[TR] TR6 Question

Randall tr3driver at ca.rr.com
Mon Nov 5 11:12:34 MST 2007


> What's the easiest way to tell if a TR6 has an overdrive  
> transmission?

Only sure way is to crawl under the car (or pull the tunnel) and check.  All
of the other indications might be present with no OD (if for example someone
has already done exactly what you are planning to do); or absent with OD
present (if for example someone installed an OD transmission but never got
around or didn't know to hook up the OD).

>  This will fit my TR4, no?????? 

Depends on what year TR6.  Early ones had A-type ODs and are fairly easy.
Up to you whether to change the front cover or not (the TR4A-6 front cover
is shorter for the diaphragm clutch and at least some people have reported
that the TOB carrier hangs up on the short nose).  Change the shift lever
(if you want), and speedo cable.   Not certain, but I think it's likely
you'll need to replace the 3 studs in the engine block, as the gearbox
mounting flange got thicker.  And of course hook up the electrics.  Don't
forget a relay, and I would suggest also a big diode to absorb the kickback
from the solenoid.

I believe the later J-type OD can be made to fit in a TR4, but will require
more effort.  Things like notching the frame rails, fabricating a rear
mount, etc.  Also the speedo drive ratio will be off by 11-12% unless you
open up the OD and change the gears.  Hopefully someone who has done this
can chime in with more details, like whether the angle drive is required and
what speedo cable to use.

Randall


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