Z320 Posted June 29 Report Posted June 29 (edited) Good morning overdrive specialists, a friend of mine wants to buy an overdrive gearbox for his TR6 and he found an offer at "small adverts". Gearbox with J-type overdrive, but the previous owner states it slips under load when the oil is hot, and explains "perhaps only an issue of a different oil?". He himself solved the problem by installing a standard 4 speed gearbox, because "he needs no obverdrive". What could be the problem of this overdrive. Regards from Jochen O. and me Ciao, Marco Edited June 29 by Z320 Quote
Lebro Posted June 29 Report Posted June 29 Should never slip when in direct drive - the one way clutch (roller bearing type) should lock up. If it's only slipping from overdrive mode down to direct drive mode then worn friction rings could be the problem, or low oil pressure. Bob Quote
RogerH Posted June 29 Report Posted June 29 Hi Marco can you edit your title and correct the typo TYPE instead of TPYE it is drving me mad just seeing it. Thank you. Roger Quote
Z320 Posted June 29 Author Report Posted June 29 (edited) That remindes me to a history teacher of mine, more than 40 years ago. Hi stated to a school test "it is always interesting how pupils write the same words in again and again new combinations of letters" Did you know: any txet is good to raed, as lnog all leettrs are terhe AND the frsit and lsat ltteer is crorect? Edited June 29 by Z320 Quote
Z320 Posted June 29 Author Report Posted June 29 (edited) Answer is in, W90 GL4 is in the od / gb, is this the correct oil, please? Edited June 29 by Z320 Quote
Z320 Posted July 15 Author Report Posted July 15 Hi, I have news about the slipping J-overdrive. It is said it is only for a Spitfire? Are there different specifications for overdrives, please? Ciao, Marco Quote
rcreweread Posted July 15 Report Posted July 15 3 hours ago, Z320 said: Hi, I have news about the slipping J-overdrive. It is said it is only for a Spitfire? Are there different specifications for overdrives, please? Ciao, Marco Marco - are you sure its a j type? I thought Spitfires had a D type OD which is a weaker unit than a J type Cheers Rich ( in the Ardenne Forest for Spa F1 at the weekend - sunny at the moment but not so much for the weekenfd race) Quote
Z320 Posted July 15 Author Report Posted July 15 (edited) Hi Richard, I know nothing about overdrives and repeat simply what I'm told by a freind how asks for help and by the guy selling it. Gearbox and overdrive are now seperated, the overdrive sold as "J type for Spitfire 1500" Ciao, Marco Edited July 15 by Z320 Quote
rcreweread Posted July 15 Report Posted July 15 33 minutes ago, Z320 said: Hi Richard, I know nothing about overdrives and repeat simply what I'm told by a freind how asks for help and by the guy selling it. Gearbox and overdrive are now seperated, the overdrive sold as "J type for Spitfire 1500" Ciao, Marco That certainly looks like a J type - I cant quite read the serial number on the rectangular plate rivetted to the side of the sump - I have a reference document at home which should tell me exactly what this unit is, but I wont be home till the end of next week. The first two numbers in the serial number denotes the OD ratio which for TRs should be 25(%) - occasionally you might find 28(%) which will have originated in some saloons/estates. The next numbers dente the model this unit was originally supplied for and the last numbers relate the number of that unit built in that model range. I don't seem to be able to blow up the image to read the numbers clearly - maybe someone on here can Cheers Rich Quote
stuart Posted July 15 Report Posted July 15 15 minutes ago, rcreweread said: That certainly looks like a J type - I cant quite read the serial number on the rectangular plate rivetted to the side of the sump - I have a reference document at home which should tell me exactly what this unit is, but I wont be home till the end of next week. The first two numbers in the serial number denotes the OD ratio which for TRs should be 25(%) - occasionally you might find 28(%) which will have originated in some saloons/estates. The next numbers dente the model this unit was originally supplied for and the last numbers relate the number of that unit built in that model range. I don't seem to be able to blow up the image to read the numbers clearly - maybe someone on here can Cheers Rich Numbers are 25 115868 010 214 Stuart. Quote
RAHTR4 Posted July 15 Report Posted July 15 Marco, This overdrive was is listed as originally fitted to the Spitfire MK V from 1974 to 1981. Regards, Richard Quote
Z320 Posted July 15 Author Report Posted July 15 Stuart and Richard, with a great hug, thank you both very much. Ciao, Marco Quote
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