3rd gen 5spd tranny with power in nuetral?

[bflooks]

hey guys...

1998 4runner, 3rz, 5spd, 200k miles, newly sas'ed.

problem is that after the sas, with the rear end in the air and the tranny in neutral, the rear wheels still have power to them. if you grab hold real good on the tires, they stop. i can hear a bit of a chirping sound coming somewhere from the tranny area with the ebrake on and the truck in neutral. i have never heard of or seen this.

idea's?

i did have the clutch pedal push rod adjusted a while back from toyota when (what turned out to be a bad friction disc) the clutch wouldn't engage correctly. could this cause the tranny to still put power to the rear wheels, even if it is in nuetral?

[p nut]

It's pretty normal. The oil is still cold and the clutch plates are still meshing which makes the wheels go round and round. It should stop once the rig is warmed up.

[20005spd]

this is normal. any manual trans vehicle will do this with the drive wheels in the air, trans in neutral. with clutch pedal released the engine is still turning the transmission. even though it isnt in gear the friction inside is just enough to get the wheels to spin.

[20005spd]

the chirping sound you hear in neutral ebrake on is from a brearing in the trans. my trans has been doing this same thing for quite a while now, slowly getting worse. didnt you change transmission when sasing?

[bflooks]

i didn't change the tranny out when sas'ing. i have the original tranny from the truck that i may just slap back in when i do the dual cases i suppose. the one that is in it now is cody's old one with unknown miles on it. my original only had 170k or so on it.

i also have a throwout bearing going bad, but i am not worrying about that until i decided if i am swapping trannies or not.

[20005spd]

whats wrong with the throw out bearing?

[JWBehm]

Yeah I have the high pitched squealing, thought it was the throwout bearing but it is the pilot bearing.

[bflooks]

if it is the pilot bearing, i am not going to be swapping that out until the next time i do a clutch. i am 99% sure it is the throwout bearing though because it goes away by stepping on the clutch.

[20005spd]

if it is the pilot bearing, i am not going to be swapping that out until the next time i do a clutch. i am 99% sure it is the throwout bearing though because it goes away by stepping on the clutch.
the throwout bearing does not spin until the clutch pedal is pushed down. so if that bearing was noisey then it would only make noise with the pedal down. so your noise is just like mine, its either the pilot bearing or a trans bearing.

[bflooks]

that is interesting then. the last time i had the same noise, it was the same way. i could have sworn i was told on "another" forum it was the throwout. regardless, neither is getting swapped until i change trannies or do a clutch. it's just not worth it to me. i'll deal with the noise.

[Ian Rogers]

The pilot bearing is not spinning when the clutch peddle is not depressed. It will not make noise unless is is spining.

The throwout is spinning most of the time. it will normally will make noise when the clutch peddle is not depressed, and will either change pitch or stop making noise once the peddle is depressed.

[BruceTS]

The pilot bearing is not spinning when the clutch peddle is not depressed. It will not make noise unless is is spining.

The throwout is spinning most of the time. it will normally will make noise when the clutch peddle is not depressed, and will either change pitch or stop making noise once the peddle is depressed.


Have to agree.... 99% of the time it'll be the throwout bearing.

[bflooks]

thanks guys. i appreciate you confirming i was not insane. haha! i was sort of wondering how i read so much wrong information on another site and how everyone else i have spoken to have said the same thing i posted.

[20005spd]

The pilot bearing is not spinning when the clutch peddle is not depressed. It will not make noise unless is is spining.

The throwout is spinning most of the time. it will normally will make noise when the clutch peddle is not depressed, and will either change pitch or stop making noise once the peddle is depressed.
your mixing up your bearings. the pilot bearing sits in the flywheel. the tip of the trans input shaft rides in the pilot bearing. if your trans is spinning ,which is does @ idle in neutral, then the pilot is spinning. with the clutch pedal down it stops the trans from spinning and the pilot stops spinning. the only time a throwout bearing spins is when the pedal is pushed down. if it touches at any other time then your clutch pedal is adjusted improperly and will wear out the throwout bearing prematurely. there is always a spec on clutch pedal free play before the throwout bearing actually engages the pressure plate, its usually around an inch.

[BruceTS]

your mixing up your bearings. the pilot bearing sits in the flywheel. the tip of the trans input shaft rides in the pilot bearing. if your trans is spinning ,which is does @ idle in neutral, then the pilot is spinning. with the clutch pedal down it stops the trans from spinning and the pilot stops spinning. the only time a throwout bearing spins is when the pedal is pushed down. if it touches at any other time then your clutch pedal is adjusted improperly and will wear out the throwout bearing prematurely. there is always a spec on clutch pedal free play before the throwout bearing actually engages the pressure plate, its usually around an inch.


Hate to break the news to you.... but your so wrong! :chair: Think about what you wrote :headscratch:..... If the pilot bearing is spinning, that means the input shaft to the transmission is NOT turning at the same rate as the crankshaft. The clutch locks the shaft to prevent it from spinning, thus the pilot bearing remains stationary. When the transmission is in neutral, the input shaft is spinning at the same rate the crankshaft is, provided the clutch isn't depressed :D

Toyota's use a self adjusting clutch slave cylinder, so most of the time the throwout bearing has some sort of contact with the pressure plate. So it will spin slightly when not engaged.

[Ian Rogers]

Thanks Bruce,

I was trying to think about how to put this in words and you did it wonderfully. I would add that the only time the pilot bearing spins with ant rpm's is sitting in 1st gear at a light/stopped most of the other situations where the pilot bearing is in use are during shifts and there is not a huge discrepancy between engin rpm's and input shaft rpm's. A lot of old Chevy's use a brass pilot bushing in place of a bearing. All the pilot bearing dose is keep the input shaft in line with the crank when the clutch is not engaged.

[20005spd]

woops, i do stand corrected (partly). your right about the pilot bearing. i just said the opposite of what it should be. but the throw out bearing should not contact the pressure plate unless you have the pedal down. there is no ifs ands or buts about that one. and even if it somehow does slightly touch the pressure plate with the pedal up, then why would the noise go away when the pedal is actually pushed down. it should get worse in that case. which brings me back to one of my original posts


the chirping sound you hear in neutral ebrake on is from a bearing in the trans. my trans has been doing this same thing for quite a while now, slowly getting worse. didnt you change transmission when sasing?

[BruceTS]

The way the throwout bearing operates is similar to how brake pads back away from the disc after being depressed. There's no return springs, just the disc that kicks the pads away, but there is still slight rubbing, yet you don't hear the pads dragging while driving. The pressure plate acts in a similar fashion, kicking the throwout bearing back, but it still makes a tad bit of contact, unlike the older design, that needed to be manually adjusted as the friction disc wore down.


As for why the bearing makes noise, then goes away is quite simple...... the grease is dried out, so them little balls can rattle in the race. Depress the clutch and the pressure applied to the balls quiets them down. I've experienced this many times in the past, replace the bearing and the noise is gone.......

[Ian Rogers]

but the throw out bearing should not contact the pressure plate unless you have the pedal down. there is no ifs ands or buts about that one.

I think you are thinking about an older truck like my FJ40 it has a return spring on the clutch fork that pulls T/O bearing away from the Pressure plate. With this design i have to adjust the clutch about every 30,000 miles to get the engagement back to spec.

and even if it somehow does slightly touch the pressure plate with the pedal up, then why would the noise go away when the pedal is actually pushed down. it should get worse in that case. which brings me back to one of my original posts


The sound changes because as the force is applied to the bearing it is forced internally into a different section of the bearing race, that may be in better shape and not make noise.

[/quote]

[bflooks]

so i am sad to announce that i got stranded last night on the highway. i was just getting on to the highway, shifting in to 3rd (no more than 3500rpm at the time), and i heard a ruckus, felt a pop/bang, and... NOTHING! no gears at all. the motor is still running strong, i can't put the truck in to any gear without using the clutch, and when i do put it in to gear, as soon as the clutch catches, you can feel movement in the stick, a very very slight push on the truck and then absolutely nothing. the engine is free revving and the noise/feeling in shifter stops.

we are diagnosing tonight if it is the tcase, tranny, or if i somehow grenaded a friction disc in the clutch. dual cases were going in, and i have a spare tranny with 170k on it, so that is no big deal, but i didn't expect to have to get in to this job... again! i just replaced the clutch about 35k miles ago back in march of last year. :(

anyone ever hear of this or experience anything like this?

[bflooks]

forgot to post up the outcome. the center part of the friction disc separated from the rest of the disc. not sure how in the hell that happened, but that is what it was. it now has a marlin clutch kit in it, new flywheel, and my original tranny back in it. i just picked up a dd so the truck will not be driven much anymore (average about 30k a year on it) except for the snowy commutes and for trail runs, so hopefully this clutch will last 5 or 6 years.