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MG MGB Technical - How to change gearbox oil?

How difficult a job is it to change the gearbox/overdrive on an MGB-GT?
The drain plugs are easy enough to get to but I cant see any way to access the filler/dip stick (I'm not even sure where it is?).
Can this job be done with the gearbox in the car or does it need to be removed first?

Thanks!
ormsky

On early MGB's the dipstick is on the top portion of the transmission casing and the access opening to the transmission dipstick can be found on the transmission tunnel directly behind the radio console and ahead of the heater outlet tube panel(accessable from the right or passenger's side with a LHD car.....often this may be covered with carpet and hidden). A round rubber filler plug of approximately 2" diameter fills the hole and once it is removed you can just get your fingers in to grasp the dipstick and remove it. Either a funnel with a long flexible spout on it or a normal funnel with a piece of tubing firmly attached to it can be inserted through the tunnel opening and into the dipstick hole. Transmission oil may then be added and it might be best to alternate between adding oil and checking the level periodically to assure a proper fill level.

I am not sure when the dipstick was eliminated but believe it may have been at or shortly after release of the the rubber bumper cars. My 1978 had a second plug up on the side of the transmission and I seem to rememeber filling throught the same rubber plug opening in the tunnel but to the side plug instead of the dipstick hole. Possibly a current rubber bumper owner might shed more accurate light on this.

Drew Hastings

Drew Hastings

Ormsky
The dipstick/filler is at the front of the gearbox tunnel under the carpet behind the speaker (or radio on later models)and accessed via a rubber grommet.
The gearbox does not have to be removed but you will need a funnel and pipe to refill using 20/50 engine oil.
Your local MG club meet near to you. If you have any problems call at one of the monthly meets. http://westlancsmg.co.uk/
Robert
R J Collier

Thanks for the replies, I'll have another look tomorrow!
ormsky

ormsky

Recommend you check you local parts shop for a funnel with a valve. This makes adding the oil a bit easier. Also, have a towel or newspaper on the floor and tunnel.

This is one of those contortionist type jobs. Have to hold the tube inplace and then either pour the oil in or open the valve to allow the oil to flow in.
BEC Cunha

And if your car has the later side-fill box, make sure the filler plug WILL come out before you pull the botom plug and drain the contents.

Regards
Roger
Roger T

For around $5 or less you can buy one of those plastic hand pumps. This makes life much more easy. Hardwareshops and auto shops have them. Usualy a red squeezable polypropylene plastic "handle" a couple of flap valves and two semiclear plastic tubes.
I fill my gearbox from the side ('75) and some form of pump is necessary.
P.N. Sherman

I love the oil cans with the flex tub and squeeze pump handle. I keep one with 20-50, one for tranny fluid, one for shocks, and one with brake fluid. The end is a thin tube that is perfect for filling shocks. Adding just enough is much easier. The cans seem to hold about a pint each. Check old hardware shops or harbour freight, maybe even ebay.
kids1

Ormsky

This may help here are some pics of accessing the gearbox dip stick.

http://www.mg-bgt.co.uk/gearboxoil.html

Steve
Steve99

If you don't have one, I recommend getting the Bentley manual for your car. It has lots of diagrams.
Chris Betson has a repair manual available on his site. http://www.octarine-services.co.uk/ click "enter my forum" to find many technical articles and a repair manual.
Kimberly

This thread was discussed between 24/02/2007 and 25/02/2007

MG MGB Technical index

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