jf1500 Posted October 11, 2022 Report Share Posted October 11, 2022 In neutral gearbox input shaft turns freely but the overdrive output turns with it. Restrain the output and I can only just turn the input by slipping the clutch plate on it. Any ideas what could be causing this? Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 11, 2022 Report Share Posted October 11, 2022 you may have a baulk ring stuck on whip the top cover off and check all synchro rings are a rattling good fit ,not gripped on the gears cone have you stripped the assy out at all ??? there is a good amount of drag from the OD planet gearing Pete Link to comment Share on other sites More sharing options...
johny Posted October 11, 2022 Report Share Posted October 11, 2022 I think theres three possibilities: The bearing between the input and mainshaft is partially seized and transmitting drive from one to the other. One of the gears on the mainshaft is partially seized to it so is transmitting drive via the laygear. A synchro ring is sticking to a cone so instead of releasing in neutral as it should it continues to transmit drive. Has the box been left a long time unused? At the very least I think you need to look inside and by rotating the input you should see where the problem lies. Then it could be worth filling with oil so everything is submerged and leaving for a few days to see if it frees off. However maybe its corrosion thats causing this in which case a strip of the internals is likely to be needed.... Link to comment Share on other sites More sharing options...
jf1500 Posted October 12, 2022 Author Report Share Posted October 12, 2022 Thanks for your replies, gives me good indication where to start looking. Box hasn't been used for +20 years so will take top off as soon as I can get the box out (short of garage space) and run through your suggestions. Will let you know what I find. Link to comment Share on other sites More sharing options...
thescrapman Posted October 13, 2022 Report Share Posted October 13, 2022 If gearbox is in car, why just try driving it? Link to comment Share on other sites More sharing options...
jf1500 Posted December 2, 2022 Author Report Share Posted December 2, 2022 At last able to get into garage and take top off gearbox. Nothing obvious at first inspection. Removed overdrive and established problem not in overdrive. Closer inspection showed 4th gear synchro ring not free like others. Gentle levering managed to move synchro hub to permit careful work with small screwdriver and synchro ring popped free of synchro hub. Now rattles like the others and shafts move freely. Plan to replace top and gear change to see if it remains free after operating gearchange a few times. Hope it was just caused by not being used for about 25 years. 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted December 3, 2022 Report Share Posted December 3, 2022 stuck baulk rings are common if selection is made with no rotation at work pleased its an easy fix ...but quite common on boxes of this era Pete Link to comment Share on other sites More sharing options...
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