On 10 Jan 2011 at 20:18, Grant Buss wrote:
> I don't want to take the trans apart,unless it is
> a simple fix. I think you can't buy the part.
Whether it is a simple fix depends on what the problem is. One might
way that anything you do with the gearbox isn't simple. But it
really depends on what the problem is.
That the speedometer works at all and is more or less right at 60
suggests it is something inside the speedometer. I don't see how it
would work at all if any part of the speedometer drive were broken.
That being said, there might be a relatively easy fix (compared to
pulling the gearbox out). The speedomoeter is driven by a plastic
gear on the output shaft. This turns a worm gear on a shaft held
into the rear gearbox extension by a removable socket and into which
the cable goes. You might be able to see and even replace some of
this if something is broken.
Spitbits.com has the plastic output shaft gears for at least the
later Spitfire and GT6 boxes.
You need to remove the vertical dashboard support, the front carpet
section, and the gearbox cover, all a bit of work but not hard. Then
you might be able to pull the worm gear holder out by removing the
pin bolt that holds it in place (located just above the cable input
hole). This might give you enough access to let you see into the
hole. With a small light you might be able to see if the gear on the
output shaft is broken.
If the gear is broken you can probably remove the rear extension from
the gearbox without pulling the gearbox out. Mind you, I've never
done it with the gearbox in place but I see no reason why you can't.
Remove the driveshaft bolts and the nuts which hold the rear engine
mount, then jack up the engine with a hydraulic jack and board under
the oil pan. Once the driveshaft flange is free you should be able
to remove the rear pulley. You should probably remove the shifter
from the top too jsut go gain working space. Remove the seven bolts
which hold the extension in place. Then with a soft mallet and/or
suitable drift you can knock the rear extension off the back of the
output shaft. Voila!
Assembly is the reverse of dis-assembly.
It's, ah, a lot of work.
--
Jim Muller
jimmuller at rcn.com
'80 Spitfire, '70 GT6+
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