Gearbox Issues?

[mint 61]

61 Series 2. Installed a new clutch and flywheel last summer. Worked great for about 350-400 miles.
Then a few weeks ago during my 3rd cruise this season, it suddenly started to lose power. Like a clutch slipping. Only made it a 1/4 mile down the street and turned around, barely had enough power to get up my driveway. Then I pulled it out a little later to diagnose and lost all power to the wheels. Wouldn't go anywhere. It's only got 35k on it, so I wouldn't think the gearbox would be bad so suddenly. It shifts perfectly, no problems going into or out of gear. Thought the clutch may been stuck engaged, but if I try to shift into gear when off the clutch pedal, it grinds as if the clutch is working fine. Push the clutch, goes into gear, let off the clutch, nothing but a very slight whirring from the gearbox area. I confirmed the driveshaft does turn when off the clutch, but not sure if it's turning when under load. Got it on jack stands and pulled the gearbox and clutch, everything looks to be OK there. Rebuilt the slave and master not too long ago, it seems to be working fine. When you manually turn the rear wheel, it turns the drives hast when in neutral, but not sure about under load. When I manually turn the gearbox it spins on both ends. Haven't opened the gearbox to look inside yet.
Any ideas what could be going on here? Maybe something wrong in the rear end?
Any ideas? Happy to provide more info if needed.
TIA

 

[sunalp]

Don't think you have a trans issue. They don't suddenly go bad. Sounds like a clutch issue. How is the pressure plate?
How does the flywheel look? How tight are the flywheel bolts? Could be something like that , but my money would be
on the pressure plate not allowing the clutch to disengage.

 

[jumpinjan]

Where did you get the parts and are they the correct parts? What was wrong with the flywheel? No need to replace it, it only needs a resurfacing, if at all!
I would put the old clutch & flywheel back in with a new clutch disk.
Jan

 

[mint 61]

Sorry I should restate that, new gear ring on the old flywheel. Got the new clutch from Rickk at SS.

 

[mint 61]

Down here looking at it and remembered that when I took it all back apart there was one flywheel bolt that loosened by hand. Wondering if it could have back out enough on its own to create space between that clutch disk and flywheel, explains why it happened relatively suddenly. Also wondering if it's possible to put the clutch disk in backwards!

 

[jumpinjan]

Also wondering if it's possible to put the clutch disk in backwards!

Normally no...but installed backwards, it would make one hell-of-a-lot-of-noise!!!....I would think.
You better get some locktite on those flywheel bolts! I always do that.
Get the old pressure plate and do some measuring & comparing with the new one.
Jan

 

[mint 61]

Ok, not in backwards, it would hit the flywheel bolts. Just got done reinstalling the gearbox. Everything looks kosher in there.

 

[sunalp]

You can put them in backwards, the clutch won't work at all. Doesn't really make a lot of
noise, just won't work. The bolts won't allow the pressure plate to work.
Definitely check the pressure plate.

 

[mint 61]

Don't think that was it, worked perfectly for 350 miles, then pretty suddenly...it didn't.

 

[puff4]

Busted clutch pressure plate diaphragm?

 

[mxp01]

I had similar problem happen to me while driving the exact way you describe it. You say the drive shaft spins when in gear but the cars wheels won’t move. Do you have the car on jackstands or the ground? For me the drive shaft spun while sitting on the ground and the car wouldn’t move.

Turned out I had a stripped axle key on the right axle. All the symptoms of a worn clutch MINUS the spinning drive shaft.

put the rear up on a jack, put the car in 1st gear and try to spin each wheel. I had to put some muscle into, but I could get the right side to spin.

 

[mint 61]

Interesting. I'll have to check that out, getting it put back together now. I've had a little chatter on the rear drivers side wheel when almost stopped. Figured it was a sticky caliper or something. Thanks for the heads up.

 

[mint 61]

Update, we've got it back together and everything works fine! All I can figure that it was that flywheel bolt had backed out enough to keep the clutch disk off the flywheel. I'm rolling again! Thanks for all of your help, this forum is very valuable.

 

[hartmandm]

Did you find a score mark on the clutch disc where the bolt head would have been making contact?

 

[mint 61]

Did you find a score mark on the clutch disc where the bolt head would have been making contact?

Negative. Here's a picture.

 

[hartmandm]

I'm not following how a flywheel bolt could back out enough to make contact with the clutch disc, but not leave any marks on that disc, given the flywheel is spinning while the clutch disc is stationary.

My series V has retainers on the flywheel bolts. Not sure if the series 2 setup had those as well.



Mike

 

[mint 61]

Yes, the S2 has the same retainers. I remember the retainer still being on, but being able to loosen 1 bolt with my fingers. I think that bolt would have to be a good ways out to hit the plate, and i think i would have noticed that. I'm stumped. As you can see in the pics the clutch looked fine. Hopefully it doesn't happen again.

 

[Jay Laifman]

That is pretty weird. I don't see how it fixes itself. It does sort of sound like the clutch wasn't maintaining pressure on the disk, or disk failure. But I'd think we'd seem some obvious friction overheating on the disk, or total damage to the center, if it was.

I've had an axle shaft go on a car, and had lack of power. But as you pointed out, you were able to shift between gears. So that wouldn't be it.

I'm wondering if the throw out bearing arm is getting interference somehow. And it is stopping the TOB pushing all the way forward. Now that you pulled it all apart and put together, maybe whatever it was got pushed out of the way. But unless there was something obvious, I would think that it will come back again.

 

[Scotty]

Is it possible that your Carb isn’t set right and you’re losing power due to low RPMs? What is your idle RPM?

 

[Jay Laifman]

You know, that's a good point. You said you "lost power." You didn't say your rpms spun up - which is what would have happened if any of these clutch/TOB/Axle theories were true. What fuel pump are you using? Mechanical or electric? Could it have quit? How clean are your gas tanks?

maybe you have just enough flow to keep idle and low rpm, but not drive.

or your distributor advance is sticking.