Although the clutch friction material is designed to operate in an oil-soaked environment, 26+ years of saturation has most likely taken its toll. The overdrive should always be disassembled and carefully inspected before installation onto the transmission. These were only bonded on the later blue label overdrive units, instead of being riveted. Unfortunately, a broken annular clutch makes no noise at all. Post-1974 models have a side filler plug on the transmission, which is located at the proper level for a full transmission. An inadequate oil level will interfere with the function of the sliding synchronizer hubs, causing the transmission to shift slowly. pints with Overdrive), so if you have a leaky transmission, check the oil level often. Remember, the gearbox does not hold all that much oil (6 U.S. An alternate method is to use an old-fashioned oil squirt can. Feed the tubing into the tiny little hole in the transmission, and then slowly pour oil through the funnel.

The best way to add oil to these transmissions is to use some cheap plastic tubing with a funnel inserted into one end. Pre-1975 model transmissions have a dipstick that can be accessed by lifting the carpet on the transmission tunnel and removing a rubber access plug. Sometimes it is a matter of nothing more than insufficient oil in the gearbox. You might try replacing the oil in the gearbox with ATF oil to remedy the problem.Ī nonfunctioning LH overdrive unit can be caused by either mechanical, hydraulic, or, most commonly, electrical problems. After that if it doesnt work, your oil pump may be stuck down and there's no hydraulic pressure building up. Then try cleaning the filter under the large rectangular plate. Apply power to it while its out and see if it clicks. If you're getting power, remove the solenoid valve assembly and check to make sure its all OK and not blocked. Yeah I would start by checking for power. He said he checked the oil level in the gearbox. Since the key is below the OD switch lever on the steering column, I don't think that should have done anything.Īre you getting power to it? Try a test meter/ lamp from the inhibitor switch and work backwards to the main switch, and it's supply. The only thing I did in between Friday's drive when it worked and Saturday's drive when it didn't work, is that I oiled the ignition key slot as the key was getting stiff to turn. I've checked fluid level in transmission (20w50 Castrol) and it right on the mark. I've tried wiggling the shift lever in 4th gear to see if I can get safety switch (name ?) that is on top of transmission to engage.

I've tried wiggling the lever in different positions. Saturday morning I head down the highway and when I pull lever back to engage, nothing happens. MG MGB Technical - Overdrive doesn't engage? The OD on my 72B has be operating without flaw since I purchased 2 years ago.

Laycock j type overdrive solenoid