Topic: Gah - transmission noises!

[Plekto]

Okay, I've been a good boy(tm) and done all the right things(5 month old HD MC transmission), but today I have a problem.

Normally the thing makes a bit of drivetrain noise when the clutch is all the way in - a soft whining where I can hear a tiny bit of bearing noise.  It's always done this, so I figure it's normal due to the HD bearings.

Today, though, two blocks from work, it would have a sound like a small vacuum cleaner.  Clutch in, spin up "Whhhhoooooo" and then clutch back out, it would spin down again.  Loud like when your radiator aux fan goes on.  If you have a small Black and Decker hand vacuum or similar, exactly that sound. 

I let it sit for a bit and got some lunch from Trader Joe's (same parking lot where I work) and now it's back to normal.      

I'm totally confused here, as it was almost like a relay or hydraulic problem or similar.  I'm not feeling anything in the transmission itself and there isn't a metallic noise, and it would stop and start at the moment that the clutch would release(very on/off like a switch).  Relays?  Hydraulics?  I can't imagine that it would be the clutch as it only has 5K miles on it(HD MC clutch as well).

[Plekto [OP]]

So I talked to people here in chat and looked online at some transmission diagrams.  It looks like the throwout bearing or pilot bearing on the clutch is having problems.

Sigh.  Is it common for them to last 5 months?   What generally causes problems like this - so that I can keep it from happening again in 5-6 months?

[RN37DD]

normally those bearing well make noise when you are engaging / disengaging the clutch every time. I'd also check that your clutch slave cylinder is tight. check the mounting bolts. and make sure your hydraulics are completely bled. no air. if you can pump it up and things change?? then something is going wrong with you hydraulics. those bearings should last the life of the clutch, if the are quality parts.. toyota

[Plekto [OP]]

Yeah, something's odd.  At first I thought that it was a short with my clutch  override switch and my fan was going into overdrive(like a bad fan clutch).  It makes normal noises now, but for two blocks, it was something just not working right - like 20x louder than normal.(clutch and gears were working fine, too).

I'll keep an eye on it, of course.  If it does it again, I'll get a recording of it if I can.

Is it possible for something to have broken off or chipped/etc and gotten things stuck together?  When I stopped, I put in in neutral and let it idle.  I'd  press the clutch down and there would be this 80db or so sound of something almost fan-like revving up and then when I let the clutch up, it would spin back down.  Like someone was flipping a switch on a box fan on and off.

[Plekto [OP]]

Figured it out.

Clutch goes in.. Shhhthunk whrrrrrrrrrrrrrrr.
Clutch goes out... Whrrrrrr...(spins down).

Problem suddenly was obvious tonight on the way home.  Every time I shifted, my lights dimmed until they nearly went off.  Sure enough, I pressed the clutch override button and the noise came on and stayed on uintil the truck died 20 seconds later. 

The ignition switch had shorted to always on the start position.   So every time I shifted, it would engage the starter and then it would go "WTH?" and spin up to maximum rpms since the engine was already running.    Apparently starters don't like going 2000rpm+ and sound like a throwout bearing going bad when they are forced to.  The high pitched sound like a clutch disk grinding itself at high rpms was the bearings pulverizing themselves.

Course the starter after 20 shifts or so getting home was smouldering, so it's probably also fried or close to it.  For once in my life I'm glad something broke.  At least the W56HD is in fine shape.  $200 I can afford.  $1300... yeah... got my blood pressure a tad high...


One question, though.  Apparently this is a gear-driven model.  What's the chance that it might have damged the gear in the engine that it connects into - or is it always engaged to that gear and the starter has its own internal clutch/etc to engage itself?

[kneedownnate]

You'll want to thoroughly inspect the ring gear on the flywheel to make sure it's not too chewed up.  You'll need to bump the engine around a full rotation to make sure you check the whole thing.

[70 Cam Guy]

The starter gear only engages the flywheel when it's turning over the engine.  The solenoid makes the gear move toward the flywheel teeth when you start the truck.

Another bit, when your battery is low, many times all you hear is that solenoid click but no juice to turn the motor.  Also, contacts in Toyota starters sometimes go bad so all you hear is that click.  I hate doing the starter in my truck... I have to do mine again

One way to inspect your flywheel teeth is to inspect them when your starter is out.  Turn the engine over by hand and check for broken teeth.  I don't know what kind of damage happened to your starter but if it still starts the truck ok then it's probably not too bad.  If it starts making a terrible grinding noise when you try to start the truck, then you know theres a problem.

[Plekto [OP]]

Well, I'll be sure to check that.  It looks like a pretty simple repair otherwise.  The starter seems to work, though it's slow and weak.  I'd guess the windings and bearings inside are nearly shot from the strain, but nothing seems to have siezed up.  It would be nice to only have a small bit of damage to the flywheel so I don't have to pull the thing apart again, because yanking the trans and readjusting the clutch/putting it all back together  is a whole lot of work. 

Oh - any easy way to slowly turn the engine over? 

[RN37DD]

1/2 drive ratchet and socket on the front pulley. even easier if you pull the spark plugs.take it out of gear and put the e brake on.

[Plekto [OP]]

Well they want $128 for a new ignition switch, which seems usurous.(plus what the locksmith gouges of course) I'll find one though, and get the starter, too.  My only  issue is getting this thing to work until my next paycheck.

Currently my *new* startup procedure is:
- Put in neutral(e-brake is always on when I park)
- hit clutch override switch
- hit starter and turn it back manually(return spring and contacts are munged - if I move it back manually, it doesn't go forward again unless I press in a bit as it should be)

Seems to be working for now, but part of me just wants to put a button on the dash that I have to also push to start it ($5, connected in series).  The starter looks a bit tight but doable to remove.  I'll see how badly the thing is chewed up in a week.

Pics of course

The clutch seems to be none the worse for wear.  Thankfully the combined time the starter was running was under two minutes in 24 hours, and maybe 20 shifts before I figured it out.  Not enough to destroy anything I hope.