Humming sound between 40-55mph

[Slacker]

My '82 Deville seems to make a strange humming or whining sound from around 40mph to 55mph. Any speed below or above this I don't hear this. It sounds like it's coming from under the car by the transmission but I might be wrong.

Transmission fluid is nice and red and full. Car shifts fine.

The car's engine and trans has been swapped to an Olds 307 with a TH200 trans.

I'm a little nervous about this because I don't want to be driving an hear a loud "ping" and the car leaves me stranded again like it did when the HT4100 ate itself....

There also sometimes seems to be a lot of pulsating vibration noises at this speed too.

Thanks.

[mjs182004]

mine makes a humming noise also, but i think mine is normal. it sounds like a school bus at higher speeds. lol

[dirt_cheap_fleetwood]

Does the sound change if you move the wheel back and forth? Bearings are what causes humming noises like this. I'm guessing you either need wheel bearings (sound would change as you move the wheel and forces are exerted on front bearings) or the support bearing (can't remember if these cars have them) for the driveshaft.

[HUF]

Originally Posted by Slacker

My '82 Deville seems to make a strange humming or whining sound from around 40mph to 55mph. Any speed below or above this I don't hear this. It sounds like it's coming from under the car by the transmission but I might be wrong.

Transmission fluid is nice and red and full. Car shifts fine.

The car's engine and trans has been swapped to an Olds 307 with a TH200 trans.

I'm a little nervous about this because I don't want to be driving an hear a loud "ping" and the car leaves me stranded again like it did when the HT4100 ate itself....

There also sometimes seems to be a lot of pulsating vibration noises at this speed too.

Thanks.

Do some zigzags (S) and see if the noise becomes louder depending on the direction you turn to. If it is direction-dependable, it could be one of front wheel bearings.

[Slacker]

Sounds good. I'll be sure to take a look at that.

Currently I haven't really noticed any noise when turning but I haven't been looking for it either. I'll take the car out tonight and see what I find.

As for the support bearing, I don't think I have one of those. If I'm thinking of the right thing, my one piece drive shaft wouldn't have it. But now I'm curious also if it's maybe the angle of the drive shaft is in from after the engine/trans swap.

Thanks!

[dirt_cheap_fleetwood]

U joints rarely make a humming noise though. They will make a clunk or click type of noise as you get on and off the accelerator pedal (giving it gas vs. coasting).

[jayoldschool]

Get it up to around 50 on level ground so it is making the noise. Hold your speed steady. Shift from D to 3. Keep your speed the same. Does the noise change?

[Slacker]

Originally Posted by dirt_cheap_fleetwood

U joints rarely make a humming noise though. They will make a clunk or click type of noise as you get on and off the accelerator pedal (giving it gas vs. coasting).

Well I guess I'm good there then. No clicking or clunking coming from the drive shaft.

Originally Posted by jayoldschool

Get it up to around 50 on level ground so it is making the noise. Hold your speed steady. Shift from D to 3. Keep your speed the same. Does the noise change?

Sounds like an idea! One question though, my car only has a 3spd trans so I only have D, 2, and 1. With this set up, this will throw my car into 2nd when I shift the column lever, correct? I'm not sure if it would be safe to try this if this is the case though...

Tried the turning at low speeds when there was no humming and didn't make any noise. Tried it when it was humming and the sound remained the same.

The sound stayed the same if my foot was on the gas or not. So it's not dependent on engine RPMs just vehicle speed. I took my friend for a drive and he said it might be the tires making the noise. This might make sense. I just put on 3 new tires about a month ago with one tire I replaced last year. (Had maybe 300 miles on the tire. I didn't change because the car wasn't on the road because of the engine swap)

Maybe my 4th tire that I didn't replace got a "flat" spot from sitting?

Thanks for all the help guys!

[Stingroo]

Which tire was it that you left the same? Was it a front?

I'm at a loss really.

[Slacker]

Originally Posted by Stingroo

Which tire was it that you left the same? Was it a front?

I'm at a loss really.

Tire that was left unchanged was the rear driver's side.

I'm really not sure what to do seeing that the car drives fine otherwise. I just don't "trust" it in it's current state.

I really don't want to be bothered with mechanics either if possible. When I had a carb problem earlier, a bunch of mechanics were hesitant to work on it because of the engine swap. I even had one mechanic tell me "You did all this? Why don't you just fix it yourself and save the money." I did end up fixing it myself by putting in an edelbrock carb. (I got fed up with the old 70s quadrajet I had on there that I rebuilt 3 times in a couple months.)