On 5/2/2024 11:40 am, Mighty Mouse wrote:
>
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https://auslink.info/video/range_rover.mp4
Saw it a month back when he first released the video.
>
> The intricacy of the gearbox surprised me..
Simpler and way more flexible than it would be if it were fully hydraulic.
> all those fluid channels with springs, levers, etc.,.
Actually simpler vis a vis the fluid channels than a fully hydraulic
controlled trans. All the required "circuits" are there, they just
aren't all fully hydraulic any more. A good example is the governor valve.
https://www.freeasestudyguides.com/transmission-governor.html
In the past the governor weights controlled governor pressure according
to how fast the governor was turning. That functionality has been
replaced by the Vehicle Speed Sensor and the governor pressure solenoid.
The trans computer gets the road speed signal from the VSS and varies
the PWM signal to the governor pressure solenoid. Note the VSS was
already present in the car supplying road speed signals to other devices
such as the speedo, trip computer, etc. The VSS signal can be checked
for rationality against other similar signals such as the wheel speed
sensors at each wheel assembly. Simpler and way more flexible!
> and also the short lifespan of it.
The issue is not one of lifespan, it is one of *servicing*. Trans these
days use a lifetime fluid - but don't believe it. The problem with full
electronic over hydraulic trans is that those solenoids fail - and most
of the time they fail due to gummy trans fluid. Trans fluid has a high
detergent component in it. When that breaks down over time, and it will,
the fluid goes gummy with a varnish, especially if you load the trans up
a lot. That varnish layer coats the plungers, solenoids and the like -
makes them stick. Doesn't do a lot that's good for shift timings. When
you change the trans fluid, you rejuvenate the additives in it and it
cleans off the varnish buildup. Best not to let the varnish build up so
change the fluid frequently.
The 4 speed Aisin (Toyota) trans in the Swift is good for 500,000
kilometres and more if not abused and fluid changes are regular.
> no wonder manufacturers are moving to CVT's
CVTs tend to have a shorter lifespan.
I subscribed to his channel long ago - an interesting character. His
stepmother ain't too foul either! ;-)
--
Xeno
Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)