Scary sounding whining noise

[justinburnett]

Sometimes when driving, my 1973 GMC k2500 develops a whining noise. This changes pitch according to RPM. Seems to only happen once it's warmed up a little bit and DOES continue if I stop and put it in park. It is intermittant and so far I haven't been able to get it to do it when I could take it to a shop to have them listen. I've gone so far as 200 miles with no problem, and then the next day have it happen just going to the store. It drives normal, no weird vibrations or loss of power. Checked all fluids and they're good. Honestly sounds almost like a power steering pump when it's low and you lock it to one side. The only thing that I've noticed is different as far as operation goes is one day it did seem to hesitate when I went to take off from a stop sign, but I'm not 100% certain if it really did have a delay or not. Was not making any strange noises at the time. I have checked fluids in engine, trans, all diff cases, transfer case, and PS pump.

All I have done lately (last 4 months) is replace the starter and flexplate, and change the fluids in the transfer case and rear diff.

Please throw some ideas my way that I can check and see if that's what it is. I'm worried about it causing worse problems if I drive it, and I need to from time to time.

[silvereagle07]

First you need to determine what area the noise is coming from (engine, trans, transfer case or rear). If it's coming from the engine are take the belts off to see if it goes away. You can also use an automotive stethescope to determine the noise. They are really cheap and help alot to determine faulty bearings or internal noises. Good luck.

[jablack]

I built an engine once and had that problem. Turned out to be the front main seal behind the balancer. I swapped that out and the noise went away.

[old Rusty C10]

i second the idea of the stethescope... ive tracked down many a wayward noise with those things

[justinburnett]

It'll be a little bit before I can get ahold of a stethescope. Probably early afternoon. Then there's the problem of getting it to make the noise on command but as soon as I have a better idea as for location, I'll let you know and go from there. Thank you.

Is there any way to check the front seal without pulling the balancer? It's not really leaking anything much. Coupla drips here and there but pretty much normal old vehicle stuff.

[notrailerqueens]

if you cant get ahold of a stethscope you can always just use a long extention, screwdriver, something of that nature you can get the same results with out having to go get a stethscope. old hot rodder tip i picked up a long time ago. *shrug* hope it helps

[Buick455]

Could be a trans. pump whine. You changed the flexplate so you removed the trans. Did you check the fluid ruining and level? Are your trans. coolant lines kinked? Did you change the trans fluid and filter? Did you use the correct fluid?

[justinburnett]

I actually pulled the engine instead of the transmission. I had a hoist, but no trans jack, plus I don't know anything whatsoever about transmissions and I didn't want to mess with it.

Yes, I suppose it's possible I messed up the lines somehow, I'll look in the morning. I did disconnect the trans lines from the cooler since I had to take the radiator out. Put them back though and shouldn't be a problem, but I'll check fluid again and also check the connections on the cooler.

I'll look in the morning when it's light. I got the stethescope but it wouldn't make the noise for me to listen except for a few minutes while driving but it was stopped by the time I got pulled into a parking lot.

[Buick455]

Did you plug the trans lines with something, small rag and forget to take the plug out? Note: If you were in VA and did not plug the lines you would have about a dozen stink bugs residing in the lines, LOL.

[justinburnett]

Nope, didn't plug them when I took them out. Hope nothing got in there.

[justinburnett]

Still haven't gotten it to do it when I was able to check. Started for a second yesterday while I was driving but it stopped again as soon as I found a place to stop. This is really frustrating.

[pig rig]

when it makes the noise is it a deep growling whine and does it sound like its coming from the engine or from your feet? if it sounds like its coming from the front get it warmed up and with the truck stopped turn the steering wheel lock to lock then drive it if it starts to whine you might have air in your power steering system

[justinburnett]

not really a growl, more like a mid to higher pitched whine. Sounds like from up front. I'll check the PS situation cause I did run it dry on accident when I pulled the lines before.

[justinburnett]

Still nothing. This is really irritating, I ask for some help and she goes quiet on me.

No problems the last few days other than having to try to start it a couple times this morning when it was 14 degrees.