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RE: Overdrive

To: "'Huw Upshall'" <hupshall@wolfenet.com>
Subject: RE: Overdrive
From: Peter Cebalo <cebalo@NthShore.govt.nz>
Date: Tue, 24 Nov 1998 12:35:48 +1300
BY FAR the easiest method is to find a complete transmission. I
converted mine the hard way by adding it to the existing transmission. 

If you wish to use your existing tranny, there will be problems finding
some of the parts, especially the top cover and remote assembly. If you
choose this method, you'll probably want to replace all the bearings and
syncro rings,layshaft etc etc. ends up costing lots but you end up with
a better unit.
If you do it this way you'll need: ( minimum )

"J" type OD - ( careful - different types, some of the rear casings are
different - some don't have the upper mounting holes e.g. 73/74 Spifire
Mk IV - 3 rail type , TR6 , TR 2500 saloon, Dolomite, Stag - check the
speedo gears too... )
new mainshaft
rear main shaft bearing ( unless it's loose :-) likely you'll damage the
old one taking it off the shaft - hey, replace  them all ) 
top cover 
inhibitor switch gear
remote assembly tower ( not available new )
adapter plate ( sometimes difficult to get )
oil pump cam and circlip ( if these didn't come with the OD , also
expensive )
gaskets ( tranny to adapter, adapter to OD )
mounting plate
rubber mounting assembly ( best to use a new one )
speedo angle drive ( these are really expensive - about US$90 ? - I have
some of spares )
speedo cable
shortened propshaft ( get it balanced at the same time - check the UJs )
OD gear change lever (not available new )
OD switch, knob and cap ( available new )
wiring ( use the live wire from the reverse light )

Put you off yet ??

Finding a COMPLETE OD Transmission in good condition could be a
challenge. Always check the magnetic drain plug on the transmission for
fragments of metal and the colour of the fluid. If possible remove the
top cover and look for wear on the teeth and syncro rings. Condition of
the OD is hard to tell without separating the front and rear casings and
inspecting the clutch surfaces. If you remove the sump plate on the
bottom of the OD, you can check the magnetic strip on the plate for
obvious problems. Hard to check the solenoid even by applying 12 volts
to it - if it doesn't click - probably faulty - even if it clicks it can
still be faulty... 

Hope this helps

Peter Cebalo

Auckland, New Zealand

73' Spitfire Mk IV ( with "J" type overdrive added 'the hard' way )



 


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