mpbarrett Posted September 26, 2018 Report Share Posted September 26, 2018 I have newly rebuilt 3 rail J type od gearbox in my Herald. Its only done about 1200 miles. I have a strange problem with it. Sometimes I cant get reverse to work. It feels if the selector has moved in the correct position but there is no reverse drive. Moving the car forwards (1-4 gear) doesn't help, sometimes pushing the lever fast into reverse fixes it but not always. It seems to happen completely randomly, whether the gearbox is cold or hot. Everything else on the gearbox is excellent very good syncro and very good OD (no slipping and comes in and out nicely). I haven't had a conversation with the gearbox builder yet, just wanted to get any ideas what the problem can be? I have taken the remote gear lever off and its all seems fine, I can pull out the next layer with the selectors and have a look. I did wonder if there is a tooth missing from the reverse gear wheel and that it gets into a position where it doesn't engage? Anyway any ideas very welcome. Maybe I should book a place on the gearbox twiddle day! cheers mike Link to comment Share on other sites More sharing options...
68vitesse Posted September 26, 2018 Report Share Posted September 26, 2018 Reverse gears are straight cut, sometimes on my Vitesse, three rail J type overdrive, it will not go into reverse but letting the clutch up then trying again solves the problem by moving the gears. Not the bolt in the bottom of the gear lever fouling the extension, been there done that. Regards Paul Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 26, 2018 Report Share Posted September 26, 2018 this sounds like the reverse detent stop is not set correctly its a short setscrew stop bolt that should contact and control the reverse gate selection theres a basic setting in the workshop manual, allows the stick to shift to the left of 1st /2nd and if set too long you wont get in reverse Pete Link to comment Share on other sites More sharing options...
Nick Jones Posted September 26, 2018 Report Share Posted September 26, 2018 Sounds like engagement is marginal even when it does engage. Possibly Pete's reverse detent stop (can't picture it, been >25 years since I had a single rail box apart). Either that or something simple but hard to spot with the external linkage that is restricting movement. Don't think the missing tooth scenario works - you'd need to be missing more than one tooth to get zero drive and you'd definitely hear that on the occasions you do get drive. Nick Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 26, 2018 Report Share Posted September 26, 2018 Digging deeper theres always a chance the selector shaft interlocks balls and small rods have been mis assembled and you are trying to get 1st and reverse at the same time ...was the top cover with its forks stripped down ??? Pete Link to comment Share on other sites More sharing options...
thescrapman Posted September 27, 2018 Report Share Posted September 27, 2018 Wrong top cover? who rebuilt the box? Link to comment Share on other sites More sharing options...
mpbarrett Posted September 29, 2018 Author Report Share Posted September 29, 2018 Thanks for all the replies. Paul: tried lifting the clutch and doesn't help Pete: Do you mean the reverse detent stop that stops you outing it into reverse unless you press the lever down? or is there another adjustment somewhere? yes top cover stripped and rebuilt. I think new spring and balls were used for the detent. Have had the top cover off and it seems to be moving into the correct position and pushing the revers selector fully forward. Nick: yes the missing gear teeth was a wild idea I had while doing something else! TheScrapman: don't want to say until I have spoken to him, but you can probably guess as I am in Cambridge and you are in Suffolk... cheers mike Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 29, 2018 Report Share Posted September 29, 2018 yes the plate that blocks till push down the stop on the stick that rubs against it is adjustable when stick is in 1st 2nd side of the gate H it has a gap of 0.010-0.050" between stop bolt and plate if you can engage reverse ok by pushing the selector fork (with the top off) then the remote is the culprit you can test the 3 rail interlockers , with top cover off select to move a fork then try to move the other fork it should lock if it allows both forks to move then the interlockers are missing a trick Pete Link to comment Share on other sites More sharing options...
mpbarrett Posted October 1, 2018 Author Report Share Posted October 1, 2018 Pete how do the interlockers work? Its sort of developed with it getting worse, failing to engage reverse more often, and now when I try to move the lever into 1-2 or 3-4 it wont move into any gear and feels like it jammed. I have not yet been able to get hold of the gearbox guy... mike Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 1, 2018 Report Share Posted October 1, 2018 The rails have a groove in near there end, in the top cover there is a cross drilling which takes a pair of balls between each shaft They will only allow a shaft to slide if a ball sits in the other shafts relief, to co join the outer rails balls with the centre one there is a hole drilled through the rail so the balls sitting in the groove shunt the small rod across to also lock the balls in the other rail How do you explain this in anything understandable !!!!! Can you engage reverse with the top cover off by shifting the forks , its not unkown for the relay lever thats pivoted on the side of the box to become bent To fit /remove the top cover engage 1st gear If you can engage reverse, then try 3rd if it moves intomgeat the interlock has a problem Takes a firm effort with a pry /bar and maybe a mallet Pete Link to comment Share on other sites More sharing options...
mpbarrett Posted October 11, 2018 Author Report Share Posted October 11, 2018 quick update on this... so I don't know how I managed to jam it but I have freed it and it hasn't happened again. I have taken the top cover off and I think the problem might be a combination of play on the reverse operating lever pin and the reverse gear and the pin and the reverse selector. There seem to be a lot of free play when you move the lever. I want to take the reverse operating lever out but cant quite see how its held in. It seems to have a threaded hole in it and fitted onto the threaded section of the fulcrum pin. Can you remove it without taken any gears or shafts out of the gearbox? Maybe I should wait until after Sunday when I am going to the TSSC gearbox tutorial before I break something! I think its time to understand how the gearbox is put together. I plan to buy a cheap 3 rail one off Ebay so I can have a play at stripping and rebuilding them... Although there does seem to be a lot of parts no longer available.... Mike Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 11, 2018 Report Share Posted October 11, 2018 the lever inside the box sits on a threaded stud, think you can only remove it when the case is stripped out these levers have been known to get bent ( ive never found a bent one ,) pete have fun on gearbox day , i cant make it but im sure Henry will make it entertaining Link to comment Share on other sites More sharing options...
Nick Jones Posted October 11, 2018 Report Share Posted October 11, 2018 3 hours ago, mpbarrett said: I want to take the reverse operating lever out but cant quite see how its held in. It seems to have a threaded hole in it and fitted onto the threaded section of the fulcrum pin. Can you remove it without taken any gears or shafts out of the gearbox? Reverse operating lever pivots on the thread of that stud, or fulcrum pin as you call it. No, you can't get it in/out with the box assembled...... and I really tried. Snapped the fulcrum bolt doing an autotest....... no reverse and some slightly threatening noises caused by the lever rubbing on stuff........ Cheap easy fix, except you have remove and substantially dismantle the gearbox to get the new one in. Having not long pulled the gearbox and rebuilt it following a previous autotest I really didn't want to repeat the exercise but, in the end, repeat it I did. I don't see how it's the root of your problem though? Nick Link to comment Share on other sites More sharing options...
mpbarrett Posted October 11, 2018 Author Report Share Posted October 11, 2018 Nick and Peter Thanks for the comments my theory (well todays..) is that there is so much play that the idler gear does not always move enough to engage when you select reverse. When it has failed to engage a couple of times I have moved it fast and hard into reverse and its engaged. So I have tried to take some pictures of it, here is a short video zoomed in on the pin of the reverse operating lever and idler gear. You can see that its only just engaged in the groove in the gear and there is a lot of play of the reverse operating lever on the fulcrum bolt. Could this be the cause? I don't know but I cant see any other issues. I am trying to avoid removing the gearbox but from you have said I cant get the lever out without stripping the gearbox.... I suppose I could bend the lever by clamping a spacer between the arm and the gearbox body and then levering the bottom part to bend it towards the slot in the reverse idler gear to take up the wear between the fulcrum bolt and operating lever. Alternatively I could cut the fulcrum bolt and remove the lever, bend it to get a better fit and then turn a new pin that screws in the outside of the box.. But that means changing how Triumph engineered it, they method of have the pivoting on the thread of the fulcrum stops the operating lever falling off! mike 00002.mpg Link to comment Share on other sites More sharing options...
Nick Jones Posted October 12, 2018 Report Share Posted October 12, 2018 Can't make the video work...... may be an iPad thing..... will try PC later. If you just wanted to move the lever along the fulcrum pin then you could probably undo the nut on the outside, give the end of the stud a tap to release it from the taper splines and twiddle it to screw the lever inwards or outwards. Not sure this helps the problem though? Have you been able to speak to the box builder about it yet? Nick Link to comment Share on other sites More sharing options...
NonMember Posted October 12, 2018 Report Share Posted October 12, 2018 That really doesn't look properly engaged at all. You need to reduce the play somehow. Link to comment Share on other sites More sharing options...
mpbarrett Posted October 12, 2018 Author Report Share Posted October 12, 2018 1 hour ago, Nick Jones said: Can't make the video work...... may be an iPad thing..... will try PC later. If you just wanted to move the lever along the fulcrum pin then you could probably undo the nut on the outside, give the end of the stud a tap to release it from the taper splines and twiddle it to screw the lever inwards or outwards. Not sure this helps the problem though? Have you been able to speak to the box builder about it yet? Nick Nick here are a couple of images from the video showing the pin and reverse idler gear. Between the first and second I have moved the lever on the fulcrum pin. No I haven't managed to talk to the builder..... mike Link to comment Share on other sites More sharing options...
Nick Jones Posted October 12, 2018 Report Share Posted October 12, 2018 Looks better in the second....... could maybe even stand to come over a bit more? Does it make any difference to the original problem though? Funny thing.... the PC will play your clip, but sound only - no pictures..... Useless..... Nick Link to comment Share on other sites More sharing options...
Nick Jones Posted October 12, 2018 Report Share Posted October 12, 2018 Some relevant pics on page 10 of this thread http://forum.triumphdolomite.co.uk/viewtopic.php?f=19&t=32879&sid=0d429752fb4dd16ae33d3a6e9c2eb822&start=135 ...... which appear to show that at least some boxes have a different arrangement for the reverse gear fulcrum pin......? It is an 1850 box, but they are pretty similar apart from gear ratios..... Nick Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 12, 2018 Report Share Posted October 12, 2018 There is certainly insufficient engagement of the lever pin in the pinion Incorrectly set on its pivot or ...its got bent Pete Link to comment Share on other sites More sharing options...
mpbarrett Posted October 12, 2018 Author Report Share Posted October 12, 2018 26 minutes ago, Nick Jones said: Looks better in the second....... could maybe even stand to come over a bit more? Does it make any difference to the original problem though? Funny thing.... the PC will play your clip, but sound only - no pictures..... Useless..... Nick Nick I don't know if it will make any difference but its the only thing that I have found that doesn't look right! Before I try to bend or modify bits I am going to put the top cover back on and try to measure how far the reverse idler gear moves with the reverse operating lever in different positions and then see if I can duplicate what happens when I cant get reverse... Got to sort out a leak from our shower drain before I can play again, I should have known that boxing in all the pipework was a bad idea... BTW the images show how far the pin can move due to the play on the fulcrum bolt. Sorry about the videos, when I was working and doing technical presentations with embedded videos I learnt (the hard way) that you had to test them on the exact equipment that was being used for the presentation. The whole company had standardised Dell PC's with a standard set of software but even then one PC would play a video and the next would not! Complete nightmare. cheers mike Link to comment Share on other sites More sharing options...
Nick Jones Posted October 12, 2018 Report Share Posted October 12, 2018 45 minutes ago, mpbarrett said: when I was working and doing technical presentations with embedded videos I learnt (the hard way) that you had to test them on the exact equipment that was being used for the presentation I have that T-shirt too! It does seem to happen less these days though. Nick Link to comment Share on other sites More sharing options...
NonMember Posted October 12, 2018 Report Share Posted October 12, 2018 2 hours ago, Nick Jones said: Some relevant pics on page 10 of this thread http://forum.triumphdolomite.co.uk/viewtopic.php?f=19&t=32879&sid=0d429752fb4dd16ae33d3a6e9c2eb822&start=135 ...... which appear to show that at least some boxes have a different arrangement for the reverse gear fulcrum pin......? That's a single rail box so it will have some differences. I'm not sure how much is compatible - the gear sets are to an extent but not much of the selector mechanism. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 12, 2018 Report Share Posted October 12, 2018 The boss on the lever must almost fully engage with the pinion with just some minimal clearance to the base of the groove Moving the whole lever across to match with the gear may now make the top, cover ward not want to engage with the top of the lever This all needs some careful pros and cons of just which is the culprit Has it just been screwed too far on to the pivot thread or the lever has been distorted ??? Pete Link to comment Share on other sites More sharing options...
Nick Jones Posted October 12, 2018 Report Share Posted October 12, 2018 1 hour ago, NonMember said: That's a single rail box so it will have some differences. I'm not sure how much is compatible - the gear sets are to an extent but not much of the selector mechanism. Huh.... and there was I thinking that Mike had a single rail matching his 1500...... (J-type helping cement that impression). Always read the OP properly...... Nick Link to comment Share on other sites More sharing options...
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