The_Doc Posted December 29, 2015 Report Share Posted December 29, 2015 Dear All During my Tr4A restoration project, I have come up against a dilemma. A-type over drives seem extremely expensive and so I'm contemplating fitting a J-Type over drive instead. I'm guessing I just need to change the main shaft of my Tr4A non-overdrive gear box to accomodate the J-Type. Other then that are there any other expensive mods I shopuld be worried about? Also would it be easier to just find an late Tr6 or Dolomite sprint gear box with the overdrive that I can just slot into my car or would this require more substanial changes to my Tr4A, i.e. clutch plates etc.? Thanks Adam Quote Link to post Share on other sites
RobH Posted December 29, 2015 Report Share Posted December 29, 2015 Very similar topic discussed only recently Adam which might answer : http://www.tr-register.co.uk/forums/index.php?/topic/54592-j-type-overdrive/?hl=overdrive Quote Link to post Share on other sites
Guest Posted December 29, 2015 Report Share Posted December 29, 2015 My TR3A has a TR6 'box + J-type OD. Works perfectly well. Go out and find yourself one. Menno Quote Link to post Share on other sites
Andrew Smith Posted December 29, 2015 Report Share Posted December 29, 2015 (edited) Adam,You will also need the adaptor plate, a replacement gearbox top cover with isolators (or your top cover drilled to accept them) and also an OD wiring loom, OD column switch, OD escutcheon cover and a longer speedo cable.TR6 A Types are out there if you are patient. I recently bought one on eBay off a 69 TR6 (correct serial numbers and 22% ratio) for £99. Pete Cox has inspected it and very little was needed other than a good clean out and new seals. It tested at 400 psi.It's eventually worth it if you can keep on looking.Hope that helps.CheersAndrew Edited December 29, 2015 by Andrew Smith Quote Link to post Share on other sites
peejay4A Posted December 29, 2015 Report Share Posted December 29, 2015 You'll need a rear gearbox mount adapter too. Quote Link to post Share on other sites
Andrew Smith Posted December 29, 2015 Report Share Posted December 29, 2015 You'll need a rear gearbox mount adapter too. I knew there was something else! Cheers Andrew Quote Link to post Share on other sites
TriumphV8 Posted December 30, 2015 Report Share Posted December 30, 2015 TR6 A Types are out there if you are patient. I recently bought one on eBay off a 69 TR6 (correct serial numbers and 22% ratio) for £99. Wonderfull price, congratulations, unbelievable here in Germany. We can be happy to grab a naked J-OD from a Volvo for that price! Quote Link to post Share on other sites
AlanG Posted December 30, 2015 Report Share Posted December 30, 2015 (edited) I knew there was something else! Cheers Andrew And a right angled speedo drive and a rear gearbox mounting kit Alan. Edited December 30, 2015 by AlanG Quote Link to post Share on other sites
peejay4A Posted December 30, 2015 Report Share Posted December 30, 2015 I refer the honorable gentleman to the answer I gave earlier Quote Link to post Share on other sites
John Morrison Posted December 30, 2015 Report Share Posted December 30, 2015 (edited) Hi Adam,Nothing that cannot be overcome fitting j type into your car.Probably every answer in these hallowed pages, but don,t phaff about building boxes and doing conversions etc,Find a. Tr 6 box and J type, probably couple hundred quid, and you are on your way.Folk on this forum will gladly guide you through steps such as rearmount, wiring etc, (my advice would be go with the gearbox lever switch, feels so natural,Just keep on asking, where abouts are you?John Edited December 30, 2015 by john Quote Link to post Share on other sites
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