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MG MGB Technical - D Type Overdrive Help

My early type D overdrive refuses to shift into overdrive. I have checked all of the usual things, and the solonoid is working properly, the operating lever is adjusted properly, the oil level is correct and the overdrive isolation switch is working. Tonight I pulled the cap on the operating valve and removed the spring. I found that not only does the valve not move when the solonoid is activated, it doesn't even move when the operating lever is moved manually, so it would appear the valve is stuck. Does anyone have a suggestion as to where to go from here? I really don't want to pull the engine/gearbox as the weather here is finally turning sunny and I don't want anymore down time.

Thanks - don
don scott

Cleaning the filter and running with ATF is often recomended. A lot of o/d problems can be fixed without taking it out of the car though if you can get to an expert with a vehicle lift.
Stan Best

Hi Don:

Contact John Esposito at Quantumechanics, Monroe CT. John is an expert with D types. He has a web page, and he may help resolve you problem.

Good luck, Rich Boris 67 B roadster
Rich Boris

A sticking valve can normally be handled without pulling the overdrive. There's an access plate on the bottom that contains the filter, I'd first drop the filter to see if there's a crud issue or something. You can actually remove and reinstall a great many hydraulic parts from below. Clean as you go, check that the springs and o-rings are in decent shape, and hopefully your culprit will be found in the process. Normally you don't have to pull the OD except to replace, say, a unidirectional clutch or something. It does happen, but seldom. Clean your workspace, and have a manual and a source of replacement parts at the ready, and go through all the ports that can be reached from below, and with a little luck you'll get it done.
Sam

This thread was discussed between 10/06/2007 and 17/06/2007

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