Jim,

Your several message in this thread so far are much appreciated. I'm not
exactly visualizing everything just yet, but then I have no idea what these
things look like inside. (How do you?) Spool valves, pumps, relief valves,
heat exchangers, front adapter, clutches and reverse clutches, hydraulic
circuits - but I do find it all very intriguing!

Testing pressure - as in screw a manometer of some type into the 3/8 plug
hole? A manometer of _what_ type? Prob'y easier to ask mechanic to do it for
me.

When I had a new shaft made a few seasons back, it was built twice (at a
machine shop) because mechanic wasn't happy with tolerances first time.
Finally got it to 4/1000, I think, and then 7/1000 installed but this was
out of the water. Mechanic said that was a little over tolerance, but that
it all slid together so effortlessly that he considered that a very good
sign, and opined that fiddling with it further would probably not be
advantageous. Sort of "the enemy of 'good' is 'perfect'" philosophy. Anyway,
it seems fine - there was minimal perceptible vibration with the original
shaft, same now. I've had my hand on the stuffing box while someone else
piloted the boat, up on plane (16 knots - whee!!!), and it's as smooth as
silk (if that means anything).

Thanks again.

====

Charles T. Low
- remove "UN"
www.boatdocking.com/BDPhoto.html - Photo Contest
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

====

"Jim Kelly" wrote in message
...
...
When you move the selector to forward or reverse, the spool valve directs
the
fluid to the proper clutch. There should be at least 120 PSI present at
the
spool valve in all selector positions. The internal pump is actually
capable of
much higher pressure but it is regulated by a relief valve built into the
end of
the spool valve. The relief valve directs fluid to the heat exchanger.
There
are test ports for checking the pressure. Remove the 3/8 plug on the top
of the
case next to the port leading out to the heat exchanger. Warm and idling
you
should read at least 120 PSI in all selector positions.

To check reverse pressure, there is a smaller plug either next to the 3/8
plug
or on the front adapter on the top of the case depending on the vintage
(some
models have both plugs in which case you can use either). Warm and idling
in
reverse, you should again read a minimum of 120 PSI. This verifies that
the
reverse clutches in the front of the transmission are receiving full apply
pressure.

There is no separate test port for forward apply pressure since the
hydraulic
circuit for forward is through the center of the shafts and not the case
as it
is in reverse. If you have the specified pressure at the 3/8 test port
while in
forward, it is pretty safe to assume that the forward clutches are
receiving
full apply pressure due to the design of the circuit.

Charles,
Velvet Drives are relatively simple transmissions. I have rebuilt several.
The parts are readily available and comparatively inexpensive. The only special
tool required is a snap ring pliers for Eaton type rings. These rings have no
holes in them so standard snap ring pliers won't work. The coupling nut will
have to be removed and installed with an impact wrench but, if you do not have
one, you can get this done at any automotive repair shop. A good source for
rebuild kits and parts is Transmission Marine in Ft. Lauderdale. Anyone with
average mechanical skills should be capable of rebuilding these units.

A simple dial type pressure gauge can be used for checking the pressures. It
should have a range of at least 160 psi. You can buy one from industrial supply
houses like Grangier for less than $10.

"Charles T. Low" wrote:

Jim,

Your several message in this thread so far are much appreciated. I'm not
exactly visualizing everything just yet, but then I have no idea what these
things look like inside. (How do you?) Spool valves, pumps, relief valves,
heat exchangers, front adapter, clutches and reverse clutches, hydraulic
circuits - but I do find it all very intriguing!

Testing pressure - as in screw a manometer of some type into the 3/8 plug
hole? A manometer of _what_ type? Prob'y easier to ask mechanic to do it for
me.

When I had a new shaft made a few seasons back, it was built twice (at a
machine shop) because mechanic wasn't happy with tolerances first time.
Finally got it to 4/1000, I think, and then 7/1000 installed but this was
out of the water. Mechanic said that was a little over tolerance, but that
it all slid together so effortlessly that he considered that a very good
sign, and opined that fiddling with it further would probably not be
advantageous. Sort of "the enemy of 'good' is 'perfect'" philosophy. Anyway,
it seems fine - there was minimal perceptible vibration with the original
shaft, same now. I've had my hand on the stuffing box while someone else
piloted the boat, up on plane (16 knots - whee!!!), and it's as smooth as
silk (if that means anything).

Thanks again.

====

Charles T. Low
- remove "UN"
www.boatdocking.com/BDPhoto.html - Photo Contest
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

====

"Jim Kelly" wrote in message
...
...
When you move the selector to forward or reverse, the spool valve directs
the
fluid to the proper clutch. There should be at least 120 PSI present at
the
spool valve in all selector positions. The internal pump is actually
capable of
much higher pressure but it is regulated by a relief valve built into the
end of
the spool valve. The relief valve directs fluid to the heat exchanger.
There
are test ports for checking the pressure. Remove the 3/8 plug on the top
of the
case next to the port leading out to the heat exchanger. Warm and idling
you
should read at least 120 PSI in all selector positions.

To check reverse pressure, there is a smaller plug either next to the 3/8
plug
or on the front adapter on the top of the case depending on the vintage
(some
models have both plugs in which case you can use either). Warm and idling
in
reverse, you should again read a minimum of 120 PSI. This verifies that
the
reverse clutches in the front of the transmission are receiving full apply
pressure.

There is no separate test port for forward apply pressure since the
hydraulic
circuit for forward is through the center of the shafts and not the case
as it
is in reverse. If you have the specified pressure at the 3/8 test port
while in
forward, it is pretty safe to assume that the forward clutches are
receiving
full apply pressure due to the design of the circuit.