Vehicle Whine

[Romer]

Mine starts as a whine building up in volume (and speed) and goes along with the speed of the vehicle. It changes tone and does the opposite as you deccelerate. It definitly is somethiong rotational.

Don't think mine is the exahaust, because I can shift from D to N and going down hill maintain the same speed and the sound is unchanged. The engine RPM drops down to idle which would impact the Exhaust outputy.

 

[atijerino]

My '94 has the same whinne as you described, it seems to reach the perfect harmonics at around 72Mph and it becomes less evident.
I took the truck to the local dealer for a "sure" diagnostics, they came back with a diagnostics that the driver's side inner-axle was worned out and that the front axle spindle bushing needed repalcement. The estimate was $600.00.
I took the front axle apart and did not see any noticeable wear on the inner axle and the bushing did not seem worm, the outer axle shaft does not ride on this bushing, it rather floats on the bushings
I repacked the birfs and installed new wheel bearing, after this the whinne still perssits, I am leaning more towards the rear u-joints and slip spline yoke, second choise output diff pinion bearings.
I guess I have continue eliminating possible causes until I hit the root cause.

Thanks,

Thanks,

 

[Romer]

Robbie,
Can you help me with the two statements. If I determine it to be the rear output by the driveshaft test, i want to know what to do. If its all one peice, then might as well just pull the T Case

The rear output can be done with out removeing the t-case.

YOu have to pull the whole housing as the outputs are one piece and need to be disasmebled from the inside out.

 

[IdahoDoug]

Ken,

Sorry to kinda start you at ground zero here, but did this whine exist before you guys did the front axle repack and all the work - in other words did you buy it this way?

Other than the usual faint whining and whirring of a bunch o' gears on the 80s I've had/driven (lots), the only true whine that was loud enough to be a concern was a front diff. The owner had persistently let the front diff get low due to not keeping the front axle seals in shape and the high pinion design caused it to suffer first as it's high in the diff. Frankly, it was tough to discern where the noise was and I could have easily been convinced it was the center diff because of the way sound travels through metal. I used the patented method of duct taping a length of garden hose to each major component as I took it for a quick spin and in 15 minutes there was no question about the front diff being the source.

DougM

 

[Romer]

The sound is new in the last week. I took it to a shop that put it on a rack and isolated it to the Tcase "area". The noise is gets loud enough that I am concerned about wear and damage. I do not want to break down in Moab. Per Robbie's advice, the sound changed (not a lot) when going to a thicker lube.

I changed the front diff fluid when I bought and then again after the re-pack

 

[atijerino]

Doug,

Can you tell us more about this "duct tape" method?


Thanks,

 

[IdahoDoug]

Ah man (rolling eyes) you guys are gonna think I'm crazy. I've used two methods to find sounds quickly that are as ancient as Cdan (well, almost). One is using a wooden dowel pressed against a mechanical device to listen to it very clearly. You put the other end against your ear (actually pressing against it) and it's amazing what you can hear. Just be extremely cautious about this. I don't think I need to elaborate on what happens if the other end gets hit by the fan or caught in a moving belt since it's a half inch from your brain. I used this method as recently as 3 weeks ago on the new 97 when I was bummed it appeared the A/C compressor bearings were going. 5 minutes with a dowel and I could clearly hear it was the belt tensioner under the A/C compressor and it's sitting on my bench awaiting install ($15 vs pulling the entire A/C compressor).

Another method is using a length of garden hose the same way. You may recall that up until WWII, officers on the bridge could speak to the engine room hundreds of feet away with speaking tubes, and this is the same principle. Hold one end against a component and listen.

What I did was cut a garden hose long enough to go out the window (run it out the farthest away window and tape the window gap so you're not trying to listen over wind noise) and taped it so the cut end is directly against the front diff. Get a good seal so you're also not getting wind noise from under the truck. Don't be stingy with the duct tape to prevent it from coming loose underway - tape it along the body, etc.

Driving down the road, you'll be able to clearly hear the difference in gear noise when the differential gears are on their drive faces (power on) and when they switch to the angled coast side. Believe me, there's no subtlety here - it's as plain as day when you're listening and it will bring a smile of disbelief to your face the first time you use either a dowel or hose. Switch to another suspect component and go for a drive. I brought the tape with me and old clothes so I could just pull off and switch the hose without going all the way home. Boom - case closed.

Works like a charm, just be sure to wear your Junk mask so the neighbors don't call you in....

DougM

 

[Romer]

I was going to bring it into Christo, but he asked me to try something first. He is a good guy, he could have just taken my money.

He told me on his 100 series the drive shaft on the 100 series didn't have a slot of "spring" in it, and it made a similar noise. He told me to take the drive shaft off at the diff and remove the spline. Mark it before I do because it has to back in the exact same place to remain blanced.

Clean it out, there was some gunk that would have been beteen the shaft and the outer casing of the spline. I also cleaned out the grease from the inside. I re-nstalled it and greased it.

It's snowing here and the streets are a little wet, so I don't know if that deadened the sound, or kept the tcase cool so it didn't make it. BUT, the sound went from a volume 8 to a volume 2. That may even be normal, I can't remember. I'll drive it a few days and see and post back if it's gone.

Just thought I would post it up in case others want to try this. Christo said it solved his problem.

Ken

 

[IdahoDoug]

Which drive shaft are you speaking of?

DougM

 

[sleeoffroad]

He told me on his 100 series the drive shaft on the 100 series didn't have a slot of "spring" in it, and it made a similar noise. He told me to take the drive shaft off at the diff and remove the spline.

It must be my South African accent. OK, what I said, I had a similar noise on my 02 Land Cruiser. In an effort to track it down, I removed each end of the rear drive shaft to check the smoothness of the joint. Also checked if the slip joint would compress properly.

Well it did not. Removed the zirk fitting for the splines and compressed it by hand all the way to press out excess grease.

Then I marked both ends, separated the slip and cleaned everything. Light coating of grease on it and re-assembled.

There was a whole tread on this a while back where IdahoDoug posted on how to do this and how to grease it.

This took care of the noise on mine, in conjuction with greasing each ujoint. Always start at the shafts first before you yank a transfercase.

Finding noises is pretty much a process of elimination. However I do have a set of ChassisEars coming so we can pinpoint noises better.

I believe if the shafts do not want to compress then they put forge on the drivehaft and transfercase inputs and this might also cause noises and eventually bearing failures.

 

[Rookie2]

Woody,

I think I've got the same howl that you've got. Mine is more prominent in the 45 to 55 range, and loudest under very light trottle. Goes away as so as I let off the gas. I've removed and degrease my rear driveshaft. Need to do the front and see if that helps.

Please post up if you figure anything out.


Rookie2

 

[Romer]

It must be my South African accent. .

Naw, it was an expert mechanic talking to a 1-2 bannana mechanic. I had never taken off a drive shaft before so I "couldn't picture" what you where talking about when you told me. Now I can.

Would the thicker weight grease I switched to 90-140W make it louder and still create some noise if the process you told me fixed the problem? I haven't had a chance to drive it much, but it is much quieter.

 

[Rookie2]

How are you guys cleaning the grease out, that is packed in at the end of the sleeve that covers the splines on the end of the drive shaft?

Thanks,
Rookie2

 

[IdahoDoug]

I used gasoline and a wood shish ke bob skewer (the throwaway kind...) to run along each spline. Then a blob of paper towel on the non sharp end to get the stuff out of the end. Then I used brake cleaner to get any remaining residue. Took several cycles of pouring gasoline down in the splines, mucking around with the paper towel, pouring out cruddy gasoline and repeating until it came out clear. Be sure to let it air dry after the brake cleaner for a bit so you're not putting grease in while there's a solvent left. Think I used a tooth brush on the felt/velcro-like seal you'll find.

When you reassemble, simply grease the splines manually. If you can't compress the shaft on, remove the zirc and it's easy.

DougM

 

[2cruisers]

Rookie2

My 96 has the exact problem as yours, starts at 50 under very light throttle disappears under acceleration or coast. Let me know if you figure this out, I'll do the same

 

[Romer]

Took it to Slee's. Both Christo and Robbie drove it and said it was likely the front bearing in the Tcase. Going to leave it there and have them fix it.

 

[IdahoDoug]

Can't get any better analysis than those guys, and they're certainly going to be both conscientious about fixing it and efficient with their(your) shop time. Sounds like your center diff (I know you like calling it a Tcase - heh) was low on oil at some point.

DougM

 

[Romer]

Your right, center diff. Still thinking like it's a 40.

Christo thought the same thing

 

[Romer]

Robbie (Slee Off Road) put on those fancy new listening ears and took it for a drive. Said there were apparently 3 distinct sounds and that more than just the output bearings were bad. The fact that I had crap come out when I switched to the thicker lube and also had a burning smell that I couldn't figure out means my Tcase is shot

Robbie presented the options as follows:
1) Rebuild (Very labor intensive) $$$
2) Install new $$$$$
3) Install a used one that Christo knows the history of $$

I decided to go with the used one. Robby drained it and there wasn't any crap in it.

They think the PO (of my tcase) let it get low on fluid for some time. Doug said the same thing.

It's a bummer, but I am getting quality work at a reasonable price from people who know their stuff. I should be thankful that I know Christo and Robbie. Otherwise, I would be

I thought I would post the answer to complete the story. I used a lot of searches in trying to figure this out and I always hate it when you don't know about the final solution.

 

[IdahoDoug]

Ken,

You're exactly right - it's nice to hear the end of the story. Glad you're in good hands.

DougM