Mysterious drivetrain sound (2)

[tonyg2781]

Hey Guys and Gals,

I posted this on the general discussion but it looks like this section of the forum is a bit more technical. You guys have any ideas?
I have a unique situation on my 2000 4Runner SR5(automatic). I want to preface this inquiry by noting that i have had a radiator blow which caused water contamination in the tranny. I flushed it by removing the return line (recommended by trans tech) and running about 20 quarts through it. The fluid looks just fine, The transmission shifts just fine and there is no slippage.

Upon acceleration from a stop, there is a "fluttering" sound, kind of like baseball cards in a bicycle spoke until 30 mph is hit, which is right about when the tranny shifts into 3rd. I can actually feel a bit of feedback of this in the accelerator pedal. When approaching 30 mph (around 25 mph or so) the sound cuts out once or twice and then goes away. The sound never returns again until the vehicle falls under 30 mph, and it only occurs when the vehicle is in drive and the vehicle is under accerelation.

I think that it is either a issue with a clutch or something with the driveshaft. I am pretty experienced working on my own vehicles and worked in a body shop for quite some time. This one has me stumped.

Has anyone experienced this or have any ideas?

Thank you in advance,

Tony

 

[4RunnerDNA]

Is your runner a 2WD or 4WD? I had a noise in similar situations which turned into a chirp, turned out to be a ujoint. If its 4WD get under your truck and grease all the zerks.

 

[tonyg2781]

It is a 4WD - A u-joint has crossed my mind- i will take your advice and give that a shot--

Thanks!

 

[4wheeln98]

I think Im hearing that sound too. Its about 1700-2100 RPM. Heard it alot when doing beach driving since it stayed in that range. My friend said it might be something with the air intake.

 

[tonyg2781]

I have greased all the zerks and unfortunately the noise still perists. When going up a slight incline, like a driveway, it really makes the noise and then i put it in neutral and coasted backwards and I could hear it then too. I will let everyone know if/when i find something else out.