boxofbits Posted March 18, 2020 Report Share Posted March 18, 2020 Evening All While overhauling my TR4a gearbox I've noticed some brass filings residing in the lower front section of the overdrive unit. The only brass component I can see in the immediate vicinity is the brass bush which supports the mainshaft when inserted into the overdrive, but this doesn't look particularly worn. It might be that they have migrated in the oil flow from another part of the overdrive, so without stripping the unit which works really well, I wondered if anyone has seen this before and it's most likely origin? Regards Kevin Quote Link to post Share on other sites
ctc77965o Posted March 19, 2020 Report Share Posted March 19, 2020 There's GOLD in them thar overdrives! I gonna stake my claim! Quote Link to post Share on other sites
Chilliman Posted March 19, 2020 Report Share Posted March 19, 2020 That's a lot...not seen that in the overdrive before but had something similar in the box when the old style top hat bush had split in two and worn itself away.... Quote Link to post Share on other sites
boxofbits Posted March 19, 2020 Author Report Share Posted March 19, 2020 2 hours ago, Chilliman said: That's a lot...not seen that in the overdrive before but had something similar in the box when the old style top hat bush had split in two and worn itself away.... Hi John Funnily enough I did change the top hat bush, but not because it was worn. I changed it for a steel bush with a slightly wider thrust washer by about 0.005". The bush itself is in remarkable condition, and I cannot see any scuffing on the overdrive shaft bush. Unless its remnants from a previous repair, but would think they would've flushed it through? Kevin Quote Link to post Share on other sites
jerrytr5 Posted March 19, 2020 Report Share Posted March 19, 2020 Syncro cones? Jerry Quote Link to post Share on other sites
Chilliman Posted March 19, 2020 Report Share Posted March 19, 2020 I agree - you'd certainly like to think it is not the remnants of a previous repair, I would think the next most likely candidate in the overdrive unit would be the thrust washer at the base of the uni directional clutch which can break up...? Quote Link to post Share on other sites
Tim Carr Posted March 19, 2020 Report Share Posted March 19, 2020 My thoughts would be item 104 in the overdrive section of the Moss parts book. If these are slightly too large the planet gears happily machine them to size leaving traces of brass. It should be the right size now. Quote Link to post Share on other sites
boxofbits Posted March 19, 2020 Author Report Share Posted March 19, 2020 Hi John/Tim It looks like your diagnosis might be correct. Tim I think you may have been referring to the TR5/6 'A' type O/D as item 104, while I've been looking at the plate for the TR4a which I would think is the same item no: 66. However, the notes do bring some TRepidation! 66 THRUST WASHER Notes: Total destruction of the thrust washer and its adjusting washers is a common occurrence, and will require skilled rectification to the casing and bushes. See less 500610 £18.00 Kevin Quote Link to post Share on other sites
boxofbits Posted March 19, 2020 Author Report Share Posted March 19, 2020 2 hours ago, jerrytr5 said: Syncro cones? Jerry Synchro's look good Jerry ( Dave thinks its gold) Kevin Quote Link to post Share on other sites
Tim Carr Posted March 19, 2020 Report Share Posted March 19, 2020 Kevin, Yes, it is item 104 in the Moss TR6 parts book and if you are lucky it will have been machined to size but if not it will be broken. My overdrive was lucky. Tim Quote Link to post Share on other sites
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