[6pack] OD Inhibitor Switch

[Rick Patton]

Hi Vance,

As Aaron mentioned earlier I have exactly what you've been looking for. 
It's a little solid state black plastic box with a series of colored 
LED's. Mounted out of sight under the dash the led's are for trouble 
shooting and status. And as long as things work properly you don't need 
to see the lights. I purchased it from a fellow in Britain a number of 
years ago after seeing it mentioned in these Forums. At the moment I 
can't recall his name and he may not even offer them anymore. It does 
make the overdrive behave like the Volvo.

You do need to replace the original OD switch with the supplied 
momentary switch.

Here's what it does:

In an overdrive gear a tap on the switch engages OD and another tap 
disengages it.

It automatically drops out of overdrive whenever you shift out of an 
overdrive gear. So as you shift from third OD to fourth it automatically 
drops OD until you engage it. Same when downshifting.

Just the opposite of the above is that you can hold the switch and it 
will not drop out between overdrive enabled gears.

The wiring is color coded to match the TR6 so it's mostly a matter of 
plugging in bullet connectors.

Although my TR6 is a 75, it is set up with an overdrive enable switch on 
second gear like the earlier TR's. I like to run the car hard through 
the gears and before installing this control would find myself power 
shifting from redline into second gear OD because I'd forgotten to shut 
of the column switch. Hitting a gear hard and having it slam into 
overdrive gives you that sinking feeling wondering if you've just smoked 
the OD, not to mention the looks you get. It's now fool proof or at 
least this old fool can't make that mistake any more. By the way that OD 
is pretty darn tough!

In addition to the column mounted switch, the walnut gear shift knob has 
been replaced by a Hurst knob with a momentary push button that also 
works the OD. Driving in traffic you can happily use that second gear 
OD! Tap the button it's in and tap it again and it's out. I absolutely 
love it. Although not required, a gear shift button makes it that much 
better.  I use the OD more than ever now. Here are a couple pictures of 
the shifter with the button:

http://topshamautoparts.com/tr6/gearshiftknob.jpg

http://topshamautoparts.com/tr6/gearshiftknob1.jpg

If you add a selector switch the same shifter button can be 
multipurpose, use it for other neat things like a hill holder / line 
lock or, for the really go fast guys like Al, Nitro!  If anyone is 
interested I will see if I can find the supplier's name. The controller 
was a bargain around $100 compared to the knob about $60!

Just came in from shoveling snow off the roof of the Garagemahall.

Rick Patton
Brunswick, Maine
75 TR6sci
74 TVR 2500M
http://pattonmachine.com/