Hi,
A club member claims his ‘‘kick-down’’ is constantly on; as
soon as he touches the accelerator, the gearbox shifts down.
The shift points on the BW66 is regulated by the adjustable downshift cable,
Bard…
The first step is to look at the cable’s connection to the gas pedal
linkages - there is threaded adjuster there. Crimped to the cable there
should be small ferrule - placed there when the cable was adjusted. The
clearance between the ferrule and the threaded adjuster should be 0,4
mm/0.01", and if incorrect; adjust to correct clearance…
If there is no ferrule, the best idea is to take the car to a transmission
shop for adjustments - cable adjustment is very sensitive, so ‘freehand’
adjustments is not really advisable. A shop will read fluid pressure to get
the correct adjustment, though it can be done DIY with the right equipment
and procedure…
If the ferrule is in place, and adjustments prescribed doesn’t work - other
faults may cause the anomaly. First; the connection of the cable at the
gearbox end should be checked. A plastic ferrule is pressed into the box,
and if loose; the cable adjustment is disturbed - depending on eventual
ferrule damage, cable might have to be changed.
Basically; the downshift cable adjustment ‘tunes’ the engine driven pump’s
pressure to the gearbox - the automatic operation is based on fluid
pressures. Operating the throttle pedal moves the cable, and valves in the
valve body reacts to pressure variations. This is the driver’s input; moving
the pedal tells the box what the driver wants - more pedal means more power
required - and the box will downshift to allow the engine to rev up for more
power.
There are three inputs to the box, all hydraulic. The engine driven pump
will alter pressure output with increased rpms. The downshift cable gives
the gas pedal position - and the governor, mounted on the box’s output
shaft, will tell the box about the road speed. These inputs combine in the
valve body to select the appropriate gear for the situation at hand - just
like a driver on a manual chose gears…
The fault is either with the cable/adjustment, the governor or within the
valve body - but there is no initial way to say where…
Frank
xj6 85 Sov Europe (UK/NZ)
Has anyone experienced this?-----Original Message-----
From: Bard Thomas Hesvik
Sent: Wednesday, August 10, 2016 8:06 PM
To: xj@jag-lovers.org
Subject: [xj] XJ6 Coupe; BW66 “kick-down”
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