Frank T

_________________
1970 240Z

I showed the pieces to one one of the Engineers at work today who worked on transmissions for GM in the past. He said that the pieces may be part of the pads that go on the steel rings or they may have something to do with the bands. I am not sure if I am explaining this correctly. The Engineer was not familiar with Nissan transmissions. I am going to bring the pieces to a transmission shop to make sure.

Could be.
The bands are restrictive contacting or expanding binders or brakes (called clutches) which stop spinning discs, stopping two (or more) gears or shafts so the transmission can shift. The compound planetary gear system is a group of intermeshing gears of different sizes, which take turns propelling each other, resulting in differing speeds btwn the engine and the drive wheels. The bands stop certain gears from spinning, allowing for the difference btwn input and output speeds.
You can get a visual idea of how that works by looking up images for Planetary Gear System.

http://www.google.com/search?q=compound ... 80&bih=702

http://www.google.com/search?q=compound ... n&tbm=isch


http://www.youtube.com/watch?v=p8fAHTeDGiQ


If that's what those are, and if that's all the material which has come off the bands, you should be good to go for another half-million miles or so. That material covers the whole friction surface of each of the bands so there should be a LOT of it left.
If your trans starts slipping (engine racing but car not moving much) or taking a long time to shift btwn gears, then I might have the bands tightened or resurfaced. If that doesn't fix it, then repairing or replacing them (or the hydraulic valves) should.

For all you know, those little pieces might have been left over from the last rebuild. They might have been part of the trans which failed in the first place (requiring a rebuild) and never got washed out during the rebuild. You might actually have a perfectly good transmission.

PleaZe let us know what you learn?

_________________
1970 240Z

I want to thank everyone for their replies. At this point, It seems that I have a good chance that this transmission is fine. I will let you know how it works out.

If it feel like sand paper that is what it is. If smooth, then gasket material possibly. Pan gaskets can have metal imbedded in them. IMO, I hope it is pan gasket.

In the last few weeks, I found the time to swap the transmissions. This transmission shifts fine in my 89 Z, but it seems to shift at a higher RPM than my other transmission. For example, it won't shift until almost 4000 RPM's, unless, you are just going very slow. What are the normal shift points for a Z31? From what I read in the manual, it shifts electronically. Is this normal for an automatic non turbo?

Thanks

ATs shift according to load demand. In other words, if you take off with your foot to the floor, the transmission will hold each gear longer to get as much speed as possible before shifting. If you take off with a light foot, it should shift sooner (btwn 2,000-3,000rpm) for better fuel economy.
The amount of pressure (pedal travel) you put on the accelerator is transmitted to the gearbox by an adjustable rod. If the rod is not adjusted properly, the gearbox can think you're trying to accelerate harder than you really want to, and refuse to shift until higher rpm.
There's also a kick-down switch which causes the gearbox to downshift to the next lower gear (to give more torque) if you suddenly try to accelerate hard from 30mph (passing a bus, for example). If the accelerator rod is not correctly adjusted, that kick-down switch can be activated at times you really don't intend it to.

Somebody with better hands-on experience can give you insight about how to make sure the rod is correctly adjusted.

There may also be an overdrive switch issue involved (just a guess). I know my old Camry and my present Mini both shift at higher rpm if I press the OD button OFF.

Is there a difference btwn the differential gears in your car, and the car this new transmission came out of?

Frank

_________________
1970 240Z

The new transmission came out of a 1987 300ZX. The transmission had less than 6000 miles on it. Your question about the differential gears made me think. I noticed immediately that the car had more torque with the new transmission. Considering that I had also changed a bad oxygen sensor, I thought this was the reason for the increased power. In actuality, the new transmission may be geared lower, contributing to the increased torque. I don't remember seeing a rod attached to the gearbox. I seem to remember that the manual mentioned electronic shifting but I am not sure. Thanks for your help.

Mannnn, I keep forgetting we're talking about a 300zx 'spaceship' here. Forgive me. Your shifting is probably electronically computed according to load, engine speed, road speed, etc. Wayyyy out of my league. The guys at RDZ are far better qualified to respond to this.

But yes, lower ratio transmission gears certainly would give you different performance than your stock gearbox.

_________________
1970 240Z

All automatic Z31 cars have the same transmission, so the one you swapped in should not be geared differently.


Source:
http://www.az-zbum.com/information.transmission.shtml

_________________
Justin
1986 Z31 NA 2+0