VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Need help installing a vacuum diaphragm in 1951 cast iron transmission

There is oil in the vacuum line of the powerglide so I’m assuming the vacuum diaphragm is cracked. Once old diaphragm is removed can the new diaphragm be installed with transmission in car. Or does the plunger and body need to be in the up position for parts to line up. Besides the 1949-53 shop manual Is there a better manual that shows step by step on how to replace diaphragm. Thanks for your help.

Just remove the bolts, cover and spring and keep the valve in place. Put eveything back in the original place and it was always done with the transmission in the car,
When the modulator leaks (vavuum) you usually get a lot of blue smoke from the exhaust.

Thanks, that's the way my schematic shows but did not know when cover is removed if the valve would shoot out.

If anyone is losing prowerglide trans fluid try replacing the vacuum diaphragm. I did and it cure my fluid loss.