BW auto transmission abnormal behaviour

[jagwit]

My S3 with the BW auto is acting up. When I drove the car into the garage with the previous trip, all was fine. Upon commencing the drive on Saturday, the transmission was acting up. “Broke” in the garage…

Symptoms are as follows:

1. Goes into D or R very harshly at idle;
2. When going into D, it actually engages 2nd;
3. Stays in 2nd until I exceed about 55mph (90km/h);
4. Can manually select 1st, and then 2nd when driving, but does not go into 3rd when selecting D unless speed exceeds 90km/h.

My guess is that the vacuum modulator is not working as it should or that vacuum is not applied to the modulator?

Can the vacuum modulator be removed from the transmission from under the car?
Can the vacuum modulator be opened and serviced?

[jagwit]

So…

It turned out it WAS the lack of vacuum to the modulator that caused all the above. But there were two causes:

1. The vacuum line that T off from manifold vacuum which feeds the modulator and also goes directly to the distributor vacuum advance diaphragm, was actually plugged into the vacuum feed pipe, instead of just being open to atmosphere. (Yes, I am one of those dumb, uninformed id10ts that does not understand why ported vacuum is the only way things should be…)

2. It would also help if the vacuum advance diaphragm was not completely perished. I sacrificed my wife’s dish washing gloves to fabricte a new diaphragm.

Now things are back to normal! Its been bugging me that the car has been a bit lethargic with light foot driving, whereas its always been nippy. Coolant temp has also been at least a needle width higher than what I was used to. Fuel consumption was also noticeably more. Now I expect all this will be back the way they were.