ronhatch Posted August 27, 2014 Report Share Posted August 27, 2014 Hi all, I am changing the standard gearbox to an overdrive box on 1962 TR4, has anybody got a picture or a drawing of the rear mounting adapter. Cheers Ron Quote Link to post Share on other sites
peejay4A Posted August 27, 2014 Report Share Posted August 27, 2014 (edited) If you're fitting an A-type overdrive you shouldn't need an adapter, it goes on the standard gearbox mount. If it's a J type you need something like this: http://www.moss-europe.co.uk/graphics/uk/instructions/211361X%20FITTING%20INSTRUCTIONS.pdf Edited August 27, 2014 by peejay4A Quote Link to post Share on other sites
ronhatch Posted August 27, 2014 Author Report Share Posted August 27, 2014 Thanks for the swift reply, I will check which type it is and hope it is an A type. Regards Ron Quote Link to post Share on other sites
Chris59 Posted August 27, 2014 Report Share Posted August 27, 2014 (edited) If your gearbox come from a saloon, you'll have some fun, as the rear casing is totally different. Edited August 27, 2014 by Chris59 Quote Link to post Share on other sites
peejay4A Posted August 27, 2014 Report Share Posted August 27, 2014 Chris makes a very good point. Do you know where the overdrive originated? Quote Link to post Share on other sites
ronhatch Posted August 28, 2014 Author Report Share Posted August 28, 2014 From a 2.5 saloon, oh joy ! Quote Link to post Share on other sites
TR 2100 Posted August 28, 2014 Report Share Posted August 28, 2014 (edited) Look at the positives. A saloon overdrive is a helluva lot better than no overdrive. Check out the mods you need. AlanR Edited August 28, 2014 by TR 2100 Quote Link to post Share on other sites
Lebro Posted August 28, 2014 Report Share Posted August 28, 2014 I have detailed everything you will need to do in another thread. I will post a link to it later today. Bob. Quote Link to post Share on other sites
Lebro Posted August 28, 2014 Report Share Posted August 28, 2014 Ron. Posts I have made on this subject: (FWIW) Posted 21 July 2014 - 02:06 PM I have a T2000 O/D box in my TR3. I re-drilled the flywheel to take a GT6 clutch complete, leaving the gearbox untouched. O/D had to be fixed anyway, so the specialists who did it upgraded to 8 springs, & the correct rear housing to fit TR rear gearbox mount. The rear flange (to propshaft) is different on the T2000 unit, but a TR one will fit with no problems, alternatively the flange could be modified buy elongating two of the holes, & turning some metal from the centre. (I used a TR flange) Remaining problem is the speedo drive ratio. TR is 2.5:1 reduction, T2000 is 3.5 - quite different. I used a T2.5PI MK 2 speedo innards to rebuild my TR speedo - this give the correct turns per mile of 840. Other solution is to have speedo re-calibrated. Bob. Posted 23 July 2014 - 09:04 AM The "least work" option is to use a t2000 / GT6 etc driven plate, a standard TR4 cover plate, & change the clutch release bearing, & carrier to TR type to match the cover plate (T2000 release bearing is expecting a diaphram type) I drilled flywheel to take GT6 diaphram cover plate, & so left the release as was (new bearing fitted though) You will still have to change or modify the rear flange, Change the O/D rear casing (or use an adaptor mount), & the speedo will need work to read anywhere near correct (see my previous post) The overall length of engine + gearbox + O/D will be around 5mm longer than standard, but the rubber mounts can be stretched to cope with this. The O/D isolation switches on the T2000 box only allow O/D in 3rd, & top, but that's not really a problem, you will have a switch for reversing lights if needed, & synchro on all forward gears. I am happy with my conversion. Bob. The rear casing of the overdrive is different on a saloon. in particular the means of supporting it on the chassis. A TR one has a horizontal surface on the underside to match up with the flat rear gearbox mount. The saloon type has two vertical mounts on the side of the casing. You can (I believe) buy an adaptor from Moss etc. Also the solenoid is mounted verticaly on the TR, & almost horizontal on the saloon. There are other differences inside, eg, operating pressures, number of return springs, & possibly size of accumulator. Also, the speedo cable drive is at a different ratio (3.5:1 instead of TR's 2.5:1), so the speedo will read slow. Bob. Quote Link to post Share on other sites
ronhatch Posted August 28, 2014 Author Report Share Posted August 28, 2014 Cheers Bob and all who offered advice, as usual the forum has come up with a solution. Regards Ron Quote Link to post Share on other sites
Dave Herrod Posted August 28, 2014 Report Share Posted August 28, 2014 My car came with a saloon gearbox with J type overdrive, thanks to a questionable "restoration" carried out for the previous owner. When I got it the speedo didn't work at all and I discovered that the nylon pinion drive was stripped. A chat with Overdrive Repair Services confirmed that the speedo drive gear in a saloon OD uses a different number of starts to that in a TR OD. ORS supplied me with the correct gear which, although it meant removing the innards, was pretty easy to fit. I could then use the correct TR speedo drive and did not have to re build or re calibrate the speedo. ORS also supplied me with the correct drive flange which, in my opinion, is a better solution than slotting or re drilling the saloon one. If you want, they will also re build an OD and upgrade it to TR spec. I finally had this done as the friction linings were damaged and since then the OD has worked perfectly for many thousands of miles. Do not be put off- it is a very feasible and worthwhile improvement. Dave. Quote Link to post Share on other sites
Lebro Posted August 29, 2014 Report Share Posted August 29, 2014 (edited) Ron. Yes - that is a point, my car is a TR3, & does not use a right angle speedo drive. I f you need to use one on the saloon O/D, then you will need one meant for a saloon, not a TR one, or the gears will not mesh. While walking the dog realised that above was total b0110ks ! As long as the saloon O/D speedo gear on the anulus (output shaft) matches the driven nylon gear which came with the O/D, then it will mesh OK. But at the 3.5:1 ratio. If you wish to use a standard TR speedo, then you would have to change the anulus (or gear on the anulus if it is a separate part) & the nylon driven gear to the TR type. This will then give the correct 2.5:1 ratio. Hardy Engineering, who re-built my O/D changed the rear casing for Healy 3000 one (same as TR), but to change the anulus (output shaft with speedo gear on) & nylong driven gear would have been a lot more money ! Dave. I was not aware that the speedo gear on the anulus alone could be changed ? Bob. Edited August 29, 2014 by Lebro Quote Link to post Share on other sites
Lebro Posted August 29, 2014 Report Share Posted August 29, 2014 See changes to my post above. Quote Link to post Share on other sites
Dave Herrod Posted August 29, 2014 Report Share Posted August 29, 2014 Bob, I have just checked the ORS web site and J Type speedo drive gears are available in 5,6 and 8 starts for £25. It is a long time ago, but it was fairly straight forward to change and ORS were very helpful with advice. My car is a side screen as well and it all works well with an angle drive. Quote Link to post Share on other sites
Lebro Posted August 29, 2014 Report Share Posted August 29, 2014 OK, mine is an "A" type overdrive - The parts book for the "A" type does not show the drive gear as a separate part. We don't yet know which type Ron has, but if it is "J" type then changing this gear is an option. It may depend on whether the O/D works or not, i.e. does it need to be stripped anyway. Mine did not work - it had been sitting in my neighbours shed for 20 years ! I tested it off the car using an SDS drill (hammer switched off) to turn the gearbox I/P shaft. all the gears were there, but OD did not engauge when the solenoid pulled in. I do not use an angle drive by the way. Bob. Quote Link to post Share on other sites
Willie Felger Posted August 30, 2014 Report Share Posted August 30, 2014 Ron, Where are you located. I have fitted J-type boxes to two cars (TR3A and TR6) and it is simply done. I have posted my experiences on the forum as well. Willie Felger Quote Link to post Share on other sites
Lebro Posted August 30, 2014 Report Share Posted August 30, 2014 We still don't know if it is "A" or "J" type. Quote Link to post Share on other sites
Willie Felger Posted August 30, 2014 Report Share Posted August 30, 2014 Hi again Ron, Assuming the box is out of the car - there should be a makers plate riveted to the overdrive unit. Apart from saying Laycock de Normanville, it should say J-type followed by a number. The first part will be 23/25/or/28, which is the percentage gear benefit over normal top gear. The sure fire identifier is the "solenoid", which is horizontal on the J-type. As your box is out of a 2.5 Pi - same as mine in the TR3A - it will be a J. It is an excellent box with a super overdrive. All you need is a 2.5 PI friction plate, a conversion bracket from Moss and the J type flange re-drilled to fit the prop shaft. I took the top off to check the gear teeth and changed the oil - that is all. I have a Healey 3000 gear knob with the switch on it - from Dennis Welch Motorsport for £30-ish, but you could use any switch you like. Good luck, it is an easy and very successful mod. Willie Quote Link to post Share on other sites
Lebro Posted August 30, 2014 Report Share Posted August 30, 2014 2.5 box will be expecting a diaphram clutch - not a TR4 type - release hardware is different. Solution is either transfer the TR release parts to the 2.5 box, & keep TR clutch pressure plate, or keep the 2.5 release parts, & fit a diaphram pressure plate (2.5, GT6 etc) or possibly (out of my personal knowledge zone here) a TR6 one ? Bob. Quote Link to post Share on other sites
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