I think this is bad news. I have a whirring sort of noise that I only hear when the clutch is engaged. If I have the pedal pushed down, no noise. Pedal up, transmission in neutral or in gear, I hear the noise.

I did replace the clutch master and slave a few weeks ago, and didn't have the noise before that. This is a SA, and I swapped the complete hydraulics set off a S2 into the car. Could that be related? I think the only difference is the thread pitch and nothing else. But could I have something misaligned?

 

Are you sure the tranny fluid is full? Other than that, maybe the torque on the pp bolts wasn't even or the throwout bearing, did you lube it?

 

Throwout bearing?

 

pilot bearing? my fb was doing that b4 it died and when i pulled the engine/tranny the pilot bearing was stuck to the imput shaft of the transmission.

 

Have you heard the noise in all gears?

If you ONLY replaced the hydrolic components and accidently had something misaligned, it would be a clutch engagement issue, because of the slave cylander rod not pushing the throw-out bearing arm properly.

Can you hear where the noise is coming from mainly?? eg front middle or rear?? That would tell you best where to go. From the description, I would say its related to the clutch, if its not from lack of tranny or rear diff fluid. Fortunately doing a clutch on an FB is pretty simple, just time consuming. Hope thats not the case though.

The thing to remember with these is that parts dont need a reason to fail. As Ive learned all too well.

If it turns out to be the pilot bearing - just rent the tool made to remove it. I think either RacingBeat or Mazdatrix rents it. Thats what I did, and from the looks of it, I didnt even want to think about removing it without that tool. Good luck.

 

Sounds like maybe the throwout bearing is not fully disengaged when you let off the clutch and its still spinning with the clutch spilnes. Thats my best guess. Not sure why swapping in the hydraulics would affect this but if they don't seat right on the pivot arm then maybe its not releasing the TO bearing competely. Make sure the end of the slave cylinder rod is positioned on the detent for in the pivot arm.

 

i concurr ....throw out bearing

 

Good ideas. Thanks.

1. Will check fluid level. Meant to drain and fill after buying the car, but got sidetracked dismanteling the old car.

2. Lube the TO bearing? Not sure if I did when we swapped in the engine from the old car. That probably means I didn't. What am I supposed to lube it with?

3. I didn't touch the PP or clutch disc or flywheel when we swapped engines, so whatever was on there may very well have been on it for the 137k miles the engine has.

4. I bent over last night at a stop light with the engine idling and the tranny in neutral, and it sounded like it came from the front of the tranny but my ear was over the shifter, so most of the tranny is forward of that point, so who knows. I haven't lifted the hood to listen.

The noise, now that I think of it, seems to have started when I swapped the hydraulics, so maybe something is misaligned, like the end of the rod coming out of the slave to the fork. I'll check that along with fluid levels tonight if it stops raining.

 

I've had that same exact whirring noise on an SA when the clutch was out, turned out it was the throwout bearing making noise on the shaft because it wasn't attached to the plate properly.

 

Update.

Checked level in tranny last night. The fill plug was a bitch to get out, and the drain plug wasn't tight at all. Anyway, it was quite low. Based on what I drained out, I'd guess it was maybe half the specified volume of lube in there. Didn't have time to stop at the store on the way home, so I filled with what I had on-hand at home, some no-name 80W90 plus some Valvoline 75W90 and a little bit of Mobil One 75W90. Started the car up and let it sit in neutral with the clutch engaged. At first, I heard the same sound, then it stopped. Drove the car this morning. Started up, heard the sound, then it stopped. Didn't hear it on the way to work. When I parked at work, I let it sit in neutral with the clutch engaged and heard it, but much quieter than before.

I'm thinking of draining again, refilling with better lube and maybe some Lucas Oil Stabilizer. Good idea? Bad idea? Other ideas?

This is a SA 5-speed tranny. I have another tranny worked very well, but it's from my '83, so it's not a direct replacement.

 

I think your throw out bearing is wearing out. The noise being subdued now is a case of the higher fluid level in the tranny deadening the amplification. Chances are, the problem is still there.

 

i am also going to say that its the throwout bearing. pilot bearing, maybe but you'll need to pull the trans for this one. while you're in there, change the pilot bearing and the clutch. this whole deal can be done in an afternoon.

 

put synthetic in it https://www.amsoil.com/StoreFront/mtg.aspx

 

Everything I've read, including the transmission info at Mazdatrix, says you hear the noise from a bad TO bearing with the clutch pedal depressed. I hear nothing then. I get the noise when the clutch is engaged.

 

Throwout Bearing would make noise if the clutch is out, no in correct? i replaced my thinking same thing. I later discovered it to be the bearings in my tranny. Makes sense, its got almost 200,000 on the damn thing.

 

That what I think is the problem, maybe the input shaft bearing. From the FSM, it looks like you have to tear down the whole tranny to replace it. As far as I know, this tranny has a little over 100k miles on it. I have a FB tranny with ~140k on it, maybe I'll have to swap it into the SA. Unfortunately, that's not a direct swap.

 

To clean up the synchros and any bearings that are lubed internally you can try the old Datsun racing trick (which works great). Fill the tranny with a 50/50 combination of specified gear lube and automatic tranny fluid. The detergents in the ATF are great for cleaning out all the sludge that builds up over the years, yet still provides excellent lubrication. I have done this on a couple of "problem" trannys and it has worked great everytime. Tranny will shift smoother and faster, and will probably live a lot longer without the sludge in there.

 

So 50% ATF and 50% regular gear oil huh? Do you drain it after while or leave it in there til its time to change the fluid again? I'll have to try that, i have a hard time getting to 2nd and 3rd if I shift quick, and I'm not talkin drag racing, tire chirping shifting, just a quick shift at a high RPM.

 

I don't think it can hurt to try this. I think I have a bearing on the way out though. I'm going to swap in the FB tranny, but I'm going to swap in the LSD rear at the same time. That's a few weeks away from being ready.

 

No need to drain afterward. This is what I've been running in all of my cars for nearly twenty years now. Never had an issue, and always see an improvement. I figure if its good enough for the Datsun racecars, then its good enough form me. This information, by the way, comes from the book "How to hotrod and race your Datsun" and was written with the assistance of the two major Datsun race teams.

 

I wouldnt even use Lucas anything to oil my door hinges lol. Stick with a good quality oil brand, syn or non syn for engine, tranny and rear end. Just change the fluids at recommended intervals or earlier, dont use additives. I have heard bad things about oil additives causing foaming issues. Good quality oils have been engineered with everything required, additives could throw the chemical balance out of sync.

 

I run straight ATF in my 78 280z 5 speed and have for years.. shifts better than it ever has with the 80/90wt. I wouldnt hesitate to do the same in my 1st gen 7, 5 speed. All of the new cars with 5 or 6 speeds all use ATF now and have since the mid 80's. A tranny with a weak syncro will shift noticably improved with ATF over 80/90wt.

 

ATF is great for adding a half quart to the crank case for 50 or 100 miles if you have extremely dirty oil to help clean out the inside of an engine, rotary or piston engine. Did this several times to the 7 when I first got it. If I buy a used car from someone, that is usually what I wind up doing, adding a half or full quart of ATF to the oil to clean things up. Drop a little oil to make room, dont over fill the crankcase. If it is a car with extremely dirty oil or sludgy engine, I have many times dropped the oil and filled the crankcase with pure ATF and run for 10 minutes, drop oil again, change filter and add fresh quality oil. I would never recommend any type of oil flush or diesel fuel as a crankcase flush, too violent a cleaner and might break sludge loose and cause a problem, but ATF is a much milder cleaner and as someone earlier said, it is just a high detergent oil.

You can also add a half qt or so of ATF with your fuel at each fill up as a cheap alternative to the pre mix ($1.50 a qt - maybe even an off brand ATF is less expensive) and the ATF will help keep your fuel tank from rusting. ATF mixes great with fuel, I do this all the time, especially if there is any ethanol mix in the fuel, the ethanol or any alcohol tends to really dry the fuel out.. most octane boosters contain ATF as part of the mix, since most octane boosters are just alcohol.

I use ATF for assembling new engines and even fired up my supercharged 03 Cobra new stroker engine for the first time for 10 minutes with pure ATF to let the rings seat quickly - thinner oil and high detergent qualities to get the assy lube out then changed the oil and filter again to good ole GTX.

Can't say enough about ATF, has many uses and the only additive I would use anywhere on any car. It is a faily thin high detergent oil.. great stuff!