CtrMint Posted December 3, 2021 Share Posted December 3, 2021 Hey All,, I've been doing plenty of background reading regarding a gearbox oil change on my 420R. There isn't a huge amount of info out there. I have however come across information on old forum posts inc Pistonheads which says the Mazda 5 speed doesn't have a drain plug, and also there's a bolt near the fill plug which must not be removed, and if removed the box needs a rebuild as it holds some internal parts. eek!Given the uncertainty and since the box doesn't really need an oil change, I'm starting to become slightly less enthusiast. I'm simply trying to be super proactive changing every serviceable item while undertaking my diff project. But as they say, 'if it aint broke', and knowing my luck I'll create a new problem for myself!If any of the regular experts could offer advice I'd appreciate it. I thought it would be as simple as drop oil via an obvious drain plug, then refill same amount, via obvious fill plug. The only challenge being the fill plug access, but that's usual Caterham life.thanks in advanceCheersMark Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted December 3, 2021 Member Share Posted December 3, 2021 While we're waiting for confirmation about there being a drain plug or not...... on most gearboxes you can remove the oil with a pump and a flexible pipe from above. Several recommendations in the archives. And much easier if the oil is warm.Jonathan Link to comment Share on other sites More sharing options...
ChrisC Posted December 3, 2021 Share Posted December 3, 2021 Don't forget it may be a Mazda gearbox but it's in a Caterham casing. The conversation is done by that company I provided the link to the other day. Given the lack of information I would start there. Link to comment Share on other sites More sharing options...
AG2728 Posted December 3, 2021 Share Posted December 3, 2021 My 420 with the Mazda 5 speed certainly has a drain plug as normal.Also, you cant really go wrong when filling it, as there is an access hole with a grommet in the offside of the transmission tunnel and when you remove that, the fill plug is right behind it.Andy Link to comment Share on other sites More sharing options...
K7 VCT Posted December 3, 2021 Share Posted December 3, 2021 Mazda 5 speed is all mazda....???? With caterham bell housing 6 speed is caterham own Link to comment Share on other sites More sharing options...
Wrightpayne Posted December 3, 2021 Share Posted December 3, 2021 I've been into Vitesse when they happened to be building mazda boxes for caterham. I can confirm they have a caterham specific mid case and bellhousing. The replacement bellhousing is to adjust the angle the box presents to the engine as the engine cant is different between the MX5 and seven. Link to comment Share on other sites More sharing options...
CtrMint Posted December 4, 2021 Author Share Posted December 4, 2021 Any chance some one could confirm the drain plug, is its the really large plug face down or the smaller to the side?Thanks Link to comment Share on other sites More sharing options...
CtrMint Posted December 4, 2021 Author Share Posted December 4, 2021 I'm assuming one of these ? Link to comment Share on other sites More sharing options...
CtrMint Posted December 4, 2021 Author Share Posted December 4, 2021 im thinking its the 24mm... Link to comment Share on other sites More sharing options...
Dixa1225 Posted December 4, 2021 Share Posted December 4, 2021 Yes the large 24mm underneath the box . Link to comment Share on other sites More sharing options...
CtrMint Posted December 4, 2021 Author Share Posted December 4, 2021 thanks..... really appreciate the help. Link to comment Share on other sites More sharing options...
22daz Posted December 4, 2021 Share Posted December 4, 2021 Fill is the square plug on the left hand side of the gearbox. Link to comment Share on other sites More sharing options...
ChrisC Posted December 5, 2021 Share Posted December 5, 2021 This may be obvious, but might as well say it, always ensuring you can access and loosen the fill plug before the drain plug. It prevents a simple job from escalating. Link to comment Share on other sites More sharing options...
CtrMint Posted December 5, 2021 Author Share Posted December 5, 2021 Thanks all. Working out the fill wasn't too bad. It was the drain mainly.I know what you mean Chris, wouldn't have attempted if I didn't have the fill released. Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted December 5, 2021 Area Representative Share Posted December 5, 2021 Some time ago it was suggested that the 'Mazda' G Box has to be refilled from two points ? One underneath is obvious but the other was from the top of the casing ? Link to comment Share on other sites More sharing options...
Doc007 Posted December 5, 2021 Share Posted December 5, 2021 I was told there is a small amount of oil that is poured in to the top of the box via the gear lever hole. Don't know whether this is true... Link to comment Share on other sites More sharing options...
Dixa1225 Posted December 5, 2021 Share Posted December 5, 2021 Yep, oil in the gear lever turret. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted December 5, 2021 Member Share Posted December 5, 2021 It would be great if someone could summarise all of this in a Guide. As Alcester Racing Sevens did for the Ford Type 5.Jonathan Link to comment Share on other sites More sharing options...
CtrMint Posted December 5, 2021 Author Share Posted December 5, 2021 I will be writing up the process for my blog, Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted December 5, 2021 Member Share Posted December 5, 2021 Excellent.ThanksJonathan Link to comment Share on other sites More sharing options...
7 wonders of the world Posted December 5, 2021 Share Posted December 5, 2021 Mazda 5 speed needs up to 250ml in the turret accessed by removing the gearlever...Mazda 6 speed (although not used in Caterhams) does not as this area is lubricated from the gearbox Link to comment Share on other sites More sharing options...
StevehS3 Posted December 5, 2021 Share Posted December 5, 2021 Does the oil in the turret get drained through the bottom drain plug (and therefore need replacement). Link to comment Share on other sites More sharing options...
CtrMint Posted December 5, 2021 Author Share Posted December 5, 2021 I assumed it didn't, otherwise we'd be able to fill via the turret, though if I'm wrong hopefully some one will correct me. Link to comment Share on other sites More sharing options...
Bone Rat Posted December 7, 2021 Share Posted December 7, 2021 Hi, Have a mx5 (NC 3.5 to be anal) along with a 150 Seven. Yup, the 5 speed box is drained on a regular basis - recommended about every 5 years or 60k miles - most do it sooner to maintain the change. The turret is also a regular check and may need a top up as it leaks into the box over the years, can't top up a 5 spd through it. Lots of info on the plugs on line. It's another car that attracts the self maintaining. Andy Link to comment Share on other sites More sharing options...
PhilT Posted March 9 Share Posted March 9 Just a little info to add, I’ve just changed the gear oil in my 2018 420R and replaced the drain plug with a magnetic Gold Plug M18 x 1.5 number MP-10. The std plug did have a magnetic but the Gold Plug is significantly stronger. The filler plug was a little corroded so I also replaced this with a Jass Performance stainless version https://www.ebay.co.uk/itm/196026719273?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=s6LgY7zoS-W&sssrc=4429486&ssuid=7rWpRUJiSXS&var=&widget_ver=artemis&media=COPY Link to comment Share on other sites More sharing options...
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