I replaced the vacuum modulator on my TH400 trans last year with a B&M adjustable version. I have the transmission pan off at the moment to hopefully fix a leak I’m pretty sure was coming from the front edge of the pan/gasket. Anyway, while the pan is off I removed the modulator to adjust it slightly.

I’m putting it back in place and my question is whether this looks like it’s seated correctly or if needs to be pushed further in? The o-ring is in place and I tried getting the modulator to seat further in by leveraging a screwdriver between the exhaust pipe and the modulator body. But it won’t go in any further so I installed the bracket that holds it in place. Any thoughts?

Separately, is there any need to use thread sealer on the trans pan bolts? I understand it’s not like the oil pan with certain bolts that the oil tends to wick down. I have the Moroso pan and gasket. A nice bit of kit.



Modulator pushed in as far as I could get it.

Bracket in place.

The B&M version I’m using.

 

Looks OK from down here.

I have never studied that at all. Push it in, bracket on, bolt in, exhaust back on, drive away.

I have never used thread sealer, and had no issues, but, I dont run pan gaskets on any of them.

 

Its been awhile but that bracket might be upside down. Its a th400 transmission so lots of info online about it

 

Is the bracket cracked right at the bolt? Looks funny.

 

The bracket is correctly orientated. No worries.

 

The vacuum modulator looks OK. The bad news is that the leak at the front of the transmission may be coming from the large O-ring that seals the pump to the case. It's not a very difficult repair but it does require removing the transmission from the car. Yes, I have been there and done that.