No vacuum to transmission but brakes work fine
 

I just got the car back from the transmission shop for some routine maintenance and an adjustment on the transmission because it was shifting hard.


The guy said that there is no vacuum at all going to the trans. the vac pump is good because I have brakes that work fine.


Any tips as to where I should be looking around first?


car is a 190d2.5td

I don't see how but maybe the line is blocked. If the line was blocked there would be no vacuum leak.

Also perhaps the transmission vacuum valve is no good any more.

On my 84 300D there is an plastic orifice stuck in the vacuum hoses before it gets to the Transmission Vacuum Valve.

When I had no Vacuum to the Transmission Modulator (I had disconnected the line with out knowing it) the up shifts were nearly the same but the down shifts were sudden and harsh.
Also I don't recall the disconnected line causing any breaking issues. Between the orifice and the Transmission Vacuum Valve which is a variable orifice I guess there is not enough vacuum loss to effect the breaks.

On your BUFO, there are four vacuum connections. The one that's top center is vacuum, first check that. The one on the bottom nearest the edge is the variable vacuum signal from the VCV, measure that and make sure it's varying with throttle position. One or the other of those will be your problem.

Have you checked that you have vacuum? The brakes can still work without a vacuum source present.