Stuart,
The real problem is that your gears had been previously used in another
differential, where they developed a wear pattern. Unless the set-up in your
TD exactly duplicated the MGA relative placement of the ring and pinion, the
teeth are now meshing slightly differently, meaning that worn and unworn
areas of the faces are now in contact with each other, even if the pre-load
was set up exactly to specification. This uneven wear is the source of your
noise. In my experience, this will not cause the gears to fail. You will
have to learn to live with the noise, or get a louder radio or muffler {G}.
Completely silent rear end conversions using previously installed gears are
a virtual impossibility, I'm afraid.
Lawrie
British Sportscar Center
-----Original Message-----
From: Stuart Keen <simbafish@home.com>
To: MG <mg-t@autox.team.net>
Date: Wednesday, May 31, 2000 6:53 PM
Subject: 4.3:1 conversion
>Last February at a MG workshop, a used MGA 4.3:1 ring and pinion gear
>(also all new bearings and gaskets) were installed in my MGTD. Trial
>fits were made, grinding accomplished as well as shims in place. It was
>supposedly properly done, though no special tools were used, other than
>a feeler gauge. Over 30 conversions have been done by the workshop.
>
>The results are less than satisfactory and I would appreciate opinion if
>my MGTD is likely to run into problem. When I drive under constant
>unchanging acceleration, there is virtually no whining/singing. When I
>completely remove my foot from the accelerator, again there is no noise.
>HOWEVER, when I gradually release the accelerator pedal when slowing
>down, such as coming to a stop light, there is a definite audible
>whining. If I attempt to maintain CONSTANT SPEED going up and down
>rolling hills (such as Rt 81 thru Tennessee and Virginia), when I back
>off the accelerator while going down the hill, the whining is rather
>loud. To avoid this, I race down the hills so that the accelerator pedal
>is constant and the ring and pinion gears engaged, not "floating" in
between.
>
>I was at the Carlisle Import Show a couple weeks ago. I was told that
>the problem is improper preload adjustment. One called it a "light load"
>adjustment. Another said it was a bearing placement, another thought it
>was placement of the pinion. My concern is whether or not this noise is
>doing damage and if it should be fixed? If it needs to be corrected,
>where can this be done reasonably? There is no local garage with
>experience with this conversion and therefore I would have to ship the
>rear end (a real bummer). Any suggestions would be appreciated.
>
>Stu Keen
>Venice, Fl
>1951 MGTD MKII
>
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