Photo at right: Broken selector switch after removal and disassembly
into its two halves.
Description and photos on this page courtesy of Dennis Altman
Symptoms and Diagnosis
Dennis Altman reports that he
started having problems with
his transmission reading R when in D every now and then. Over a period
of months this progressively got
worse until it would read
P-D-R-#-R-D-2-…rapidly
for about 10 seconds, then calm down. Dennis reports: "It
took longer and longer to calm down before I finally got an ETM and
diagnosed it
as the “XYZ” switch on the left side of the trans, on the input shaft
from the
shift cable to the trans. As you select
gears on the shifter, the cable rotates the shaft that goes through the
switch
into the trans. The switch has 5 micro
switches, but only 3 are used. The 3
switches send a binary signal to the trans computer to tell it which
gear
you’ve selected. There is a breather
tube on the top of the switch, routed to the engine bay, mine wasn’t
connected
and the switch injested water/gunk and the switches started sticking,
sending
false signals to the computer. The
switch finally gave up the ghost, and the car was dead, the computer
thought it
was in R, so no start, and it wouldn’t let the key out of the ignition."
Switch Description, Sources and Possible
Repair/Rebuild Method
Dennis reports "I ordered a new switch from Atlantic
British, they knew
exactly what I meant, (dealer took 15 min of explaining to figure it
out) and
got it to me in 3 days (thanks guys).
After he had finished replacing it (see procedure below), out of
curiosity Dennis drilled out the aluminum rivets
holding the old switch together, and about ½ pint of water
dribbled out of the
little thing along with a bunch of black mung and gunk. "It might have
been cleanable, but there are 2
little pins on the shaft collar that rotate the switch plate that broke
off on
mine, so it’s dead (might try to fix for a spare). The switch is sealed
with a rubber gasket and
comes apart cleanly, so if yours is just acting up, you might be able
to save
it by cleaning, and bolt it back together." (See photos above and below
of the dismantled switch assembly).
Close-up photo of dismantled
switch. Breather tube connection is at lower right of photo where wires
come out.
Procedure for Replacing the Switch
Dennis reports "The swap out was simple. Remove
the cotter-pin from the shift
cable
adaptor, -DON”T MESS WITH THE SETTING –the 10mm jamb nut and the barrel
nut/pivot!!!-----(ask me how I know this..)the nut from the shaft lever-14mm I think, and one nut/one bolt,
again
12mm, that hold the switch to the side of the trans. All will be clear
and simple when you crawl
under and have a look (see photo below). I left the
breather tube in place, to re-attach, but the new one came with a new
tube,
already attached-must be a common problem. My trans showed other signs
of a prior removal/install (other
wire
connectors not mounted on their brackets, zip-ties…) so the lazyness of
some
anonymous mechanic cost me $350-check yours if your switch is acting
up, or
even if it’s not it’s a cheap save!
View of selector switch and
cable attachment from under the vehicle.
"The new switch went on exact reverse of the old
one. I taped my new breather tube to the
bottom of the old one, and used the old one to pull the new one up into
position.
Bolt the switch into place before you reconnect the cable. To re-adjust
the
cable length, I put the shifter in P, rotated the input lever to P and
adjusted till the holes
lined up, there is play in the shifter to make sure you can get
positively
into gear. Move to first gear
re-check fit, then re-install the cotterpin. The switch rotates on its
mounts about 10 degrees, the shop manual specifies a tool/jig that
bolts on,
fit a pin in a slot and rotate, dangle chicken bones and chant…..I put
it in
reverse (it read park) and turned the switch until I heard the mirrors
auto-dip.
Tightened it down, crawled inside and shifted
through the gears a few times to check all is well-the gearbox fault
self cleared so no expensive trip to the dealer this time. No problems
for
over a month."
