PhilipB Posted July 13, 2015 Report Share Posted July 13, 2015 Hi I have a TR2 with an uprated all synchro gearbox with uprated overdrive currently running 20w/50 oil. That was changed last spring since when I've only done about 600 miles The box has been trouble free until this year when it has become increasingly difficult to change gear when the gearbox is hot. There are no problems when the engine and box are cold but once up to temperature it’s becoming a nuisance I’ve changed the clutch fluid (which had been overlooked) which has improved the gear change but the problem has persisted. Because it improved, it might point to clutch issues but the engagement point on the pedal travel doesn’t seem to change with temperature and there are no signs of fluid loss (hard to tell round the slave cylinder because of the ever present oil drips but the fluid level doesn’t drop). The clutch is a TR6 cover and plate on a TR4A aluminium flywheel Next thoughts are to change the oil for say Millers EP 80w90 Any ideas? Quote Link to post Share on other sites
percy2 Posted July 13, 2015 Report Share Posted July 13, 2015 Did you top up the gearbox after using overdrive? Quote Link to post Share on other sites
PhilipB Posted July 13, 2015 Author Report Share Posted July 13, 2015 Yep. (No obvious signs of leaks but haven't checked the level this year) Oil was changed early 2014 and the issue has only developed this year Quote Link to post Share on other sites
RogerH Posted July 13, 2015 Report Share Posted July 13, 2015 Hi Philip, you have tried 20w/50 and are now considering EP 80W/90. Have thought about using a gearbox oil Penrite 40 or similar. However with the heat I would have thought the problem lies in the clutch area. What are the linkages like - worn clevis pins/holes etc Roger Quote Link to post Share on other sites
Lebro Posted July 13, 2015 Report Share Posted July 13, 2015 Simple clutch test: Start engine. depress clutch. wait 30 seconds. slowly engage reverse gear. (no synchro on reverse) If it goes in without a crunch then clutch has fully released. repeat this when everything is hot (i.e. when you are having problems in other gears). Bob. Quote Link to post Share on other sites
Guest ntc Posted July 13, 2015 Report Share Posted July 13, 2015 The oil will have nowt to do with it. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 14, 2015 Report Share Posted July 14, 2015 (edited) What Roger said plus Check the clutch adjustment to eliminate it - that is if you still have the original TR2-4 system and not the TR4A onwards solid rod, no return spring, hydrostatic system at the clutch slave. Which hole is the clutch slave fork connected to on the bell housing clutch lever? Is the steady rod to the engine sump screw from the slave bracket present? My own car is prone to gear crunch if I fail to readjust the clutch correctly. Peter W Edited July 14, 2015 by BlueTR3A-5EKT Quote Link to post Share on other sites
PhilipB Posted July 14, 2015 Author Report Share Posted July 14, 2015 Thanks Bob, looks like clutch issue Fine when cold but the clutch isn't releasing when hot Likely causes? Phil Quote Link to post Share on other sites
PhilipB Posted July 14, 2015 Author Report Share Posted July 14, 2015 Thanks Roger and Peter, I'll crawl underneath tonight and have a look Phil Quote Link to post Share on other sites
PhilipB Posted July 19, 2015 Author Report Share Posted July 19, 2015 Thanks everyone Problem was clutch actuating rod needed adjusting. Everything else was fine, stay rod in place, clevis pin and (middle) hole in lever were fine. Still puzzled why it released when cold but not when hot but problem solved. Another thing to keep my eye on. Thanks for your guidance Phil Quote Link to post Share on other sites
Tim T Posted September 20, 2022 Report Share Posted September 20, 2022 Will the points/checks raised above apply to TR5 overdrive box as well? Would an oval hole in the clutch pedal also result in difficulties? Thanks, Tim Quote Link to post Share on other sites
RogerH Posted September 20, 2022 Report Share Posted September 20, 2022 Hi Tim, any slack will cause problems. You can adjust out the slack caused by oval/worm holes/pin but they will increase the load on your legs when pressing down on the pedal. Roger Quote Link to post Share on other sites
Tim T Posted September 21, 2022 Report Share Posted September 21, 2022 Thanks Roger. I will put it on my list of jobs for the winter. Cheers, Tim Quote Link to post Share on other sites
Tim T Posted September 21, 2022 Report Share Posted September 21, 2022 Roger, Do you think that fitting an adjustable pushrod on the clutch slave cylinder would be an option? Cheers Tim 18 hours ago, RogerH said: Hi Tim, any slack will cause problems. You can adjust out the slack caused by oval/worm holes/pin but they will increase the load on your legs when pressing down on the pedal. Roger Quote Link to post Share on other sites
stuart Posted September 21, 2022 Report Share Posted September 21, 2022 21 minutes ago, Tim T said: Roger, Do you think that fitting an adjustable pushrod on the clutch slave cylinder would be an option? Cheers Tim You shouldnt really need it if you have taken all the slack out of the actuating mechanism, also do you have the right pushrod on the master cylinder as this has come up before with the left hand drive push rod being shorter than the right hand drive one, check your original if you have replaced it. Stuart. Quote Link to post Share on other sites
Tim T Posted September 21, 2022 Report Share Posted September 21, 2022 49 minutes ago, stuart said: You shouldnt really need it if you have taken all the slack out of the actuating mechanism, also do you have the right pushrod on the master cylinder as this has come up before with the left hand drive push rod being shorter than the right hand drive one, check your original if you have replaced it. Stuart. The master cylinder and rod are the original ones reconditioned by Past Parts. Will have good look through the whole linkage and have a fiddle ….. Thanks, Tim Quote Link to post Share on other sites
Nobbysr Posted September 26, 2022 Report Share Posted September 26, 2022 if you have doubts on the operating temperature you use these https://www.testo.com/en-UK/products/temperature-measuring-strips i have used them during engine trials and they are good for an indicative reading , as long as the surface is clean they stick ok , i normally use brake cleaner on the surface and we have been able to detect bearing issues without the use of an infrared spot temperature device .. i'm sure someone must have used them before but just in case Im putting together a gear oil comparison document which is a quick comparison of the physical properties of each make, viscosity and type of gear oil and engine oils so if anyone has product suggestion, i can see if i can locate the technical data and then share the document i have some data from my time in Castrol & BP but its been a few years since my automotive days so just let me know the product name and ill see what vi can do . It will then be possible to compare viscosity of multigrade gear oil v Mono v Engine oils mono and multigrade cheers Steve Quote Link to post Share on other sites
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