QuestionQUESTION: Hi there. I have started driving my 1978 MGBGT after 2 years in the garage. It runs fine but the overdrive does'nt work. When driving, i click the overdrive button and nothing happens but when i take my foot off the accelorator the overdrive feels like its trying to kick in. I have been told there is a dipstick somewhere to put gear oil in but cant seem to find it. Any chance you could send me a diagram. I have the Haynes Manual but still no luck. Also, after the car has been running for a while and i turn off the ignition the car wont start. I have to wait about half an hour for it to cool again. Any ideas. Cheers. Mark
ANSWER: The overdrive has two problem areas. It could be either.
1) The switch on the gearknob is small and weak. They often fail. Also the wires to the switch often fray and break internally. I would take the cap off and temporarily wire in a second switch, leaving it lying on the passenger seat. Then drive the car, and when the overdrive refuses to switch in, try the separate switch. If the overdrive now works, you have found the problem.
2) After two years the solenoid could have stuck. Underneath the gearbox you will find an oblong plate held by 6 small bolts, and a smaller square one held by 4 small bolts. The solenoid is underneath the square one. First you must drain the gearbox.
Take the solenoid plunger out, clean all the sticky oil off, clean the hole it came out of, and put it back again. If you are really brave, you could replace the tiny O-ring on the end. Also, take off the oblong plate and clean the filter that is underneath it. Then put that all back and refill the gearbox with fresh 20W/50 engine oil. It takes 6 UK pints (nearly a USA gallon).
Your late-type gearbox just had a combined filler/level plug on the side, accessed from underneath the car. There is no dipstick.
If you can send me more information about your car, I will deal with the hot starting problem separately. I need to know whether you have a UK or a USA vehicle. Does it try to start but misfire, or is it completely dead? Can you hear the fuel pump ticking when you first turn the ignition on?
The manual you need is called the MGB Repair Operation Manual 1978. Part number AKM4070. I happen to have a spare one if you would like it.
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QUESTION: Hi thanks for your advice on me overdrive i will give it a blast. my mg is a uk vehicle when trying to start when hot it is completely dead and i can hear the fuel pump ticking when ignition on and i would very much like your mgb repair manual 1978 thankyou mark.
AnswerNext question. Does the starter motor work, but the engine won't fire, or does the starter motor do nothing?
If nothing, lift the bonnet, drop the driver's door window, make sure the car is in neutral with handbrake on. Now operate the starter from outside the car using the ignition key. Can you hear a click coming from something near the fusebox as you turn the key?
Send me a PRIVATE message with your contact phone number, so I can organize the delivery of the book without making your number visible to the world.
