blue72 Posted August 22, 2008 Share Posted August 22, 2008 Thought you might like my little story from this week. It involves my '72 240Z and its 1978 FS5C71A 5-Speed transmission. Last Saturday I was driving my Z without a worry in the world until I went to shift into 5th. Bang! and I was in neutral. I found that I couldn't shift into 5th at all and the tranny would no longer stay in 1st or 3rd. I drove the car home in 2nd and 4th instead. I couldn't detect grinding and no strange noises presented themselves. I was just short half my gears. My father is a transmisison mechanic (lucky for me) and his theorizing led us to believe that perhaps the main bearing was having trauma and forcing the internals backward under load. Monday morning I drove the car to his shop (again using 2nd and 4th). His test drive gave the same results, namely popping out of 1st and 3rd, and no 5th gear at all (would not engage). Four bellhousing bolts, a driveshaft, speedometer, shifter, starter and tranny mount removed, then out it came. Easy 10-15 minutes of work, plus its so nice to have lifts. Also helps that I've done this two or three times before on the same car. So, transmission out and over to the teardown bench. A pin, bolt, spring and cup , a few snap rings as well as some long bolts out of the middle and the thing splits in two. Visual inspection shows nothing unusual. Fluid looked just fine. Sure, there was a little bit of goop in the shifter receptacle, but the gears look good too, no abnormal wear whatsoever. No severe slop in any of the bearings, or excess play in the gears at all. We shifted it through each gear manually on the bench and couldn't hear any odd noises in any of them, or find difficulties in shifting. The only real wear was on the teeth that engage 5th, they were a little rounded on the edges, but not seriously at all. Hmm... New theory: something must be up with the shifter (I have the MSA short shift kit installed). Went to remove the fork on the end of the rod that attaches to the shifter bucket (inside the output side housing), but the bolt won't budge. We give up and decide to put the washers and nut back on the bolt, but drop one of the washers inside the housing. Fishing around with the magnet yeilded zero results, so time came to manhandle the thing until it relinquished its hold on my washer. Tink! I hear. "Oh good", I think, "my washer and I are reunited once more." Nope, it was a little tiny screw that fell out onto the teardown bench. Guess where it fell out from... Yep, the shifter housing on the backside of the transmission. Oh, I did get my washer back too. The previous owner had neglected to install a dust boot, or even the rubber shift boot on the car, just the leatherette shifter boot on the inside of the car. Someone else must have knocked the thing down in there in the past where it was floating happily until my spirited driving awoke the ancient spirits which abode therein. The spirits of the tiny screw were angered by my displays of cornering G's and flung the tiny screw behind the shifter receptacle. That explained why I didn't have any gears that involved a forward throw. Here's a picture of the angry little fellow: Concluding what might now be an essay, I threw the case halves in the parts washer. Reassembly went smoothly now that it was sparkling clean. I made double sure to tighten the zip tie on my dust boot when I had the tranny and shifter in the car again. Back in the car it performed flawlessly much to my amusement. I'm also performing some other maintenance on the car this week, but soon I think I'll have most of those pesky deamons excised from my vehicle. Then it'll be back to high G nirvana for me and the Z. You can chose a moral to this story: A. Don't trust the P/O's workmanship too much. B. Demons may sometimes be expensive or frustrating to find, but if you don't push the car they'll mount a sneak attack when you're least expecting it. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 22, 2008 Share Posted August 22, 2008 Lucky you, my angry little bolt ended up in my U-joint in the steering column and locked up my steering wheel...while I was driving. Damn near killed myself and the car. Good find. Quote Link to comment Share on other sites More sharing options...
Careless Posted August 22, 2008 Share Posted August 22, 2008 I remember that post, cygnusx1. it was definitely a huge surprise when you posted the verdict. Quote Link to comment Share on other sites More sharing options...
woldson Posted August 22, 2008 Share Posted August 22, 2008 CandC, somehow.... Blue72 that is a great and detailed information added to myself and this site. Quote Link to comment Share on other sites More sharing options...
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