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overdrive question - to declutch or not on o/d shifts?

To: british-cars@autox.team.net
Subject: overdrive question - to declutch or not on o/d shifts?
From: "Christopher A. Kantarjiev" <cak@parc.xerox.com>
Date: Thu, 26 May 1994 16:34:34 PDT
        Which makes me ask - what is the consensus on whether to declutch
        on shifting the o/d in or out? 

I doubt you'll get a concensus. I've read about as many
articles/manuals on each side. I finally decided, after thinking about
how they work, that it depends on the unit itself: the very late
production A type in my TR4A shifts essentially instantly, but the D
type in my GT6+ takes about half a second or more to engage. I figure
that the D type is taking a fair bit of time to build pressure for
various reasons (apparently design, since I checked all the clearances
last summer when I rebuilt it) and thus there must be a period of
clutch slip while the overdrive clutch is moving from one side to the
other. Since the failure mode on the D type usually is clutch material
wearing completely away, I try to minimize the clutch slip, so I
declutch for shifts with it. I don't bother on the A type.

'Struth, I'm not sure it matters.


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