More Whining...

[Tachycardic]

Did some searches, but didn't find what I was looking for so...

I have a stock '94 (278k miles) that whines a little starting at 40mph--not a big deal. However, at 60mph and up, it gets pretty loud. The whine only occurs with throttle. The whine stops immediately off-throttle, and if the speeds dip below 60mph, it's pretty quiet even with throttle. The vehicle itself runs smooth, has new oem and Gates belts, transmission fluid is new, replaced the front diff fluid recently, and installed a knuckle rebuild kit with new Koyo bearings. The throttle cable is original, and looks pretty ratty; I'll be replacing that next, but can this noise be caused by an old throttle cable? Older threads have pointed to the differentials or bearings...just looking for some new suggestions. Thanks.

 

[jfz80]

From that description i woulda guessed pinion bearing first. Mine does it to so following along.

Any skids? Or armor that could be contacting driveline picking up harmonics?

 

[MrMikeyG]

is there a very specific rpm range involved? Mine has a resonance whine thing that happens plus minus 50 of 1900 RPM. Letting off throttle mine goes away as well.
Curious what happens here.

 

[Tachycardic]

No skids--using factory running boards. No body armor--yet.

I've noticed that at 60mph, the engine is turning just shy of 2200 rpms. At 65mph, it's turning about 2300 rpms. However, when going from 30-50mph, I'm revving up to 2400 rpms and I do not hear the whine. It's related to speed more than rpms.

 

[Rusty Marlin]

Just had a guy here going through something similar and it was the rear pinion bearing.
Dude's out of Mass. and drives a jacked up OD Green Rig.

RFB is his handle here on MUD.

 

[Tachycardic]

Just had a guy here going through something similar and it was the rear pinion bearing.
Dude's out of Mass. and drives a jacked up OD Green Rig.

RFB is his handle here on MUD.

Ok thanks...will have to look into it... BTW, is it Richie from Jailbreak Overlander? He's got a sweet ride.

 

[Rusty Marlin]

Yup, that's the guy. His rig is sweet. A lot of time and effort went into that beast.
At any rate, he just went through a similar kind of whining with throttle, let off and it would die kind of noise.

 

[MrMikeyG]

was it the front passenger wheel noise post? I may need to look through again.

 

[Rusty Marlin]

Strange noise Can’t pinpoint

So I’m in Colorado ouray to be exact. And I’ve had this noise since Boston that I can hear when next to a highway divider or small street. Sounds like something is stuck in brake protectors like a scraping BUT it stops if I touch the gas even in the slightest . I pulled apart the brakes etc...

forum.ih8mud.com

 

[Tachycardic]

My truck's condition is definitely different from RFB's. He complained of a scraping sound that went away with throttle. My whine goes away off-throttle, and only occurs at 60mph and up. I have a little bit of time before my next Death Valley trip. Going to do the easy less time-consuming stuff first like regreasing the drive shafts and yokes and checking/changing the rear diff oil (front was just done last week).

 

[Tachycardic]

was it the front passenger wheel noise post? I may need to look through again.

Interestingly, when my wife drives the truck and I'm sitting in the passenger front seat, the whine is less pronounced. It is still there, but not as loud. Wonder if there's some sort of harmonics-thing going on.

 

[BILT4ME]

Interestingly, when my wife drives the truck and I'm sitting in the passenger front seat, the whine is less pronounced. It is still there, but not as loud. Wonder if there's some sort of harmonics-thing going on.

If there's more whining when the wife's in the passenger seat, maybe not have her ride along? That usually fixes the whining in my truck.

 

[Tachycardic]

If there's more whining when the wife's in the passenger seat, maybe not have her ride along? That usually fixes the whining in my truck.

Haha. She actually likes the truck, which is even more impressive considering how "eco" she is.

 

[Tachycardic]

Just a small update...I was replacing the air filter and was inspecting the air intake tube and noticed that it had worked its way out. Clearly, the tube is modified and has a 3 inch diameter metal insert about 5 inches long. This metal insert is directly over, but not touching the engine head cover--there's about 1/2 inch of space between the two. Anyway, with everything in place and tightened up, I went out for a drive. The whine is still there at 60mph+.

I will regrease the driveshafts with Valvoline Palladium (thanks for the suggestion Kernal) within the next 2 days and let you know if it helps.

 

[amgraham]

I'd be pretty surprised if it wasn't differential whine. I'm assuming since you were poking around the engine compartment it sounds like it's coming from the front. Do you have a CDL switch? If so, pull the front driveshaft, push the button, and go for a drive (this essentially makes the truck rear wheel drive). If the noise is gone then you know it's in the front diff.

I had the same problem and drove it for the better part of a year this way, only putting the driveshaft in to go wheeling. I had the diff out 3 times and I'm normally pretty good with them and couldn't get it to go away. Ended up taking it to an expert and he said the ring and pinion was worn to the point it would always whine.

Options (in order of fixing it properly):

1. Buy a new ring and pinion and bearings, install/have installed. Great time to add a locker.
2. Find a used 3rd member that's in good shape and swap it in. This is what I did.
3. Convert to part time. Only have whine when you're in 4wd.

Mine was so bad I couldn't have a conversation in the truck at highway speeds, which is why I just drove it in 2wd for so long. Since I replaced the diff everything has been good. It's a major pain to swap that front diff but with a little practice I got it down to about an hour haha.

 

[Tachycardic]

Thanks for the suggestions amgraham.

A small update...I greased the yokes (took about 10-12 pumps each from a Lincoln 1143) and slips (36-40 pumps each) with Valvoline Palladium (thanks for the suggestion kernal). The whine has diminished somewhat, but is still there. I'll consider replacing the pinion bearings, but the whine is now tolerable and will wait. I do have a CDL switch and will consider pulling the front driveshaft after the holidays to see if it is the front diff. Thanks again.

 

[510FJ80]

I noticed the same noise you are experiencing today. Looking forward to learning more. subbed.

 

[EvanD]

40 pumps? Maybe its a difference in grease gun (mine is whatever from harbor freight or AutoZone, can't remember) but that seems really high from my limited experience.

 

[Tachycardic]

I don't know what to tell you evan. I counted the pumps until the slip joint started to move and thats what I got. Using a Lincoln 1143.

 

[BILT4ME]

I have two types of grease guns. One is a long handle that moves a significant amount of grease per pump. The other is a handheld squeeze handle pistol-grip type and it only moves a fraction of the amount of grease per pump as the other. I will put in 4 pumps of the long handle to about 20 of the pistol grip. Just a guess, no scientific checking there.

So, "number of pumps" is subjective. When on the farm, we had about 20 grease guns. Every one had a different amount of pump per pump.