Some overdrive maintenance is possible while the gearbox is in the car. This also is the first steps in problem resolution or diagnostics. If the problems remain then you are going to need to pull the engine and gearbox. This will enable you to get more serious about overdrive repairs and opening up the overdrive unit.
This is a series of videos from John Twist of University Motors Ltd. They show the 3 main elements of the overdrive that can be serviced with the gearbox in the car.
- Solenoid
- Oil Pressure Relief Valve
- Oil Pump
If you undertake overdrive maintenance as shown, pay incredibly close attention to the order of the various bits in disassembly and reassembly. From my experience the oil pump can be really difficult to reinstall when the gearbox is in the car. Even John notes this can be “a real bugger”. I’d say that’s an understatement. Not recommended if you have never done this before!
Step 1 – Oil Pressure Relief Valve #
Step 2 – Solenoid & Oil Pump #
John mentions black label and blue label overdrives in this video. See this article for information about the types of overdrive options used on the MGB.
Step 3 – Reassembly #
John Twist of University Motors Ltd. is a great resource and supporter of the MG community. His website has a great deal of information available for free. Also, John has created hundreds of videos shared on the University Motors channel on YouTube. some of which are embedded here. Given all the contributions John makes, please consider using the donate button on his website home page if this information has helped you. Also you can use the button provided here.
John Twist Donations via PayPal
Other Materials #
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