Intermittent Whine

[Hoss]

OK, time to challenge all the noise guru's out there. Dealer replaced hydro boost Assy a few months ago due to the accumulator leaking fluid. Shortly after that, I noticed an intemittent whine. After it got louder and more frequent I took the truck back in. Dealer ordered and installed a new power steering pump... still had the noise. Just returned from dealer, installed another hydro boost. STILL HAVE THE NOISE! Any ideas?? Driving home this evening, I noticed that I hear it the most between 45-55 mph. Don't hear it on take-off, but hear it as soon as the speed levels out. When running down the road, the tone will vary if I slightly let up on the gas and feather into it again. When coming to a stop, will hear it but it goes away shortly (as in seconds)after a complete stop. Am usually pretty good at trouble shooting noises, but this one is driving me crazy!! Any suggestions?? It almost sounds and acts like a vacuum leak, but I can't seem to trace it. Any help would be most appreciated!

[Max_Nani]

I hear the whine during acceleration only...not very loud or irritating. I went to the dealer and was told it's normal for a diesel truck to whine.

[Russ Denman]

My truck has two whines. One is the Turbo. My son first noticed it but it took me awhile. It is very high pitched and changes pitch with as I accelerate.

The other whine is medium pitch and it the A/C compressor. It goes away when I turn off the A/C and comes back when I turn it off. I haven't had it to the dealer yet but will. It is more irritating than the turbo. The turbo is the same as a jet, the sound of freedom or power!
:D :D

[Barc]

Hoss - I know exactly what you mean!! I have had this mysterious whine since about 55,000 km - the truck now has close to 80,000 km and it has got louder. It is barely noticeable at idle and it fairly unpredictable when you are moving down the road - it is more noticeable on acceleration which leads me to believe it is either turbo or tranny. Mine seems to come from right below my feet or from the front of the engine compartment - one of my first thoughts was that one of the grommets/plugs had popped out somewhere between the engine compartment and the cab but I can't see it. My dealer can't find it and is a little apprehensive about ripping into the tranny or the turbo without knowing for sure what it is?!?! ANYONE have any suggestions????

P.S. I know it is not the turbo or the AC compressor - I hear the compressor cut in and out if I really listen for it and it doesn't bother me. The turbo whine is just the sound of music to my ears!! :D :D

[SoMnDMAX]

Look to see if any of the metal parts of the hoses leading to the Hydroboost unit are touching anything metallic. It's possible the harmonics of the hydraulic system are transfering thru the firewall, brake pedal, or steering column.

It's the only thing I can think of...

[Hoss]

Thanx for the quick responses... It is definitely not the AC or the turbo... I know those 2 sounds. I have previously checked all the lines going to the hydro boost and none were touching or even close. Hopefully I find and fix this soon, about to drive me crazy!

[Hoss]

Sound is becoming more prevalent now... Am going to do some more checking on it this weekend. Hopefully I can find the source of the noise. It is loud enough to hear over the radio driving with the windows down. Will let you know if I find the culprit.

[KompressorMan]

My truck whines at about 76-78 mph. I'm pretty sure it's the rear differential cause it's more noticable on long flat roads, especially after you ease up on the accelerator. I'll tell you this, after 50 (years) you won't be bothered near as much, your wife may still hear it but it'll just be "I don't hear a thing from you" Especially if you've had a diesel for, oh, say 15 years.
Herb smile.gif

[IndigoDually]

The whine in mine comes mainly from the passenger's seat when occupied. :D :D

Seriously I don't hear and whine but the oil smell and the front end rattle along with the column starting to rattle and the leaking rear axle seal might be dulling my senses.

I guess that leaks and rattles are letting me know that the truck is getting broken in. :rolleyes: