My 79 300SD has a shut off problem. In tracing the vacuum lines, it shuts off fine when I disconnect and plug the line going to the tranny. I guess that means there is a leak in the vacuum modulator. Could that cause the tranny to slip in high gear?

One other question: When testing the functioning of the shut off valve, I noticed that I could shut it off with my vacuum pump, but it took a lot of pumping and it was not building vacuum very well. Is this a problem?

__________________
Richard

"Die Schadenfreude ist die reinste Freude"