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Re: trouble in reverse........od?

To: Triumphs <triumphs@autox.team.net>
Subject: Re: trouble in reverse........od?
From: "Power British Performance Parts, Inc." <britcars@powerbritish.com>
Date: Tue, 27 Apr 1999 11:15:27 -0400
References: <199904271024_MC2-7391-944A@compuserve.com>
Dave Massey wrote:

> Gary,
>
> How do you know overdrive is not working?  Maybe it is working all
> the time?  This sounds like the symptom you get when the clutch
> gets stuck in the O/D position.  Check the speed vs rpm equation
> and see if the you get 25 mph/1000 rpm in fourth.  If so you are
> stuck in O/D.
>
> What to do about it?  I dunno.  One time this happened to us and we
> took a soft faced hammer (Rawhide) and rapped on the O/D housing
> and the O/D resumed normal operation.  The second time it happened
> (different car) we did the same thing and it fixed it again but only for a
> while.  At this point in time I don't know what is wrong and wht the fix
> is.
>
> Perhaps someone else out there has some insight????
>
> Dave Massey
> St. Louis, MO USA
> 57 TR3 (no O/D)
> 71 TR6 (type J O/D)
> 80 TR8 (5 speed)
>
> ----------------------- Original message
> ------------------------------------
> Just being a nice guy............loaned my 6 to a friends son for the prom
> and..........just thought it would be good to jump at the chance at
> interesting the younger generation in lbc's.
>
> Anyway.......backed it our of the garage and found that the car would not
> back up very easily.  Kind of a binding/braking feeling.  Then something
> would give quickly (like a snap or something) and it would back up more
> easily but still felt braked.  I then took it on a run and everything
> worked
> well in all four forward gears.  However switched on the overdrive and it
> did not work.  could not get it to work at all during the 10 minute drive.
> Back home again and did the reverse thing and same problem.
>
> I have all the cut out switches hooked up properly.  Although am not sure
> they all work.  I am pretty sure the forward gear cut out switches work but
> maybe reverse cutout did not work and the kid used overdrive and backed up
> during the evening.
>
> Question is:
>         Has anyone else had this experience?  Is this a trashed overdrive
> or
> tranny (reverse gear)?  Rearend? Just a switch thing, and od may be stuck
> in
> the ON position?
>
> I just finished (over the winter) rewiring the od properly, getting a new
> solenoid, new tranny plastic cover......everything was working perfectly!!!
> :(
>
> Oh well.......maybe I peaked an interest in lbc's in a couple young kids!
>
> any suggestions would be very helpful!!
>                 Gary, Frances Nafziger
>                 Wellman, Iowa

I just re-read the original post, and I agree with Dave.  The symptom does seem 
to be
an overdrive that is partially engaged.  I would venture to guess that this is a
J-type from a post '74 '6.  The J uses a normally open pressure relief system, 
sort of
the opposite of the A.  The  J solenoid closes the bypass allowing pressure to 
build
in the system ultimately engaging the OD.  The passages in the housing are very 
small
and there are a lot of O-rings in a J to break down and clog up one of those 
passages,
inhibiting the bypass function - it is a fairly common problem with the J-type.

Disconnect the electric lead to the solenoid and to a test back-up first to be 
sure
the problem is not electrical.  If reverse is still baulky with the solenoid
disconnected, test to see if reverse works normally when there is no pressure 
in the
OD hydraulic circuit.  Drain both the trans and OD and run the car in reverse 
in your
driveway with no oil in the gearbox - a short run up and down the driveway 
won't hurt
anything.  With no oil, the OD pump cannot build any pressure.  If reverse is 
OK this
way, then the problem is constant pressure in the OD and you've probably got a
blockage somewhere in the OD bypass.

Good luck and don't forget to refill the 'box afterward!

Regards,

Brian Schlorff    '61 TR-4     '64 TR-4     '72 TR-6     '79 Spit
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