clutch problems, help with diagnosis

[Dreco]

hey all, got a problem shifting into second gear.. it grinds going in from 1st, or downshifting from 3rd. it always felt like there wasnt enough throw in the hydraulic system to disengauge the clutch fully... well, I pulled the transmission(1981 280ZX 5speed non turbo) to take a look see. and I found that a few of my pressure plate bolts had come loose (I have a centerforce 2 clutch)..about 3-4 turns to snug.

It made me think that maybe because of this, my clutch was draging a bit, especially with those centrifical weights.. well, I tightened everything back up, but the transmission back on, replaced the master and slave cylinder, bled the system, I have the right year clutch with collar, and it still does it..although not as bad.

It worked fine for the past year or so. This is something that's just happend one day at the track and got worse. It just started grinding one day.. I can get it not grind by pulling out of first, waiting a split second, then go to second, but that could be from the RPMs meshing better. this transmission has been rebuilt before, but I'm starting to question how well.. has anyone had this experience before?? BTW, it doesn't grind at all going into reverse, although before I tore everthing apart it did grind sometimes.

also, should the throwout bearing be touching the pressure plate spring at all when the clutch pedal is out?? cause to get this to work, I had to adjust it like that.. which is why i'm thinking the clutch and or plate is bad,

let me know if you all need more info..

[240ZMan]

Here is what I think happened: once the bolts on the pressure plate backed out, the clutch no longer fully disengaged. This put a lot more load on the syncros when shifting and I'll guess your 2nd gear syncro is now worn (which is usually the first to go). Now that you've fixed your clutch, the problem remains because the syncro is still worn.

I think you either rebuild the tranny again, or granny shift.

[Dreco]

Here is what I think happened: once the bolts on the pressure plate backed out, the clutch no longer fully disengaged. This put a lot more load on the syncros when shifting and I'll guess your 2nd gear syncro is now worn (which is usually the first to go). Now that you've fixed your clutch, the problem remains because the syncro is still worn.

I think you either rebuild the tranny again, or granny shift.

that's kind of what i'm afraid of... well, my friend still has my older 4 speed.. when I get that back.. I think I'll throw it in and see if that doesnt fix the problem... I know that tranny works. and I'd like to be certain before I spend any money. I'm just not looking forward to playing musical transmissions... :hurt:

[240ZMan]

'm just not looking forward to playing musical transmissions... :hurt:

If it's any consolation, I bought my 5 speed used, found out the 2nd and 3rd gear syncros were shot, had it rebuilt, put it back in, found out he didn't get it right and syncros still worn, reinstalled, found out he goofed on reverse and it wouldn't stay in gear, pulled it again for repairs, and then finally (touch wood) reinstalled it. By the fourth time I was pretty good at it. :mad:

[jmortensen]

When I had a clutch slave go out the symptoms were similar. Started grinding on upshifts, then started having trouble putting it into reverse at all. It was driveable at first and I was thinking about synchros, then on the 3rd day it just blew out entirely and wasn't driveable anymore.

You might just check the master and slave by pulling the boots off and see if there is any fluid under the boot. If so, that's your problem. Easy to check, and could be related to the symptoms you're experiencing.

You don't want the clutch adjusted out so that the throwout bearing is always in contact with the pp, as this will wear the throwout bearing out rather quickly.

[Dreco]

If it's any consolation, I bought my 5 speed used, found out the 2nd and 3rd gear syncros were shot, had it rebuilt, put it back in, found out he didn't get it right and syncros still worn, reinstalled, found out he goofed on reverse and it wouldn't stay in gear, pulled it again for repairs, and then finally (touch wood) reinstalled it. By the fourth time I was pretty good at it. :mad:

oh, I can do it pretty quick now.. I've done this a few times. It takes me longer to get to the drive shaft bolts than it does to take the tranny out now haha... I just hate layin under that tranny and wresling it...

[Dreco]

When I had a clutch slave go out the symptoms were similar. Started grinding on upshifts, then started having trouble putting it into reverse at all. It was driveable at first and I was thinking about synchros, then on the 3rd day it just blew out entirely and wasn't driveable anymore.

You might just check the master and slave by pulling the boots off and see if there is any fluid under the boot. If so, that's your problem. Easy to check, and could be related to the symptoms you're experiencing.

You don't want the clutch adjusted out so that the throwout bearing is always in contact with the pp, as this will wear the throwout bearing out rather quickly.

well, I installed a new master and slave cylinder... I had someone push the clutch while watching the fork.. that part is working fine now, .. it goes into second.. just grinds sometimes.. my gut is telling me tranny.. cause thats the most expensive problem hhahaha

[240ZMan]

I just hate layin under that tranny and wresling it...

Use your floor jack.

[Dreco]

Use your floor jack.

well, it's actually faster not using that.. I had an incedent were it roll off that damn thing and smashed the hell out of my finger...it's still not right haha... I'm 5'10 205lbs and bench 265... I just bench it out of there while wearing a cup hahaha

[Chris240turbo]

Dreco, we met at the ZCON this year, I have the smurf blue turbo 240z, I've rebuilt a couple B boxes like yours, and have my 35'x30' shop nearly completed, I also have an MSA short shifter for a B trans that I'd sell, I'm going to go with an SX trans, as my car has blown up 4 early transmissions over the last few years, if you'd like bring it by and we'll crack it open and see what's what, I live on the NW side of FTW, near 820 and 20

Chris, 817-448-9265

[Dreco]

Dreco, we met at the ZCON this year, I have the smurf blue turbo 240z, I've rebuilt a couple B boxes like yours, and have my 35'x30' shop nearly completed, I also have an MSA short shifter for a B trans that I'd sell, I'm going to go with an SX trans, as my car has blown up 4 early transmissions over the last few years, if you'd like bring it by and we'll crack it open and see what's what, I live on the NW side of FTW, near 820 and 20

Chris, 817-448-9265

PM sent

[Ed]

Does anyone have a picture of the tranny all torn apart? What does the syncro look like?