[Healeys] Overdrive Ideas Needed

Earl Kagna kags at shaw.ca
Fri Apr 30 13:01:06 MDT 2010


Mark:

Many of us are running Redline MTL or MT90 in out gearboxes with no 
problems.  In fact, many of us have discovered that these oils which are 
designed for use in 'manual transaxles' produce a better feeling shift in 
our old-tech gearboxes without compromising the overdrive cone clutch in any 
way.  Personally, I've run MT90 in several gearboxes for many years - it's a 
synthetic oil that is equivalent to an approx. 30 - 40 weight 'dinosaur' 
oil. (MTL is slightly lighter).

Sorry to disagree with Jim - I doubt that your problem is the oil.  The 
overdrive solenoid is a dual coil item.  Are you sure that the holding coil 
is working correctly - if not, the overdrive will engage on the pull-up coil 
and then drop out on it's own - not necessarily right away.  Otherwise I 
agree with the lister who recommended that a pressure reading be taken.  If 
the pressure is marginal, overdrive operation can be erratic - depending 
upon oil temperature, gremlins, etc.

If pressure is low, then you have a whole new dignostic procedure to get 
through to fing out why.

Incidentally, I've found that most of the overdrives that I've worked on 
need to be adjusted slightly beyound the drill-in-the-hole setting because 
of wear in the operating valve mechanism - usually the valve itself.  It's a 
touchy adjustment - the solenoid has to drop out the pull-up coil, or you'll 
burn it out quickly.

Earl Kagna
Victoria, B.C.
BT7 tri-carb
BJ8

----- Original Message ----- 
From: "Jim LeBlanc" <jim_leblanc at yahoo.com>
To: <healeys at Autox.Team.Net>; "Mark LaPierre" <lapierrem at sbcglobal.net>
Sent: Friday, April 30, 2010 10:46 AM
Subject: Re: [Healeys] Overdrive Ideas Needed


Mark,

I have always run 30 weight in my gearbox with no problems. It shifts better
than when using 40 or 50 weight. Never, ever tried heavier oil. Often I put 
a
quart of ATF to help preserve the rubber parts.

When I read your note, I got the impression you are using oil that is way 
too
heavy. Before taking the deep dive into the internal parts, try lighter oil.

Best Regards,

Jim LeBlanc
1956 100-M


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