AndyW123blue Posted August 10, 2015 Share Posted August 10, 2015 Hi allNew to this forum, just started the restoration of a mk1 gt6, currently has a non overdrive gearbox. Want to fit an overdrive box. Looking on eBay there's a few types A, J etc can anyone give me a pointer on if there's a wrong type. Also is there anywhere that sells reasonable priced overhauled units. Other than a shorter propshaft and a modified mounting plate is there anything else to consider.ThanksAndy Quote Link to comment Share on other sites More sharing options...
yorkshire_spam Posted August 10, 2015 Share Posted August 10, 2015 Gearbox mainshaft to be changed as well I think. Quote Link to comment Share on other sites More sharing options...
Clive Posted August 10, 2015 Share Posted August 10, 2015 Indeed. Plus the gear change linkage needs to have an extra "wing" so you can fit an inhibitor switch. And teh overdrives usually come needing the appropriate adapter plate so they mate up to your gearbox. And a solenoid....... not forgetting the longer od speedo cable and expensive angle drive.It means a gearbox strip to fit the od mainshaft, so is not to be undertaken lightly.oh, and a part often forgotten is the cam on the mainshaft to drive the od oil pump.And the OD unit you require is a D type.Honestly, it is much much easier to buy a complete package. Quote Link to comment Share on other sites More sharing options...
Piero franchi Posted August 10, 2015 Share Posted August 10, 2015 reading the guys first post,he says he wants to fit an overdrive box, I am reading this as a compleat box inc overdrive unit.I dont think hes wanting to add a overdrive unit to his own gearbox Quote Link to comment Share on other sites More sharing options...
Piero franchi Posted August 10, 2015 Share Posted August 10, 2015 you will need to right ratio diff to suit the overdrive Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted August 10, 2015 Share Posted August 10, 2015 There is also the wiring to consider and relay, but this isn't all that much of an issue, as it's just a couple of wires. I seem to remember the overdrive wiring on my converted Vitesse is actually the wire from a telephone! Quote Link to comment Share on other sites More sharing options...
thescrapman Posted August 10, 2015 Share Posted August 10, 2015 Andy90% of the gearboxes available that are suitable for your GT6 will be 3-rail with D-type overdrive.They will be boxes sourced from a GT6 or a Vitesse. One from any type of Spitfire is not suitable as a complete unit swap.Nor do you want a gearbox from a 2000 / TR / Stag, either A-type or J-type, unless you intend to modify your chassis (there is a thread going elsewhere on the forum about fitting a Dolomite Sprint box to a Spitfire, same gearbox.)You can also fit an 1850 dolomite box, either earlier or later types, they account for the other 10%. Later ones need a different clutch plate.No other Dolomite box is suitable.CheersColin Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted August 10, 2015 Share Posted August 10, 2015 Should add that the latter 1850 gearboxes (single rail with fine spline input shaft) are not a direct fit as the GT6 bell housing doe not properly fit the single rail casing and the gearbox is 1" longer meaning a special, shorter than standard propshaft is needed, plus a very tight fit with chassis/tunnel. The internals can be built into a 3 rail casing which solves the bell housing issue but not the length. Various other non-standard combinations are possible.....Nick Quote Link to comment Share on other sites More sharing options...
AndyW123blue Posted August 10, 2015 Author Share Posted August 10, 2015 Hi Thanks for all of the replys, so I guess it's a d type gearbox. Its a complete swap out not too worried about the electrical bits. More about the gear ratio and getting something that fits!Andy Quote Link to comment Share on other sites More sharing options...
AndyW123blue Posted August 10, 2015 Author Share Posted August 10, 2015 Anyone know where I can get one? Quote Link to comment Share on other sites More sharing options...
AndyW123blue Posted August 10, 2015 Author Share Posted August 10, 2015 Anyone know where I can get one? Quote Link to comment Share on other sites More sharing options...
Royboy66 Posted August 10, 2015 Share Posted August 10, 2015 Hello Andy ! Great choice of Triumph !! 😀My mk1 had no Overdive when I got it , It's a very worthwhile conversion. I converted mine by having my non overdrive propshaft shortened, I took a bit of time to get all the bits I needed together, ie, rear mount+ plate, angled speedo drive, column stalk, the overdrive gearbox I got hold of a working second hand unit just to get me going. Once all fitted and working I then steadily changed parts for better or new until I had a reliable set up. What stage are you at with the car? Do you need to convert it yet? Is it a runner? Any pics ? Regards Roy 😎 Quote Link to comment Share on other sites More sharing options...
Richard B Posted August 10, 2015 Share Posted August 10, 2015 Quoted from AndyW123blue Anyone know where I can get one? Bay of evil... 😀Anywhere from £125 for a tired O/D gearbox to £600 for a complete package from an eBay trader.Quoted from Piero franchi you will need to right ratio diff to suit the overdrive He's right! 😎If you have a 3.27 that will be long legged for a MkI 2000 engine, Motorways and Autobahns.Consider changing to a 3.89 (overdrive GT6/Vitesse differntial, also Spitfire MkIV) or a 3.63 (as fitted to Spitfire 1500).The 3.27 will be sellable as they go well (bit weak) with a 2.5 engine in a GT6/Spitfire.Use James's site to workout comparative to speedshttp://www.mintylamb.co.uk/gearspeed/ Quote Link to comment Share on other sites More sharing options...
Clive Posted August 11, 2015 Share Posted August 11, 2015 If your pockets are deep and you just want peace of mind, Mike Papworth should be able to help. He has a good reputation etc, Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted August 11, 2015 Share Posted August 11, 2015 Seconded - Mike Papworth really is the man for gearboxes etc. Quote Link to comment Share on other sites More sharing options...
AndyW123blue Posted August 11, 2015 Author Share Posted August 11, 2015 Thanks, I'll keep an eye on eBay. I only got the car a few weeks ago and have only managed to get the interior out so far as I'm on a family holiday now which is getting in the way! Going to completely strip it down and rebuild everything. Hopefully going in for a re spray around December / January time. I'll try Mike papworth if I get stuck.The throttle stuck when I was driving it. It redlined and has now developed a knock so the engine will need a bit of work other than that the bodywork apart from the bonnet seems pretty sound.I can't post a picture as apparently there too large.Andy Quote Link to comment Share on other sites More sharing options...
Richard B Posted August 11, 2015 Share Posted August 11, 2015 I use a program called "Shrink Pic" to reduce the size. Other options are available.If you are not in a rush then I'm sure you will find a suitable gearbox. Quote Link to comment Share on other sites More sharing options...
efp Posted August 11, 2015 Share Posted August 11, 2015 +1 on consulting Mike Papworth. Not cheap but a fount of knowledge and a straight guy in my experience. Quote Link to comment Share on other sites More sharing options...
Guppy916 Posted August 11, 2015 Share Posted August 11, 2015 I used a guy called Tony from Ixworth Suffolk , for my mk3 GT6 gearbox work I have a 2.5 lump triple 40's J TYPE O/D 28% up rated for motorway use he sorted my diff aswell can't praise him enough,, pm me and I'll give you his contact details Quote Link to comment Share on other sites More sharing options...
stomp Posted January 3, 2018 Share Posted January 3, 2018 Hi , I was wondering if anyone could send me the details for Tony Ixworth. Looking to upgrade my GT6 mk1 gearbox to overdrive. Kind regards Dave Quote Link to comment Share on other sites More sharing options...
chunky63 Posted January 3, 2018 Share Posted January 3, 2018 There is also the mod needed to the floor pan to clear the speedo angle drive and access to the propshaft bolts. The cover plate also needed, see item 28https://www.canleyclassics.com/triumph-gt6-mki/ii-d-type-overdrive Quote Link to comment Share on other sites More sharing options...
DanM Posted January 3, 2018 Share Posted January 3, 2018 The aforementioned Tony is selling some of his overdrive boxes to reduce stock on ebay look for seller t4sport6 Quote Link to comment Share on other sites More sharing options...
Steve P Posted January 3, 2018 Share Posted January 3, 2018 That would be TLD wouldn`t it?.S Quote Link to comment Share on other sites More sharing options...
stomp Posted January 3, 2018 Share Posted January 3, 2018 Thanks for the replies, it's much appreciated. Ill have a look 😎 Quote Link to comment Share on other sites More sharing options...
thescrapman Posted January 3, 2018 Share Posted January 3, 2018 Do a search for Tony Lindsey Dean or Kingston Sports Cars in Ixworth and it will bring up his phone number.I have purchased one of his boxes a couple of weeks ago.It is almost all new parts in the gearbox, a fully recon J-type overdrive from ORS. Looks a very nicely put together bit of kit. Can certainly see why it was what it cost.He offers a number of options, using either type of input shaft, different 2nd gear types, D or J type overdrive. Had a good look at the boxes when I went to pick it up.CheersColin Quote Link to comment Share on other sites More sharing options...
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