TR4A1965 Posted January 6, 2019 Report Share Posted January 6, 2019 I thought I would moppet a question out there before I do more digging in case it is anything obvious that springs to your collective minds. My gearbox quite suddenly decided that going ion to 2nd gear was a problem. I was driving along and went to change down and could not get it in to 2nd without a crunch. 1st, 3rd & 4th gears seem a lot better. Maybe 3rd has a little trouble engaging. 2nd is a 'I don't want to go in'. Recent history of the box is as follows. 1: Overdrive and gearbox rebuilt by Mike Papworth 3,000 miles ago. 2: Had an overdrive issue that was the pressure relief valve - sorted no problems. 3: Complete oil change at 3,000 miles. 3: Had a grumbling clutch release bearing and replaced that all fine The overdrive is working fine. Clutch slave adjust as much as possible at the rod. Any thoughts? Best Paul Quote Link to post Share on other sites
Hamish Posted January 6, 2019 Report Share Posted January 6, 2019 3000 miles isn’t a lot. Call the gearbox builder and ask his advice especially if the oil levels are right. H Quote Link to post Share on other sites
RogerH Posted January 6, 2019 Report Share Posted January 6, 2019 Hi Paul, quite suddenly could well be the taper pin on the cross shaft. When you refitted the GB 3000 miles ago did you fit an extra pin in the cross shaft? Roger Quote Link to post Share on other sites
TR4A1965 Posted January 6, 2019 Author Report Share Posted January 6, 2019 Hi Roger, I don't think an 'extra' taper pin was fitted? What is this? Best. Paul. Quote Link to post Share on other sites
ctc77965o Posted January 6, 2019 Report Share Posted January 6, 2019 can you select reverse without a crunch? if not then that points to clutch disengagement being the issue Quote Link to post Share on other sites
RogerH Posted January 6, 2019 Report Share Posted January 6, 2019 Hi Paul, the normal taper pin can last anything from a dozen miles to 50,000 miles. Breaking at 3000 miles is not unknown. To determine positively if it is the pin you really need to pull the GB out. However if you get under the car position the actuating lever for the clutch fork cross shaft and push it fully rearwards. It should be vertical as near as damn it. Another dodgy test - pull the lever fully forwards, then gently push it rearwards. When the lever gets near vertical continue to push gently and feel for any gentle changes in feel. This could indicate the broken taper pin snagging over a rough sheared face. - may be. Roger Quote Link to post Share on other sites
Lebro Posted January 6, 2019 Report Share Posted January 6, 2019 Surely if the clutch was the problem then any gear would be hard to engage ? Bob. Quote Link to post Share on other sites
TR4A1965 Posted January 6, 2019 Author Report Share Posted January 6, 2019 All gears are stiffer than usual. Reverse is fine but stiffer than usual. Roger I have an awful feeling that you maybe right!!! Gearbox out again!!!!! Arrrrgghhhh!!!!! Where can one purchase an industrial strength taper pin??? The best. Best. Paul. Quote Link to post Share on other sites
RogerH Posted January 7, 2019 Report Share Posted January 7, 2019 Hi Paul, there are no ideal taper pins. The pin is not the problem but the quality of the taper hole. Any slight slack in the hole converts the shear force into tensile force. The pin is happy with the shear. The standard fix is to fit the taper pin (I get mine form the TRShop) AND either a roll pin (preferred) or bolt 3/16"diameter at 90' to the taper. Roger Quote Link to post Share on other sites
AndrewMAshton Posted January 7, 2019 Report Share Posted January 7, 2019 Or, even better, as a belated Christmas present to self, buy and fit the fully hydraulic co-axial clutch supplied by the suppliers of the racing upgrades, much lighter clutch and gets rid of all the faults of the original, cheers, Andrew Quote Link to post Share on other sites
Hamish Posted January 7, 2019 Report Share Posted January 7, 2019 This is mine. Done as part of my gearbox upgrade. Quote Link to post Share on other sites
Tonyloz Posted January 7, 2019 Report Share Posted January 7, 2019 +1 for the extra shaft pin I use a stainless bolt with nyloc nut on all my rebuilds....cheap and effective Your problem sounds like a defective pin Quote Link to post Share on other sites
Drewmotty Posted January 7, 2019 Report Share Posted January 7, 2019 Revington supply a tougher taper pin but I still fit a roll pin to help it out. Wider shaft bushes also help and you might as well fit them too while the gearbox is out on the bench Quote Link to post Share on other sites
TR4A1965 Posted January 7, 2019 Author Report Share Posted January 7, 2019 Cheers chaps. Investigation starts tomorrow. Best. Paul. Quote Link to post Share on other sites
Drewmotty Posted January 7, 2019 Report Share Posted January 7, 2019 Take a look here Paul: https://www.tr-register.co.uk/group/devon/social-report/2018/03/1000/In-the-Garage-Easter-2018 Clutch actuating lever mods are covered a little bit down the first page. Quote Link to post Share on other sites
rcreweread Posted January 7, 2019 Report Share Posted January 7, 2019 Paul I hope you find not too much wrong with your box and it's a simple repair. However, if you fancied having an uprated box and 25% ratio OD, I have a spare gearbox and OD just fully rebuilt by Pete Cox, which has been uprated with the strengthened laygear and additional bearing, an extra pinned crosshaft, a 25% ratio J type OD, modified to work in 2nd gear if wanted, complete with an A type to J type mounting kit - this could be available to purchase outright at a very reasonable cost. If you want the ultimate package, Pete is in the process of putting together various bits I've collected into a fully TR converted Stag box with a 28% ratio overdrive, which I may be persuaded to let go. PM me if this is of interest. Cheers Rich Quote Link to post Share on other sites
TR4A1965 Posted January 28, 2019 Author Report Share Posted January 28, 2019 So, We replaced the release bearing and put a new fork on. On the test drive a massive crunch in second persists. So we drained the oil and it is full of metal. This is a box that was rebuilt by Mike Papworth 4,000 miles ago???~ In any event, it looks like another rebuild is in order as we can see bits of bearing in the oil??? Bummer:-( Quote Link to post Share on other sites
RogerH Posted January 28, 2019 Report Share Posted January 28, 2019 Hi Paul, PM sent Roger Quote Link to post Share on other sites
TR4A1965 Posted March 6, 2019 Author Report Share Posted March 6, 2019 Got to the bottom of it. Front shaft bearing collapsed. Damaged front shaft and main shaft. Metal deposits throughout the box:-( Complete rebuild required! to get rid of loose metal etc. Let's hope this time we nail it for good. Quote Link to post Share on other sites
Geko Posted March 6, 2019 Report Share Posted March 6, 2019 Under warranty I reckon... Quote Link to post Share on other sites
AndyR100 Posted March 6, 2019 Report Share Posted March 6, 2019 Sorry to hear that Paul, I’d expect Mike to handle this sensibly. ....... Andy Quote Link to post Share on other sites
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