Greetings everyone! Just registered today but been using this site for awhile and it has great advice.
I have owned by T4R since its birth, bought it at the change of the millenium as my previous 87 bit the dust after 160K miles.
I have been searching but there doesn't seem to be much info on problems or issues with the 5SPD tranny for the 2000 model year. I have been slowly doing mods on mine over the years (very slowly) and have the TRD headers and exhaust and an INJEN intake. Now I am working the suspension and tires. My problem is I had the clutch replaced at 90K mostly to fix a rear main seal oil leak about 3 years ago and within the last couple months (130K) the throwout bearing has started "clicking or chirping" goes away when I slightly depress the clutch. Plus it seems my tranny is starting to whine, only does it noticebly when the truck is decelerating in gear. Any thoughts? Don't know if its the pilot bearing in the flywheel or the front load bearing gear in the tranny starts to whine when the load shifts from acceleration to deceleration.

If it is the tranny and not the rear end, I would change out the transmission fluid and put in some Lucas 90-140W gear oil. It will quite it down.


As for the Throw out bearing. Drop the tranny and change it out.

What the reason for the 90-140 oil? the manual says 75-90. Of course I don't take that as gospel just wondering if there is "insider" info there. Also any preference for dino vs synthetic in the tranny?

Your gears are loose. Thus the wine. The thicker oil will cushion it making it quiter.


BTW - Has to be Lucas Gear oil.

I figured I would replace the rear diff fluid at the same time, do you recommend using the same Lucas Oil 90-140 for that?

I have both of these issues as well.

I have run thicker gear oil in the diffs to aide in lunchbox locker noise, but I never thought of doing the same for the transmission. Thanks for the tip, Singtoe. I was told by a toyota mechanic with some experience that the most likely culprit for a noisy transmission was the front bearing.

As for the throwout bearing, I just live with it. The truck has a relatively new clutch, and I can't stomach the thought of pulling the tranny just for an annoying noise. :o

Changed the tranny and rear diff fluid today with Lucas oil, no change in the whine sound still there. Curious enough though the clicking in the throwout bearing went away. While I was under the truck I pushed the clutch fork back and forth with my hand while the engine was running and heard no noise. the interesting thing though is with as many time as I have been under my truck I never noticed the slave cylinder on the clutch is painted blue??? its the only piece of metal on the whole truck that is blue. When I changed my clutch 3 years ago I had the dealer do it and I wonder if they lost the original when the tranny was out and put in a rebuild.

My OEM clutch slave cylinder is also blue. I bought the truck new, and have never replaced it.

FWIW, I've had good luck with Redline oils. I would try their 75w140ns in your trans, if the Lucas gear oil doesn't achieve the desired results.

Since you have been under the 4runner. Can you take a closer look at where the sound is coming from?

When does it whine? At Idle, at highway speeds. Does whine change speed when you shift gears.

There is no whine when the truck is not moving. I drove down the road with my head out the window (I know), there is no whine when rolling down the road with the clutch in or with the truck in neutral. The whine is loudest when its in gear (any gear) and my foot off the gas and the truck is decelerating. I noticed a slight whine when pushing the gas pedal as the load shifted back to acceleration.

You can diagnose the noise by putting the transfer case in neutral and running through the gears. The sparkles in the oil should narrow it down also.

Hey, i have a 2000 4runner 5-speed with the same whine when decelerating except mine is almost more of a growl, one thing I noticed when trying to diagnose the problem is the noise goes away when I am in 4 wheel drive. Im not sure what that means just trying to add pieces to the puzzle.

So upon further diagnosis today I believe my pinion bearing is out in my rear end. I knew it was leaking but noticed a fair amount of up and down play on the drive line. This might be a good thing for you to check on yours. Im going to have a shop inspect it next week to confirm.

Went on a long haul yesterday with 4 people in the truck and they are telling me the noise is coming from the rear end not the tranny like I thought. Have to shift focus now and troubleshoot the diff!
If it is the diff is it better to buy a rebuilt one (and who from) or tear it apart and rebuild myself????

If you havent done a rear end before you would probably be in over your head I know I would be. Im probably going the ECGS route Drivetrain Specialists East Coast Gear Supply