ztim

This morning I bought a vaccum modulator valve because I was told that that may be the cause of a little white smoke coming out of the carburator area. Plus the transmission won't shift into second gear or work in reverse. My question is:

Where on the engine is the modulator located? I have an '84 Delta 88 with a 307. Thanks

72 cutlass455

On my th400 it is on the passenger side and is just visible. Be sure to attach it to the manifold vacuum not the carb vacuum lines. Mine is on the tranimission.

ztim

So it is on the engine up top and not on the transmission itself?

Lady72nRob71

If you have the stock tranny in this car, then it is most likely the TH200.
The modulators should be on the tranny itself.

The white smoke around the carb area is more likely from another cause, like oil leaking from VC gaskets burning on the exhaust manifolds.

joe_padavano

Which transmission do you have? The four speed 200-4R doesn't have a vacuum modulator. The three speed TH200C doesn't have one either. Only the three speed TH250 uses a vacuum modulator.

ztim

I'm not sure which transmission I have. The clerk at the parts store gave me the valve when I told her which car and engine I had. I looked up under the trunk lid for the service parts list, but there weren't any numbers/letters that looked like the one mentioned above.

joe_padavano

Let's start with the easy question - is it a three speed or four speed?

ztim

I think it is a three speed. I looked up an old post and found a transmission shop mechanic told me it was a T350. edit: I searched Yahoo using "Image" and found a TH350 Transmission with a picture. On the passenger side near the rear I saw what looked like the part I bought so I went out and jacked the car up and looked. It looks like the modulator. But then again I saw a picture on the web that captioned a (looks like) a "transbrake solenoid." ???

d2_willys

Look for the part that looks like the part you bought on the passenger side, toward the back of the transmission. It should have a vacuum hose going to it. When you find it, and are removing it, make sure that you don't lose or drop the actuating pin. It will either stay with the modulator or stay with the transmission if you are lucky. I normally put the pin in the new modulator and install carefully. Coat the modulator o-ring with trans fluid before installing. Good luck

joe_padavano

You don't have a transbrake solenoid, since that is a drag racing part not installed from the factory. You likely don't have a TH350 either, but a TH250. They look very similar externally. That would be the only trans offered in 1984 that used a modulator. As for the three speed vs. four speed question, what does your shift quadrant say? Is it PRNDSL or PRNODSL (with the O actually an O around a D)?

ztim

Thanks Joe. All it has for a selection is: P R N D 2 1

I don't think it has overdrive.

ztim

I found directions on a DIY site that tells how to change the modual in a Ford Truck. It says the vacuum modual is on the passangers side of the transmission in the back. It said to loosen the bracket holding the modual in and take the old one out being careful not to drop the pin and then putting the new one back in its place.

Does this sound about right? I think the modual on my 88 is about the same.

Danny Wiseley

The part you bought is the modulator. The "pin" being referenced is the modulator valve, which is operated by the modulator. Neither item is going to fix your transmission if it won't go in reverse. It needs to come out for an overhaul. Sorry.
DW

ztim

I figured that. I just want to see if it will fix the shifting problem from 1st-2nd.