The only mention of putting the transmission into neutral was in the context of a post on another forum and in your own post.

No other posts in this thread has suggested that the action you object to actually be taken. And certainly not with the added complication of towing.

A drivetrain can also be put into "driven" versus "driving" conditions with respect to load by being on the gas or coasting.

In the case of the ring and pinion, this changes the surfaces that are handling pressure. If there is a defect, the noise characteristics will likely change.

 

Found this to be easier to copy and paste than me to type it all out from memory:

Howl while decelerating. (Used to be quiet) Loose pinion bearing preload.

Howl while accelerating at all speeds accompanied by a whir or rumble. (Used to be quiet) Worn rear pinion bearing and possibly worn gear set.

Howl while accelerating at all speeds not accompanied by a whir or rumble. (Used to be quiet) Worn gear set due to lubrication failure or overloading.

Howl while accelerating over a small speed range. (Used to be quiet) Worn gear set due to lubrication failure or overloading.

Gear set howls as soon as installed. May be due to design or improper installation.

Low pitch rumble at all speeds over about 20 mph. Noise can change while negotiating turns in semi-float axle design. Worn carrier bearings

Whirring noise when decelerating at all speeds above about 10 mph, when accelerating at all speeds above about 10 mph, or while both accel and decel. Possibly accompanied by a rumble Worn pinion bearings. (Usually cause more of a whirring than a rumble due to the rotational speed)

Banging and clunking while negotiating a turn, while backing up, and/or while taking a freeway off-ramp. Sounds like someone is banging on the rearend with a 40 lb. Sledge hammer. Problem gets worse as differential heats up. Positraction chatter due to improper lubrication, worn clutches, worn spider gears, or improper assembly.

Banging, crunching, or popping while negotiating turns. Does not change when differential heats up. Broken or badly worn spider gears.

Rumble or clicking noise that gets worse when vehicle is turned hard right or hard left. Bad wheel bearings.

Squeaking or grinding at speed of driveline. Worn or damaged universal joints.

Clunk when taking off and/or getting on and off of the throttle. Worn u-joints, worn spider gears, worn axle splines, excessive backlash, loose yoke splines, or worn slip yoke splines.

Clunk just after taking off from a stop. Worn slip yoke splines.

Vibration that is steady and increases with vehicle speed. Worn u-joint or driveshaft is out of balance.

Vibration that is cyclic (increases and decreases in intensity and is not steady) and is more pronounced over a specific speed range. Vibration gets worse when accelerating. Pinion angle is to high and needs to be pointed down until parallel with front driveshaft yoke.

Vibration that is cyclic (increases and decreases in intensity and is not steady) and is more pronounced over a specific speed range. Vibration gets worse when decelerating. Pinion angle is to low and needs to be pointed up until parallel with front driveshaft yoke.

Banging or heavy clicking noise about every 8 feet while both accelerating and decelerating. Broken or damaged ring gear tooth (or teeth).

Banging or heavy clicking noise about every 2 or 3 feet while both accelerating and decelerating. Broken or damaged pinion gear tooth (or teeth).

Banging or heavy clicking noise about every 8 feet while either accelerating or decelerating but not both. High spot or heavy chip on ring gear tooth.

Banging or heavy clicking noise about every 2 or 3 feet while either accelerating or decelerating but not both. High spot or heavy chip on pinion gear tooth.

Clicking noise while decelerating from about 20 mph to a stop. Worn carrier case side gear bores.

 

@beav,

That's a pretty comprehensive list. It should cover just about every defect that could possibly be encountered.

It's the kind of knowledge that becomes harder and harder to find in the land of 200 word throwaway blog posts replacing real printed words on real paper.

 

Thanks Beav, that's very handy. Printing a copy now for future reference!

 

"Howl while accelerating over a small speed range. (Used to be quiet) Worn gear set due to lubrication failure or overloading."

"Vibration that is cyclic (increases and decreases in intensity and is not steady) and is more pronounced over a specific speed range. Vibration gets worse when accelerating. Pinion angle is to high and needs to be pointed down until parallel with front driveshaft yoke."

I've got one or some combination of these two. Still looks like it's the diff either way. Possibily a driveshaft in need of rebalancing as well. Will probably do that first and see if it cures anything.

 

Doubtful the pinion angle has changed without severe accident damage. However, the front of the shaft may have dropped due to a failed transmission mount. The u-joints don't have to be equal in height above the imaginary plane but they do need to be parallel, within 1 degree. "Vibration gets worse while accelerating" is also very indicative of one or more bad u-joints. Usually accompanied by 'squeak squeak squeak....' and/or 'ting!' when first placed into gear.

 

... ummm skidmark, weren't you the one with the transmission mount replaced?

 

No squeaks or tings, u-joints are tight, no accidents that I know of, and we replaced the transmission mount a couple of weeks ago. We did give the pinion nut about a 1/8 turn a month ago to tighten it up a bit, as well as a couple of ounces of clutch cleaner into the diff housing.

 

Yes, helped eliminate a buzz in the drivetrain, but was soon replaced by the howl.

 

You might hve a u joint getting tired,hard to say without hearing the noise in person, do you see any vibration in the rear view mirror when the noise is present? The diffs are pretty robust on these cars would be surprised if that was the cause of the problem, wheel bearings tend to get noisier with load ie. left or right turns. Your prop shafts have u joints too, they can also present noise when cornering. Grease all the ujoints and see if it gets alittle quieter, not a fix,but might help you pin point the problem, uj's are an easy fix if you need them.

 

So maybe it has something to do with:

How was the need for additional preload determined?

Why and what clutch cleaner? Do you have a clutch pack LSD?

 

Skid,

I'm sure this has occurred to you, but I'd say these two events are linked. Have you talked to the guys who were helping you with your driveshaft a while back?

 

I heard the howl for the first time before we tightened the nut and added the cleaner. It happened right after we had placed another driveshaft into the car to see if it got rid of the buzzing sound. I also felt a very uncomfortable shaking under accelleration as well which felt like a balance problem. We removed that driveshaft and placed the other one back in. Since the howl has returned, I am going to have this shaft balanced, and see if that helps.