MGB Register Forum

I'm new to this stuff so would appreciate some advice. I want to change the gearbox and OD oil and change the OD filter. Can anyone talk me through what I need to do or point me in the direction of a YouTube video. Thanks in advance.

Hi Tim,
There are some excellent videos by John Twist of University Motors on you tube who covers this & many more aspects of looking after an MGB.
Cheers
Charles

Tim,
alternatively you could get hold of a workshop manual (Haynes or the official one - both are easily purchased). The procedures are well described in them.
The main difficulty is refilling without getting oil on your carpets. A funnel and a long piece of flexible tube come in handy, together with carefully measurement of the volume of oil you are putting in.

Ian F

Hi Tim

Your first job is to establish which type of gearbox you have. Some 1974 cars are the older type (Top fill) and some are later (side fill) You'll be able to determine this by looking down the left side of the gearbox (passenger side) if you can see a plug on the side of the gearbox, it's the later one.

The earlier 'box has a dipstick arrangement, accessed via a rubber bung which is cleverly hidden on top of the gearbox. Which in turn is accessed behind the centre console, pull back the carpet on the passenger side (RHD car) there's a gap behind the console which is meant to provide the required access. As mentioned, there are You Tube video's which will help you with this.

One word of caution, always remember to refit the drain plug before filling up

An oil gun is very useful for gearbox/axle oil filling. I use one for the gearboxes and axles on my Land Rover. Full, the guns hold about half a litre.

Hello Tim
Having done this job recently on my 74 B I would add the following to already good advice.
The dip stick is a real pain to get to and remove on the the gearbox. when you eventualy do get it out, tie a loop of thick sting to the dipstick. It will make retrieving it a lot easier.
Before you start you need to order a new combined filter/gasket(P/No37H1942). It is easy to change once the oil has been drained. 6 screws secure the plate in place. once removed clean the magnets in the cover and replace with the new gasket/filter.
To fill the geabox get a piece of hose approx 60cm long. Fit one end into the gearbox and attach the other end to a funnel. Tie the funnel to steering wheel using a cable tie . You can safely add 3 Ltrs of oil before you need to start checking levels.Before starting I would remove the foot well mats and put newpapers on the floor to minimise any mess.
Good luck
Mike Barclay

Many thanks for your replies, Michael Barclay did you also service the Low Pressure Valve as shown here http://www.mgb-stuff.org.uk/goc.htm ?

Hello Tim
Unless you were having problems engaging the overdrive prior to the oil change do not be tempted to remove the Pump or Valve.(both under the filter plate). They can be tricky to refit correctly and there is a chance your overdrive will not work properly once back together. Leave well alone.
Best regards
Mike Barclay