Weird Humming/grinding at low speeds, feels sluggish. Help?

[Chandler_Ross]

So I've had my 3rd gen for a while now. I just got my 4th gen a few weeks ago. 2003 Limited 4x4 at 103k. So far I love it. I'm gonna go broke with the timing belt and tires that need to be done. Now to top it off, I've got a bigger problem which seems like it will be costly. I'm getting a humming noise at 20-30 miles an hour. It's consistent with the wheel speed. What gear I'm in has no effect on it. No change in locking the center diff or in 4Lo. It feels like it's hung on something. After some research, I'm leaning towards wheel bearings, U-joints, or something in the front diff or transmission. I've seen a few posts describing this issue. Some ended in wheel bearing replacement. A few ended in transmission replacement over a problem even Toyota can't fix. It doesn't do it all the time. So far it has only done it twice. Both times in the same place on the same road. Both times I've checked for anything that could be rubbing or making contact, and can't find anything. It's kind of scary to drive the thing when it's happening. It feels really sluggish until the noise goes away. Then it's back to normal. Any help? I'll take it in to my mechanic tomorrow. But I would like to know what you guys think before I start throwing money at it.

 

[mallard]

V6 or v8? If 6 and the 1gr-fe, you will be thrilled to know you will not need a timing belt. If you have a v6, you will immediately feel like you are making money (for a few minutes until you mentally spend it on a lift)

 

[Chandler_Ross]

Meant to put that it's a V8. Haha. I absolutely love the iForce. I don't love the fact that it's the only Toyota motor ever made that is timing belt driven and also an interference motor. Otherwise I'd probably never change the timing belt. My 3rd gen is about to hit 170k on the original.

 

[Derek G]

So I've had my 3rd gen for a while now. I just got my 4th gen a few weeks ago. 2003 Limited 4x4 at 103k. So far I love it. I'm gonna go broke with the timing belt and tires that need to be done. Now to top it off, I've got a bigger problem which seems like it will be costly. I'm getting a humming noise at 20-30 miles an hour. It's consistent with the wheel speed. What gear I'm in has no effect on it. No change in locking the center diff or in 4Lo. It feels like it's hung on something. After some research, I'm leaning towards wheel bearings, U-joints, or something in the front diff or transmission. I've seen a few posts describing this issue. Some ended in wheel bearing replacement. A few ended in transmission replacement over a problem even Toyota can't fix. It doesn't do it all the time. So far it has only done it twice. Both times in the same place on the same road. Both times I've checked for anything that could be rubbing or making contact, and can't find anything. It's kind of scary to drive the thing when it's happening. It feels really sluggish until the noise goes away. Then it's back to normal. Any help? I'll take it in to my mechanic tomorrow. But I would like to know what you guys think before I start throwing money at it.

Have you tried checking the wheel bearings? Jack up one wheel off of the ground, then grab the top and bottom of the tire and rock it towards and away from the truck (perpendicular to the way the tires steer) then lower the tire and try the other side. If you have any play at all you have bad wheel bearings. If that is the case get them replaced IMMEDIATLY. Bad wheel bearings will cause all of your front brake components to go bad and that can be much more expensive than replacing the bearings themselves.

 

[Chandler_Ross]

Have you tried checking the wheel bearings? Jack up one wheel off of the ground, then grab the top and bottom of the tire and rock it towards and away from the truck (perpendicular to the way the tires steer) then lower the tire and try the other side. If you have any play at all you have bad wheel bearings. If that is the case get them replaced IMMEDIATLY. Bad wheel bearings will cause all of your front brake components to go bad and that can be much more expensive than replacing the bearings themselves.

It's in the shop now. Hoping it is wheel bearings and not something like a bad front diff or transmission. But I can't get it to make the noise again! I had it happen the other night, and about a week prior. I have no idea what triggers it. It's just randomly happens. My mechanic hasn't had the problem yet and has been driving it for the past 2 days. I wish it was easier to diagnose.

 

[Chandler_Ross]

Is it normal for wheel bearings to fail this early? The truck came from Pittsburg and has it's fair share of rusty bolts. Nothing too bad. I wouldn't think parts like bearings/joints/etc should be failing this early.

 

[zonianbrat]

I've had both bearings replaced up front (one of them twice in 6 months due to the shop pressing it and bending the flange) in my experience when they go you hear them but it doesn't feel sluggish. Does it have a day star leveling kit? Mine does and it is causing a needle type bearing to rub in the front diff. Really common problem when you lift a tacoma. I can feel the rubbing at 35 to 45 m ph. If I put it in 4 it goes away because everything starts rolling and tightening up in the front diff. Hope any of this info helps you. Good luck and let us know what it turns out to be.