[TR] slow overdrive

Randall tr3driver at ca.rr.com
Thu Mar 12 15:09:47 MST 2009


> Is this indicative of anything specific.

While there are lots of things that could cause that, Bill, my first thought
would be to check the solenoid adjustment.  The "pin through the lever"
method given in all the books does not always work, and misadjustment can
cause slow engagement.

A quick test of this theory would be to drive the car at relatively low
speed and away from traffic with the tunnel out, so you can engage the OD by
pushing directly on the lever (with the hole in it).  If that makes it
engage promptly, then the adjustment is the issue.

The alternate method of adjusting the solenoid involves removing the plug
above the operating valve, and measuring how far the ball moves when the
solenoid is held at the top of its travel.  Unfortunately there is no clear
consensus on how far the ball should move for a Triumph, but I am inclined
to follow the Healey recommendation of 1/32".

More info at
http://www.buckeyetriumphs.org/technical/AOD/AOD4/AOD4.htm
(near the bottom)

While you are in there, inspect the ball itself for any signs of corrosion,
wear or damage.  If it is not absolutely perfect, replace it.

Beyond that; my next step would be to get a pressure gauge and see what it
had to tell me.  Low pressure for whatever reason could also cause slow
shifts.  Somewhere on the web there is an article by Del Border showing one
fix for low oil pressure.  Let me know if you would like a copy via email.

-- Randall



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