Latest victim of the 348 gearbox curse

Any time my man, any time at all. I'm glad that I can be of help.

 

+1!!

 

Get a room!






(er, I mean, +1...)

 

Um.... how do I say this? I think the bug has bit '86426'.

Humming sound(?) when clutch is released; sounds fine when clutch is depressed. Car is parked in the garage, and I have no interest in driving/worrying about it for a while. I actually have a line on a 0-miles 1994 348 'thin splined' box, that I'm half tempted to install and just toss the old one into the dumpster.

Nonetheless, I'll just patiently wait until the box can be properly diagnosed rather than do something stupid like try to "drive through the problem".

 

Could just be the throwout bearing (or just a worn spot on the flywheel). I wouldn't panic yet.



But if you (or anyone else) would like to sell a broken 348 gearbox, it's worth $1.5k shipped to me "as is." I collect spares proactively.

 

Daniel,

Was it a rumor that your clutch shaft is kinda buggered and patched? If yes then look here for play in the clutch shaft gear. Use some heat and pull out the clutch shaft out of the box.

 

Daniel, since based on your coment about just buying the new gearbox, go ahead, just drive it. Siince this happend after you had the oil changed, chance it again, and see if there it any metal in it. I hear sawdust works great..it's only money, it's the fun and time you cannot get back.

 

The clutch shaft is brand new (ok, basically brand new... it was installed 1500 miles ago). I'm thinking it's those damn bearings on the side of the case.

 

Geezz. Sorry man. At least your in the biz. Fix it when you can.

 

More data needed to diagnose. If it is the side bearings and only 1500 miles ago then the rings were not torqued down enough and or you need to stake the rings so they can't back out. And I mean actually breaking the metal lip into the shaft land. In fact see Micheal B's picture of the smashed lip. That's the way to do it but you should have the proper tool to tighten the ring nuts. A hammer and chisel won't work.

 

That is what I'm thinking too.

Sorry to hear about your problem. I DO NOT recommend you driving it, as you well know how expensive it can get for the gears, especially the ring and pinion gears. Drain out the gear box oil and check for bits, then pull the inspection plate and look for damage.

But now that I think about it, didn't you just have this thing "fixed" a few months ago??????????

If you are gonna put in a new box why not just slap in a 6 speed like Andy?

 

One more data point.... with the car standing still in the garage and the engine running, the sound is audible when the clutch is released and the car is just sitting out of gear. Depressing the clutch, even with the tip of my toe about 1mm, the sound disappears. In both instances, the car remains out of gear.

It's interesting to hear the varied responses. Some think TO bearing, others say it's the side loaded bearings. Of course we can't really know anything until it's apart, but it's curious to see different theories.

 

I say it's that damn oil pump bearing again. Bets, bets, bets anyone?

Wanna know why? Because when you depress the clutch it disengages the the gears from the output shaft. Even when the car is in neutral the gears will still turn inside the gearbox when the clutch is engaged. Dan DO NOT even turn it on, again DO NOT TURN THE CAR ON. You may get lucky and only have to replace the bearing/s. But the last thing you wanna do is have the main shaft moving around while the engine is running. The only way you are gonna keep the gears from turning inside is if you are sitting in the car the entire time with the clutch in. Like I said, even when it is in neutral the gears are turning inside the gearbox. When they are turning the noise you are hearing is from the screwed up bearing, and from the gears not meshing properly because the main shaft is moving around. If you have any bits of the bearing cage that get past the little plastic oil filter they can get sucked up into the gearing and wreak havoc. Then the sychro rings and cups can get worn because of the shaft moving also. DO NOT TURN THE CAR ON!

Drain the oil, and pull the inspection plate on the bottom.

 

Ah grasshopper... what about the fact that only 1mm of pedal push causes the noise to stop? I wouldn't have thought it could disengage the transmission with such little pressure, but only load the hydraulics on the TO bearing.


p.s. Don't worry - the car isn't being started or driven. Stuff doesn't magically fix itself with a hard drive around the neighborhood.

 

I thought you were pushing the peddle all the way in? I missed the 1mm part. So what you are saying is, if you just touch the pedal, not push it in all the way, the noise goes away? Just barely putting pressure stops the noise? Then if that is the case, the peapod in the jar winner is No Doubt. I would have a serious look at the throw out bearing, and if that checks I would drain the oil and pull the inspection plate.

I just cannot believe that the shop didn't take a look at these things when they had it apart.

Whatever the case, something is wrong.

 

my guess, throw out bearing or maybe a carrier bearing at the flywheel or
something like that.
I think once you put a little force on the clutch assembly etc it loads up one
of those bearing and stops the noise.
just a guess from not listening to it.

 

I didn't read the entire thread but...

Why would a burnout cause problems? I don't see why a burnout would cause any extra stress over a strong launch. When the tires break traction there is less resistance on the parts that when there is hard acceleration with traction... so I don't get it? Maybe its the hard clutch drop that would accompany the burnout, but a no burnout launch would probably have the same effect on the parts. Thoughts?

Gene

 

throw out bearing or pressure plate fingers. My vote is pressure plate fingers. They rattle then stop with light T/O bearing pressure. Look for groves in the fingers and broken fingers or spring. I have seen damage to this system when the entire pumpkin with guts is put on the shafts as 99% of people do. I have always advocated placing flywheel assembly on shaft then belhouse on end bearing then torqueing the large nut in place once the bellhouse is fully seated. If people reading this have no idea what I am talking about I bet they place the assembly on as one unit. Most people do it as one unit because they lack the airtools and the tool to tighten the castle nut. The reason this is a problem is because that sucker is heavy and it is hard to passively get everything to line up and slide on without cocking and damaging something. I have fixed other peoples problems from this.

 

Really Bob? Holy moly.

I never thought of doing that but it makes sense.

When I had my clutch pack renewed the place that did it insisted that I send them the whole pumpkin – untouched - because they were sure that no one on earth could take it apart & put it together correctly if they were to just send parts. Their thoughts were that if they were to just send their parts (and not assemble them into one complete unit) that they would/could be blamed if something did not go together correctly.

I said to them in so many words: Look, I am able to do this; I am not sending you my whole thing just so you get a warm fuzzy feeling. Then I proceeded to persuade them to send just the clutch pack.

Anyhow, my point is, they do not even give you an option as they wanted the whole thing installed as one unit without any end user disassembly. Period. That was the only way they would guarantee it to any bloke off the street.

I did not give a hoot so I did it my way, but others would not be allowed to do it your way.

Hey, I sent you an email a while back to your yahoo. I got it figured out.