I have a 2001 Toyota 4Runner SR5 with AT and V6 with 70k miles on it with pretty much everything loaded. The car has been trouble free since I got it 3 months ago. However,the past month, the engine has been making a high pitched "squeaking" noise whenever im at a constant speed. If I accelerate or brake, the noise goes away. I also noticed today that it stays constant no matter what when im in 4WD mode, but when Im in 2WD it behaviors like I describe earlier. I had the Toyota dealership do a complete lube service and they found two of the belts were "dry" and relubricated them however the problem persistated. The noise doesn't happen when im in idle or at a stop either. The noise seems to eminate from the right side of the engine.

Also, do 4Runners have a noisey brake cylinder system? Almost everytime I brake I hear this slight "Pssssssssssssssssssss Tick!" sound from the engine. The car brakes just fine and the Toyota dealership found nothing out of the ordinary but i've never heard a car break that noisey before. This a 4Runner trait?

Do you have any idea what could be causing these two noises, especially the gawd awful squeaking noise from the engine. It never made that noise until just one day...wallah, outa no where and I can't stand it!!!!

I have (mostly) the same issue with our 1999 4Runner. Squeak in front ride side only when driving. In the early stages it only appeared at a constant 30-45 MPH. Now it's constant unless speeding-up or braking.

Today I removed the right front tire along with the brake and rotor. While turning the drum could hear nothing. Went ahead and lubed what I could. Reassembled it and sure enough ... took it for a test drive and heard the constant (rotation) squeaking at nearly any speed. Sounds like the front right drive axle , but couldn't access due to clamps on the rubber boots.

My wife is about to put this annoyance out of it's misery and just trade the POS in for something new.

No one else has any ideas? Man....just my luck... :crying:

Does the engine squeak when you are stopped, but the engine is reving at say 1500-2000 rpm (cruising rpm)? or does it only squeak under load (driving)?

Since it only squeaks constantly when you're in 4WD, I would attribute it to a part from the transfer case forward, and not the engine. Since it is the right side, it is most likely a wheel bearing, or a CV joint. Lube or replace them. It is also possibly the bearing in the front differential, but that probably wouldn't sound like it's coming from the right side.

The noise you're hearing when braking is not normal. Get it repaired.