What are the symptoms of a bad vaccuum regulator on an 88 A4LD?

 

I meant vacuum modulator. From the way they've been described, I would imagine that they might cause the transmission to shift high and hard, and cause a vacuum leak and make the engine do weird things, too.

 

I seem to remember one of my cars with a non-functioning vacuum modulator would shift way too early, so the engine would strain, and the transmission was probably slipping a lot. On another car, it would not shift out of first gear. On yet another car, the shifts were occurring, but very harsh. So I've seen all sorts of responses.

 

Yeah, I'm getting harsh 1-2 shifts, and dorta high shift points, but no slippage. Being that close to the exhaust CAN'T be good for the rubber parts or the vacuum line!

 

Easy way to tell if the modulator is bad is to pull the vacuum line off and see if it is full of tranny fluid. If so, it is bad.

 

careful pulling it out to change. small steel actuator pin that's easily lost in the inner end.

 

What would happen if this pin is lost/not installed?

 

The modulator will not work in any way and you will need to buy a new pin from the dealer. I lost that pin inside an Explorer of mine years ago......

 

Yeah...I replaced the modulator and lost the pin, but Fordor, the god of Aerostars blessed me, and I found it on the floor...in the oil dry...almost swept up. The funny pary is that it shifted into all four gears, but slipped like it went into noodle on the 2-3 shift, and then caught.

 

I recently re/re'd the vacuum modulator, gave the trany a gentle flush, new filter and very carefully adjusted the fluid level to just right. All shifts became smoother and more efficient. The trany wasn't operating badly, but it became noticeably better with the servicing.

Cheers, Mike

'89 EB Ext. Aero, 3.0 auto.

 

Yeah, I've done all that except the gentle flush, and the shifts are much better. Still going to replace the rubber vacuum line to the modulator at the transmission end...just need to get some.