Any Laycock overdrive experts here?
Discussion
1974 Reliant Scimitar, manual gearbox with the J type overdrive. I have the gearbox on the bench and I’m stuck trying to remove the overdrive off the back of the ‘box. I’ve removed the retaining nuts and tapped the OD back about 5mm then it’s stopped. Apparently there is a cam and it has to line up to allow the OD to slip off.
Anyone any experience in removing the OD and has some tips to try?
Reason I need to remove it is to rebuild the gearbox.
Anyone any experience in removing the OD and has some tips to try?
Reason I need to remove it is to rebuild the gearbox.
Google says
"The manuals suggest the following procedure if the mainshaft is hung up: operate the solenoid, remove the plug in front of the solenoid and force oil into the chamber around the operating valve at the front of the solenoid. (The adaptor hose normally used to connect a pressure gauge can be used to connect to a grease gun filled with oil.) This should shift the unit out of direct drive thus relieving the spline loading."
"The manuals suggest the following procedure if the mainshaft is hung up: operate the solenoid, remove the plug in front of the solenoid and force oil into the chamber around the operating valve at the front of the solenoid. (The adaptor hose normally used to connect a pressure gauge can be used to connect to a grease gun filled with oil.) This should shift the unit out of direct drive thus relieving the spline loading."
Thanks gents.
I’ve got a grease fitting on order that I hope will allow me to pump oil in as described.
I’ve tried turning the input shaft and seeing if the OD comes free, but no luck yet.
I am assuming the gearbox has to be in neutral to do this too.
I’m going to try and call Overdrive Services for advice too. I missed the part in the manual about how to disengage the OD prior to removing the transmission from the car.
I’ve got a grease fitting on order that I hope will allow me to pump oil in as described.
I’ve tried turning the input shaft and seeing if the OD comes free, but no luck yet.
I am assuming the gearbox has to be in neutral to do this too.
I’m going to try and call Overdrive Services for advice too. I missed the part in the manual about how to disengage the OD prior to removing the transmission from the car.
Don't know if this is of any help:
"If you are going to remove the overdrive, it is highly recommended to drive the car and shift it into overdrive and then, with the clutch pedal depressed, disengage the overdrive. This will relieve any torque that remains, and should allow the unit to slide off the transmission output shaft easily. You can also remove the driveshaft, and accomplish the same thing. I have seen a few cases where the overdrive unit was all but impossible to remove from the transmission because of internal pressures that couldn't be released. This is much worse if the whole transmission is out of the car. It can still be a struggle to remove, in the car, if this detail is omitted. More than one promising junkyard unit has been left behind for this reason. I have heard that the unit can be disassembled in place in this case, but have never had the pleasure, myself."
https://www.ipdusa.com/techtips/10090/j-type-overd...
Been a long time since I had my SE5 but I'd suggest asking the question on a Scimitar specific forum such as: https://www.scimitarweb.co.uk/
"If you are going to remove the overdrive, it is highly recommended to drive the car and shift it into overdrive and then, with the clutch pedal depressed, disengage the overdrive. This will relieve any torque that remains, and should allow the unit to slide off the transmission output shaft easily. You can also remove the driveshaft, and accomplish the same thing. I have seen a few cases where the overdrive unit was all but impossible to remove from the transmission because of internal pressures that couldn't be released. This is much worse if the whole transmission is out of the car. It can still be a struggle to remove, in the car, if this detail is omitted. More than one promising junkyard unit has been left behind for this reason. I have heard that the unit can be disassembled in place in this case, but have never had the pleasure, myself."
https://www.ipdusa.com/techtips/10090/j-type-overd...
Been a long time since I had my SE5 but I'd suggest asking the question on a Scimitar specific forum such as: https://www.scimitarweb.co.uk/
J-type also on late TR6 too, so you could ask on the TR forums. My J-Type packed up - clutch slipping, and my father stripped it down and rebuilt it on tbe bench. I can’t remember anything about how he did it, except that it involved badly injuring his thumb, and lots of swearing (he rarely swore).
paintman said:
Don't know if this is of any help:
Similar note in the Vauxhall manual for the J-type overdrive:"If, prior to removal, the overdrive was disengaged during acceleration, the splines in the planet carrier and in the uni-directional clutch may remain torsionally loaded on the transmission mainshaft. This condition will prevent the overdrive being withdrawn from the mainshaft. Therefore, before commencing removal operations, drive the car in third or top gear, engage overdrive then disengage the overdrive with the clutch pedal depressed and leave in this condition ready for removal. "
Of course, no note about how to get around it if your engine exploded during hard acceleration with the overdrive engaged.
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