Guest ade Posted July 5, 2004 Report Share Posted July 5, 2004 Hi all The overdrive on my TR works very well when cold and for the first 30-40 mins. When the car is fully warmed/ hot the overdrive is slow to engage - It doesn't fall out though. I can hear the solenoid switching, so is it likely that some adjustment is required or is something more serious in the offing? Cheers Ade Quote Link to post Share on other sites
john minchin Posted July 5, 2004 Report Share Posted July 5, 2004 Perhaps the oil is either too thin when it gets hot or the oil level is too low. Although I fear the good old discussion on 20/50 engine oil against EP90 I use EP80 (as I got it cheaper than EP90) and it has worked just fine in my A type O/D for 10 years. It may be the pump seal which I think is in the depths of the O/D. I think EP90 will temparorily mask the fault. Quote Link to post Share on other sites
Guest ade Posted July 5, 2004 Report Share Posted July 5, 2004 it's running with Penrite's gearbox oil at present - not sure how it compares to EP90, but it's v viscous stuff. (takes AGES to fill an empty gearbox) Am I right in thinking that 2 litres of oil is correct for gearbox + overdrive. It was overflowing when I filled it, but I know it takes a while for the oil to seep throught to the o/d Ta Ade Quote Link to post Share on other sites
Guest ade Posted July 5, 2004 Report Share Posted July 5, 2004 btw, is it possible to get the o/d off with the gearbox in situ, or is it a gearbox out job?? Quote Link to post Share on other sites
Dale Moore Posted July 6, 2004 Report Share Posted July 6, 2004 Hi Ade Would agree with John that it sounds mechanical, if the solenoid is operating the same instant you select the overdrive. The overdrive pump is driven at road speed, does the overdrive shift better at high road speed or no different? If so this would indicate a worn pump. Low oil pressure generally, would indicate a broken or weak accumulator spring, this can be replaced in situ. An adaptor and gauge can be made up to check oil pressure via the operating valve plug. Speak to ORS in Sheffield, usually very helpful. The gearbox must be removed from the car for dismantling. It is possible to split the overdrive from the gearbox horizontally, but reassembly requires the springs to stand vertically (grease helps) Regards Dale Quote Link to post Share on other sites
Ade-TR4 Posted July 7, 2004 Report Share Posted July 7, 2004 hi Dale, the od works better at low/ mid range speeds (oddly) and struggles at higher speeds, often needing a couple of goes to get it to shift. Once shifted it stays in OK. I wonder if there's some muck in the oil (it's new oil but the od hasn't been used for ages and may have had a build up of crud in it?) Is Penrite's oil decent stuff? (note that I don't want to open another od oil debate!!!) Any further thoughts? Ade Quote Link to post Share on other sites
Dale Moore Posted July 7, 2004 Report Share Posted July 7, 2004 Hi Ade Try this link to view workshop manual for overdrive. http://www.jc42.dial.pipex.com/tr/model/overdrive.htm I think oil contamination is unlikley.EP oil caused the overdrive to slip in low gear in my 4a, but after changing to 40 sae motor oil Ive had no problems, and the gearbox seems ok with it. You can check the gauze filter on the overdrive, by removing the large brass plug, if you decide to drain the oil. Try running the car in gear, on axle stands ( front wheels chocked etc) with gearbox cover removed and check operation of adjustment setting lever, maybe a small adjustment is required here. Mind tie fingers or other body parts, in prop shaft, if you decide on this course of action Regards Dale Quote Link to post Share on other sites
Don Elliott Posted July 8, 2004 Report Share Posted July 8, 2004 I have an "A" type overdrive in my TR3A and when I click into overdrive, I have to let up on the petrol pedal for about half a second (when switching into O/D above 2500 RPM) to make sure it really switches into overdrive when in 2nd gear. Otherwise it will be slow to go into O/D - it seems to slip a bit. Switching into 3rd or 4th gear is never a problem. I recently checked the pressure output of my overdrive pump with a glycerine filled guage as Dale suggested three items above and it reads 325 psi. Continuing a little faster on the engine speed, the gauge chatterers or vibrates between 325 and 350 psi. Once I have switched completely into overdrive in any gear, it stays in overdrive till I click off the O/D switch. Don Elliott, 1958 TR3A Quote Link to post Share on other sites
Ade-TR4 Posted July 8, 2004 Report Share Posted July 8, 2004 sounds just like mine!! - I'm going to try and adjust the lever, otherwise it can wait 'till winter cheers again ade Quote Link to post Share on other sites
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