Question Transmission howl at low rpm

[jbtech2]

My 2000 Tundra trany has started howling at stop lights, idling in any drive gear, but not so much in park or neutral; the sound goes away when rpms increase, even slightly. I've been doing internet searches and find two things: 1) I should suspect the torque converter and 2) first thing to do is clean the trany filter.

Questions: do these sound like plausible conclusions? Any advice on cleaning the trany filter? Will a good trany flush work? How's about opening the drain plug, starting the engine, and engaging drive for a few seconds to drive out all the fluid? The fluid is bright red(I changed it about 5k ago), and not a hint of burning smell.

I sure will appreciate all responses/assistance!-jer

[NRA4Life]

Try posting your question in the 1Gen-Tundra forum.

[ICON]

Are you sure it's coming from the tranny? I've had numerous idler pulley's, tensioner pulley's, and other engine accessories w/bearing howl(not in the Tundra) but never a noise from the tranny. First make sure the fluid level's good. I am highly doubting cleaning the filter will make a difference but i guess dropping the pan would tell if the tranny's eating itself. I wouldn't run the engine to drain the fluid.

[jbtech2]

Thanks all for the input. That bearing howl is what I will pursue for now. I did change the timing belt back in June, but didn't change anything but the belt. That may turn out to have been a mistake. I guess a stethescope on the timing cover and on all the rotating other assemblies should pin it down. I'll let you all know soon what the solution was.

[jbtech2]

Okay, the tale of the stethescope reveals the howl is coming from the alternator. It sits low enough that I guess the lower engine cover routed the noise back to the area of the trany. If one walks around the truck, you'd swear it was coming from the trany. I found this by the barest hint of a howl thru the steth (actually, a 2 foot length of 1/2 inch pvc pipe), and then by turning the headlights on and off. When the lights come on, the howl goes way up, and goes down immediately when the lights are turned off. Way cheaper than a new trany!! Thanks for all the good clues, Icon.

[ICON]

Just an FYI, you can replace just the bearings since these alternators are very expensive. Not sure if Chinaloy is still around but i printed a post from him a while back where he had the same problem and got the bearings from Toyota. The front bearing part #90099-10192 & rear #90099-10194. He said it went well with only a few specialty items needed such as a small puller to seperate the case halves. The rear bearing was pressed in but not exactly sure how he got it out. And the front is held in by 3 screws and a retainer.

I don't recommend remans from parts stores when it comes to alternators or starters, i've had so many be junk right out of the box that it'd rather replace bearings in an oem one that buy a reman.

Oem alternator: $480
Oem bearings: $20