O.K. I've done all sorts of searching on this and come up with two forum threads that describe my 4Runner's symptoms exactly: one guy was told that his transmission pump was going bad, so he traded his 4Runner in to get a different car; the other guy was told that his transmission needed to be replaced, so he replaced it (at high cost).

I'm hoping somebody else has had this happen and can tell me the resolution without letting a mechanic have his way with me!

The model: 2002 4Runner SR5 4WD, automatic transmission

Miles: 218,000

The symptoms: I'm hearing a whine when I put my transmission in Drive or Reverse. The whine sounds like gears -- kinda like when you hear someone backing up really fast. If my car is parked, there is no noise until I shift into Drive or Reverse. There is no noise in Park or Neutral. When I start driving, the whine increases in frequency with engine RPM, but the whine stops if I shift into Neutral or let my foot off the accelerator pedal. I notice it in first and second gears. It's too quiet of a noise to hear if I'm going fast enough to be in higher gears.

I've done some close listening, and the whine is definitely not coming from the engine compartment. I hear it most clearly under the car (where the transmission is!).

The whine seems to be more noticeable when the car has not been driven for several hours.

I've done a complete transmission fluid flush twice over the life of the vehicle, and the fluid has always looked and smelled good. I use Mobil 1 synthetic ATF. The current ATF level has been checked, and it's good.

Before I shell out a whole mess of dough to replace an entire transmission (since that's what the mechanics will likely want to do), has anyone experienced this before and resolved it by replacing a transmission pump? Is there even a transmission pump? My Hayne's manual doesn't mention a transmission pump anywhere.

Thanks for the help!!!

 

Did anyone answer you because I have the same issue?

 

No. I posted this on a few forums, but I only got speculations as to what the problem was.

I found that general mechanics wouldn't even look at my car without charging a diagnostic fee of around $100. It was the same with the dealerships.

However, transmission repair shops were VERY helpful. I went to three different places, and they all had a mechanic drive around with me to help diagnose the problem without taking anything apart. Since they were generally in agreement, I ended up having one of them do the work.

So the problem was in the torque converter. I am a mechanical engineer and do a fair amount of my own car repairs, but I don't know much about automatic transmissions, so I can't provide more specific details about what exactly was wrong with the torque converter. I could see that the parts were worn, though.

Anyway, while the transmission was apart, they showed me some other things that could be repaired/replaced. That's what mechanics do best, right? At the time, I only wanted to get another 20,000 miles out of my car, but they were confident that I could get another 100,000 miles with the suggested work. Since this place had a good reputation, I agreed to the additional work.

In the end, most places were quoting me about $3200 to replace the transmission with a rebuilt unit. However, the transmission repair cost $1600, and it had a decent guarantee.

I've since driven 12,000 miles, and everything is still going strong.

Summary: Take your vehicle to a few local transmission places and be prepared to spend $1500 - $2000 for a repair that will last a while.