Knocking sound engine or tranny? Take a listen. 2.4L.

Hi yall' Newbie to the forum, so I want to say hello to everybody!

2000 tacoma owner here. Truck is a 2.4L, 2wd 5 speed 98,000 miles, and I was wondering if some people on the forum could take a listen to this sound and possibly tell me what it is..

I've heard that it could be a input shaft bearing or it could be something else like a rod knock??

I'm sick to my stomach worried about it..

You can view/hear the knock here.. Thanks, in advance!

http://www.youtube.com/watch?v=8ENhHu3hxL4&feature=youtu.be

 

Sounds like an exhaust leak.

 

I should be so lucky! I can feel it through the pedal and the shifter.

 

Doubt its a rod, it may be one or more of the fingers on pressure plate that are bent or breaking, any slippage from disc ?

 

No slippage. Tranny seems to shift just fine, and no noticable shutter like you would get if the clutch is worn. I believe it's original..

Truck runs really good other than the noise. I read somewhere you can test for a rod knock by disconnecting the spark plug wires one at a time and see if you still get the sound in that particular cylinder. I tried that to no avail. I guess the motor in these automatically shuts off when the computer senses it's running on three cyl. Then the check engine light came on for a bit but went off after a little while of being hooked back up.

 

Well whatever i'm hearing isn't dull & low pitched in sound like a rod or some other bearing , might be a belt even

 

Can you do any mechanical work to repair your Tacoma or would you go to a mechanic ? If you have 4 jackstands, you need to jack up your taco and place them under the frame to hold up the truck or go to a lift. You need to get under and investigate this noise as it happens. I believe you have an exhaust leak and you may have bad motor or transmisssion mounts. This is allowing your motor to move and make your vibration in the pedals. Your noise could be a bad front U joint or the transmission mount is broken and causing a binding on the U joint.
I could be totally wrong, but you need to investigate this further by getting closer to the problem under the Taco.

GOOD LUCK AND WELCOME TO THE FORUM.

 

I'm pretty handy and do most things myself, but I have never done a clutch and I live in a small apt complex with nowhere to work on it without getting bitched at by management, so probably take it in.

I found this video. Sounds just like this.. http://www.youtube.com/watch?v=r1So1PAsf-U

 

So I think the problem is finally solved! I took it in to some local toyota pro's and had them take a listen. The main mechanic said the sound was concerning for sure..

He initially thought it might be carbon on the pistons so he did an inspection, I guess with a small camera of some sort. The result was that the pistons were clean, almost too clean in his opinion. (I had ran a bottle of b12 chemtool gas additive a few days prior so maybe that helped) He said they were nearly shiny.

He suspected that somebody may have been in there to try to fix the problem and failed before I bought the truck.

So they proceeded to track down the sound to the front of the motor, I believe cyl #1 and was somehow able to bypass the computer and pull the spark wire for that cyl, and low and behold the sound diminished quite a bit. I was very nervous to say the least.

They pulled the pan and inspected the rod bearings and all of them were original toyota, and the pan had never been off since new.

He said the connecting rod bearings looked brand new, and thought that someone must have replaced them, but upon further inspection, found that the truck had been meticulously maintained, but for some reason, the upper front main bearing had considerable wear.

He deduced that the one bearing on top had gone bad probably from someone over-tightening the drive belt, putting too much pressure on that one particular bearing.

I did a little research and sure enough, this is known to happen from time to time to that particular bearing.

He even seemed somewhat surprised that even that little bit you could BARELY (if at all) even feel with your finger nail, was enough to cause the sound I was hearing, but it now appears that is the case.

So, after a new upper main bearing put in, the truck seems to run like brand new!

So I know from searching that there is a thousand random 'knock' threads like mine with NO solution. I'm happy to say that (knock on wood) my problem seems to have been fixed!

Thanks for the input everybody!