jake_a Posted September 12, 2007 Report Share Posted September 12, 2007 (edited) My TR6 has developed a regular habit of locking the gearstick and selector rods so only 1st and 2nd are selectable. I know what causes this, but not why...... Basically inside the gearbox (on the nearside side of the box) there is a lever. This lever is the reverse gear selector lever. See here (item number 68 ) : http://www.rimmerbros.co.uk/tr6/images/48a.gif It is controlled by a corresponding fork on one of the selector rods (it is more of a "cup" than a fork, and is supposed to hold the small rod that sticks out of the reverse selector lever). See here (item number 99): http://www.rimmerbros.co.uk/tr6/images/44a.gif Whats happens is that when I select reverse the reverse lever pops out of the little reverse selector fork "cup". When this happens it has the effect of stopping you selecting 3rd, 4th, and reverse because the fork is wedged against the lever, only the 1st and 2nd gear are selectable as that selector rod is still free to move. I'm going to Ireland in the TR in 12 days and can't risk it happening as it a seats/carpets/gearbox tunnel out job to fix it. I **think** the problem lies in the fact that there seems to be a lot of side to side play (i.e. the rod is still firmly in place but will rotate a good few degrees) in the reverse selector shaft (item number 93). There is actually a gap of about 3mm between this shaft and the middle one where they come together to form the selector part of the shafts (i.e. where the gearstick ball sits), whereas the 1st and 2nd gear selector shaft (on the other side) sits flush against the middle shaft, thereby not allowing any side to side rotation of the shaft and its selector forks. How on earth can I fix this??!!! And is it easy to replace the reverse selector fork as it the cup part of it has started to wear at the edges, thereby making it even more likely that the lever will pop out of the cup and lock the selector rods again! Jake Edited September 12, 2007 by jake_a Quote Link to post Share on other sites
Rhodri Posted September 12, 2007 Report Share Posted September 12, 2007 Jake- My brain is numb trying to understand what's what, but the lever 68 is screwed onto the stud 69, however I cannot remember if 69 is threaded through the casing or just pushed in. If 68 is unscrewed a turn or two it will push the lever towards the centre of the box engaging it the cup some more. I adjusted mine as I rebuilt my box and seem to recall that it had to be done before the layshaft etc were put into the box rather than being able to push 69 further into the casing from outside. I can not quite follow what you mean about the selector shafts, but obviously excess wear will cause problems and may be the reason 68 is coming out of the cup, rather than it being adjusted improperly? We have several gearbox experts on here who will be able to help I'm sure! Quote Link to post Share on other sites
Richard Crawley Posted September 12, 2007 Report Share Posted September 12, 2007 Oh my god! Quote Link to post Share on other sites
jake_a Posted September 12, 2007 Author Report Share Posted September 12, 2007 Oh my god! What? The problem or my long posting?! Quote Link to post Share on other sites
rpurchon Posted September 12, 2007 Report Share Posted September 12, 2007 i have some spare top covers.complete with slector forks etc if you want to try one. £20 . is the lever that swings the reverse gear in and out bent . richard Quote Link to post Share on other sites
TIMS Posted September 13, 2007 Report Share Posted September 13, 2007 Jake This one I understand. Some careful previous owner has been a bit heavy handed in engaging reverse gear. The casting which is pinned onto the end of the reverse selector rod and accepts the bottom of the gear lever, can, and does, get bent out of shape. This causes it to no longer ride parallel to the 3rd/4th gear casting (the centre one) and can allow the casting and hence (cos it's on the other end of the same shaft) the reverse gear selector "fork" to move as you describe. If you are lucky it is just the casting but the selector rod may also be bent. It is possible, just, if you remove the gear lever, to extract the pin that holds the casting in place and replace it with another. But, as to do this you will have had to take the gearbox tunnel out, you might as well remove the top cover and take the rods out and check them all for straightness. I had to go through three 2nd hand reverse selector castings to find a good one. If you PM me I will send you the Buckeye technical piece on refurbishing the gearbox top, or perhaps somebody who knows how will provide you the link. Regards Tim Quote Link to post Share on other sites
Jersey Royal Posted September 13, 2007 Report Share Posted September 13, 2007 Jake somebody who knows how will provide you the link. Regards Tim http://web.archive.org/web/20040403214313/...x_technical.htm Quote Link to post Share on other sites
TIMS Posted September 13, 2007 Report Share Posted September 13, 2007 Guy Thanks Tim Quote Link to post Share on other sites
jake_a Posted September 17, 2007 Author Report Share Posted September 17, 2007 Jake This one I understand. Some careful previous owner has been a bit heavy handed in engaging reverse gear. The casting which is pinned onto the end of the reverse selector rod and accepts the bottom of the gear lever, can, and does, get bent out of shape. This causes it to no longer ride parallel to the 3rd/4th gear casting (the centre one) and can allow the casting and hence (cos it's on the other end of the same shaft) the reverse gear selector "fork" to move as you describe. If you are lucky it is just the casting but the selector rod may also be bent. It is possible, just, if you remove the gear lever, to extract the pin that holds the casting in place and replace it with another. But, as to do this you will have had to take the gearbox tunnel out, you might as well remove the top cover and take the rods out and check them all for straightness. I had to go through three 2nd hand reverse selector castings to find a good one. If you PM me I will send you the Buckeye technical piece on refurbishing the gearbox top, or perhaps somebody who knows how will provide you the link. Regards Tim Tim, Nail on the head! I think you have explained the problem, and cause, perfectly. I have sourced a 2nd hand dolomite sprint top cover which I believe **may** be a possible direct replacement for the one currently fitted. If not I'm guessing that I can extract the reverse selector rod from this and fit it to mine? Jake Quote Link to post Share on other sites
TIMS Posted September 17, 2007 Report Share Posted September 17, 2007 Jake Be wary about using the whole rod as they are all different with different cut-outs and indentations for different sites of the switches on the cover. If you can get away with it, just change over the casting on the gear lever end of the rod. They do seem to be common. Oh, and one other. Some of the earlier reverse castings have a right angled step up which the lever has to pass over, at present I have to lift my lever to select reverse, others seem to have a chamfer on the step, so that all that is needed is a sharp slap on the lever to get it into the reverse plane. You may wish to releve the step. (that sounds complex, just look at the castings side by side, the step is to stop accidental selection of the reverse plane) Regards Tim Quote Link to post Share on other sites
stuart Posted September 17, 2007 Report Share Posted September 17, 2007 Its best to keep the step if at all possible especially for enthusiastic gear changing!! Stuart. Quote Link to post Share on other sites
JohnC Posted September 18, 2007 Report Share Posted September 18, 2007 (edited) I think some of the archived gearbox articles by Nelson Riedel are missing photos. A while ago I pieced together complete pdf versions, which you can find here. Cheers, John Edited September 18, 2007 by JohnC Quote Link to post Share on other sites
jake_a Posted September 18, 2007 Author Report Share Posted September 18, 2007 Tim (and all who have helped!), I'm currently looking at doing a direct swap for the Dolomite unit (time is short, I sail a week today!). They do seem to be identical apart from the fact that the Dolomite it came from obviously wasn't overdrive as there is no hole for the inhibitor switch. Rimmers say this is easily corrected; "Conversion of non-overdrive top covers to overdrive type is a matter of drilling and tapping to accept a switch(es) in the correct position(s). This can be done by the owner, or by a machine shop - thread size is M16." Is this right? M16 is metric right?! Will this be an exact fit for my original lucas switches? Jake Quote Link to post Share on other sites
rpurchon Posted September 18, 2007 Report Share Posted September 18, 2007 i posted earlier i have some top covers from j type boxs with switches fitted. richard Quote Link to post Share on other sites
jake_a Posted September 18, 2007 Author Report Share Posted September 18, 2007 i posted earlier i have some top covers from j type boxs with switches fitted. richard Sorry Richard, missed that somehow. You must have thought I was very rude! Cheers for the offer, but I had to start putting the car together tonight to stand a chance of being done in time to sail next Monday. Jigsaw Racing (Triumph specialists near Kettering) managed to have my Dolomite top cover machined to accept the overdrive inhibitor switch within 4 hours of me dropping it off with no notice! Only cost £25. Fitted it before tea and have just been for a test run with the gearbox tunnel off and all seems 'A ok'. Quote Link to post Share on other sites
rpurchon Posted September 18, 2007 Report Share Posted September 18, 2007 no problem, glad its sorted richard Quote Link to post Share on other sites
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