Tigue710

Hey everyone, So I got me a 95 4runner v6 3.0 Auto Tran. money pit, I think... I paid a good low price and I'm expecting to put some money in it, but I think I might have a lemon on my hands... besides everything else that needs to be done, I have an interesting vibration, associated with a humming noise...

This is what I have, when under load, at 3000 rpm's, 40-55 and 70-80, or when in park or neutral, sitting still not moving there is a low pitch huming sound and a very slight vibration which I feel mostly in the pedal. Its not loud, just noticeable. Again even when the truck is not moving I get it at 3000 RPM's. Below that there is no noise, above that it either sometimes goes away or other times continues...

I'm afraid of catastrophic engine failure here, lower bearings...

Anyone have any ideas?

Thanks for checking out my post...

BamaYota1

Kind of sounds like transmission pump to me, but you should also rule out anything belt driven, like power steering pump or a/c.

Pure guesses but you have to start somewhere.

BamaYota1

Any idea when timing belt was last changed? Could be idler pulley.

Tigue710

this puppy needs just about everything, I've been going through it, started with front brakes, shock absorbers and packing the bearings, brakes were metal to metal and had to be done so did the other stuff while I was there...

All the belts need to be replaced and there is whinging noise coming from a pulley or belt...

The tran. is slipping in 1st a little, roaring hesitation to engage - would the noise still be coming from the tran. in park/neutral?

I loose power and can not get the truck above 3000 rpms under load, petal to the floor, (up-hill) even though I'm going 70-80 on the highway.

The timing is at 13, needs to be set back to 10

I'm not sure about the timing belt and when it was done last. odometer reads 250, sticker says it was done at 185 - previous owner said there was a new motor put in, (new or pick and pulled? IDK) at 170. The fan housing was possibly replaced when the radiator was done by previous owner a few months ago.. (new used radiator, sticker is on fan housing, not on timing cover as usual), after a small fender bender... (as i type this and put two and two together I realize that it makes no sense, not to mention I see no evidence of the motor having been replaced) Engine sounds great in idle, and under 40...

rworegon

Cracked flex plate?

BamaYota1

Pump still works in neutral and park, the rest of the tranny is not engaged. If you are slipping in first, you definitely have a tranny problem. Most tranny's start slipping in the higher gears first when it is clutch pack related. My money's on pump. Of course, when you pull it, you had might as well rebuild the clutch packs while it is open. Have you dropped the tranny pan to check the filter? I haven't been inside a Toyota auto, but a Chevy with a blocked filter would start slipping and eventually burn up the pump. There's a chance you could get lucky and it is not toast yet.

If you are not sure about the timing belt, I would change it. While you are in there, you can check out all the timing belt components.

Tigue710

thanks for replies everyone. I'm going to pick up a parts truck or another project today, got one with a blown head gasket that was supposedly running great besides that...

No one thinks I might have a bad lower end judging from this noise and vibration? I dont want to do timing, transmission work with a motor on the way out. It sounds a lot like a Chevy 350 I had sounded when the crank shaft bearings went...

BamaYota1

I guess it could be. It is very hard to diagnose vehicle noises over the internet. You could always pull the pan and give the bearings a look. Wouldn't hurt to see what you are working with anyway.

Tigue710

looks like the transmission is the culprit, not shifting into 4th, bad valve, other issues... not quite sure exactly whats causing the vibration but its the in the Trans...

thanks everyone, looks like I have a good motor, if you like 3.0's

Tigue710

WOW! So I want to follow up on this post, I cant believe what it turned out to be. After taking the truck to a mechanic he told me the engine is fine, but the transmission is not engaging in 4th gear and making the noise and vibration. He noted the shift cable from the throttle body had been tampered with. After thinking about this I looked into why the guy I bought the truck from would adjust this cable, and couldn't find a reasonable answer. After inspection I noticed all the cables into the throttle body, (Trans., Cruise and throttle), had been adjusted. I figured he was trying to hide a bad idle, but there isn't one... my idle is high, around 1200, so I decided to set it back to where it belongs, and adjust the trans. cable to where it belongs in the process. I still couldn't figure out why the accelerator pedal was flooring out so quickly so I checked to see if my adjustments had corrected it, they didn't. When I checked the pedal itself I found the culprit... A little rubber grommet that cushions the pedal on the throttle cable was cracked and half broken off, a small 5 dollar rubber grommet... This made excessive play in the pedal, half the pressure put on the pedal was not moving the cable at all! The guy I bought it from must have adjusted all the cables on the throttle body trying to correct the loss of power... I'll say it again, wow! And the high idle? a little adjustment to the DP, and readjusting the throttle cable...

Going over this truck all the things I'm finding that were done incorrectly is just blowing me away..
But hey, I got my power back, I got 4th gear back, and after driving a while the noise has gone away as the Trans. corrects itself... So good Transmission, good engine, good everything... cracked, split and broken tiny little rubber grommet...

timing is good to now...

I hope I at least caught it and corrected it without any major damage being done before I bought the truck...