Whine in diff - opinions please

[MP100]

Hi,
I had 3.73 diff gears plus new bearing kit installed in the LSD in my VYII Calais recently by a gear / diff specialist. After a few days I noticed a slight whine under light load from 80km/hr on, up to about 110km/h. The car has done close to 90,000km and before the 3.73 gears no whine at all.
I took the car back & was told that as a non-standard gear, the firm who makes these for Holden, Ford & Toyota ("Dana" it sounded like) may not agree to replace the gears.
They went on to say that they may need the car for seven days while they send the gears back to Dana. Apparently the 3.73 diff gears have less teeth, and they are thicker, which could cause the whine I am hearing. Apparently there is no adjustment or shimming that can be done to rectify this.
In all the searching I did on the forum I don't recall hearing of anyone having issues with whine when fitting 3.73 diff gears.
My understanding is that 3.73 diff gears were standard on some models of Commodore. When having the gears installed, they told me they would be putting in genuine Holden gears. Do this Dana company supply these to Holden?
Is it reasonable to expect some whine when 3.73 gears are fitted? The way I see it, this noise should be their problem - & I don't see why I should be 7 days without my car when the gears were fitted in one day (for $1150 for those interested). Sorry for the long post - your advice is appreciated.

[tuff304]

I just had 3.73 gears (new gears and bearings) fitted to mine and there is no whine at all at any speed. Even if it does take 7 days try and get it sorted sooner rather than later. Good luck

[SSV366]

I would check the backlash.

[Toddler78]

I wouldnt be too worried if it had a slight whine(my personal preferance).
My 3.9s had a slight whine at about 80km + has since had new bearings, seals and kazz centre (unrelated problem) and still whines slightly. I would think that it depends on the diff oil used as some are more viscus then others and offer better noise supprencnt quailities.

The gears can be and should be adjusted to get the right wear. this is acceived by painting the teeth on the pinion gear and rotating you can then see how well the teeth are meshing with the crown wheel, this is where the noise would most commonly occur. I would ashume that not many places especially ones that dont specialise in diffs would do this step.

The other reason for your whine could be when they replaced the pinion seal in the front of the diff housing they tightened the nut too much crushing the bearing (this was the problem I had when my pinion seal was replaced.

ps $1150 sounds a very good price to me for gears, labour and seal/bearing kit - bearing/seal kit is over $500 from memory.

[MP100]

Thanks guys your info was greatly appreciated. Passed on your comments, and got the car booked in for new gears and a bearing kit. Picked up the car yesterday, and all is good. The whine is gone and the after sales service could not be faulted. The work was done at a place called Gear Exchange Services, at No. 10 Long St, Smithfield. Some forum members may have encountered Jason at the drags, where he races his 420rwkw (I'm told) LC Torana with a cammed 308 in it. Thanks again :bow:.

[Da Burb]

Just as a side...I believe it's an incorrectly set 'pinion bearing preload' which causes a whine...not backlash.

[scoot1]

Whine can also be caused by mismatched gear sets, lapping in of gearsets is something to be considered when fitting new or used gearsets.

[clarkey62]

If its a real nagging whine its probably my wife:)