So I've been driving my Z lately, and I noticed about a week ago, a weird noise was coming from where I had originally thought was the fan blower motor. It sounded like a leaf had fallen into the air vent, and worked its way to the squirrel cage, and was spinning along with the cage. The noise would come and go, so I didn't worry too much about it. Today I drove it down the road, and the noise got even louder, and seemed to only happen when the transmission was in gear. If I was at a stop, and revved the engine, no noise. But as soon as I engaged the clutch and the driveline began to spin, the noise would be evident. It seems to vary with engine rpm (but noise is not coming from the engine from what I hear) and sometimes goes away for no good reason. I haven't had a chance to take a look at it, since it's dark and all right now, but I did crawl under it for a few seconds, and it seemed like the transmission was leaking fluid from the rear output shaft seal since it was flung all around on the bottom of the car.

Tomorrow (as long as it doesn't rain) I was planning on checking my u-joints, and draining my tranny fluid to see if there were any metallic shavings in it, and refill it to see if that was the issue. I'm also probably going to get a rear output shaft seal, if the auto parts store carries those as well. The noise seems to be coming from the passenger side of the transmission tunnel, and now sounds like a metallic scraping. I'm not sure exactly how to describe it, but imagine what a leaf in the squirrel cage sounds like, but then turn that into a metallic noise.

If it's the transmission, I have a couple spares that I can try. I just don't want to do a tranny swap to find out the problem is even easier than I had thought.

 

Last time I heard that sound, we made it from Boulder to Moab in 4.5 hours... and lost 5th gear about 10 miles from town. The sound started a little East of Grand Junction, and was pretty noticeable by Fruita. Didn't seem bad, but turned out to be fatal to the tranny. Limped in with 4th, and could barely get it in to gear to get it repaired in town. Ended up with a longer vacation while we waited for FedEx to deliver a transmission over a holiday weekend. Learned that Moab is just too far from anywhere to have overnight delivery, and that rental Jeeps are a *lot* of fun. In our case, it would have required a tranny rebuild with at least a new 5th gear and syncro, plus several of the bearings. Seals were fine, it was an internal wear issue (mostly due to the not-a-true-5th on the early 5 speeds). My wife wants me to put a brand new rebuilt ZX 5 speed (true 5th, much stronger) in the '78 I'm restoring now. Sounded good to me. I like Moab a lot, but being stuck there was no fun.
good luck,
Dave

 

Thanks! I had a feeling it might be linked to the tranny. Maybe I'll throw on one of my spares if I get some free time this week.

 

sounds like it could be an input/output shaft bearing or something else internal along those lines.