Steve Sage wrote,
>At medium to high speeds and rpms (above 4,000, usually), I get what I
>percieve as a "grinding" and or high speed "rattling" from what seems
>like the shift lever area of the trans. Here's what I know: the "yoke"
>that holds the driveshaft into the transmission seems sound with very
>little free play, and the U joints seem fine. The drive shaft can be
>turned 1/2 to 3/4 inch in either turning direction, by hand, before
>resistance is met. I've been told this is not necessarily abnormal and
>in any event wouldn't be causing the noise.
>A mechanic who has helped me a lot with the car told me there is a
"dust
>plate" inside the top cpver of the transmission that looses its screws
>after time and therefore causes rattling like I'm describing. I've been
>advised to remove a side plate on the transmission tunnel and either
use
>a clamp of some sort to secure the plate, or remove it all together.
>Looking at the shop manual, the only picture shown is for a Rootes
>column shift top cover but in any event, it shows an item called a
>"splash plate". Is this what's being talked about that is looke and is
>rattling? From the picture, this doesn't make sense unless all the
>screws holding the top cover down have come out!
>Shifting seems completely normal and at slower speeds there's rarely
any
>noise. The noise does occasionaly sound up at different RPMs. Sometimes
>it may be worse at 4,000 RPM and others at 4500 or 3500.
Just about anything that is loose on that trans could vibrate.
I would not be concerned about the u-joints, when they go,
you'll know it, and tired ones vibrate at a very low frequency.
The shifter assy itself is held via a spring loaded conical socket
peice, and 4 10/32 screws to the shifter cover. If these
get loose, or the plastic shifter ball is worn, the ball will
resonate within the socket.
The whole shifter assembly clamps several sheetmetal plates
to the tranny. If the cover is loose, all manners of sounds will ensue.
There is also a sheetmetal piece that runs the length of the shifter
cover. It has a bunch of small screws to keep itself from resonating.
When the cover gets loose, the tranny will loose oil pretty fast.
Also, the shifter rod itself will resonate if the bushes in the cover
are worn.
Later transmisions had an anti-resonant spring that loads the shift
rod mid-shaft. This wont even work if the bushes are worn.
Another posibility might be laygear bearing failure.
The 1/2 to 3/4 inch rotational play that you speak of will be gear
dependant, any gear but 4th or reverse will allow you to check
if the laygear bearings are snuffed. This is a rapidly deteriorating
condition, which could render the laygear unusable due to
bearing galling in the inner races of the laygear.
Ive got a couple of trannies about with dead laygears,
and its the curse of death for an alpine tranny as stuffing
a new laygear in an old box means lots of noise.
Steve, your in SoCal right?
If you are not too far, I'd help you look it over.
Jarrid Gross
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