: 1984 Coupe Deville Transmission Modulator Location

04-28-11, 11:43 AM
For some odd reason I cannot find the modulator on my trans!! Any help???

04-28-11, 10:55 PM
What mod are you talking about? What does it control?

04-29-11, 12:56 PM
After a highway ride 60-70 mph, when I come to a red light the car does not want to downshift to 1st gear very smoothly. So I changed the transmission fluid and it did the trick for two days but now is acting up again and I was told to change the transmission modulator. I have the new part which looks like one end plugs into the trans body and the other end is a nipple for a vacuum line. I have a 68 deville with a th400 and it's on the right front of the trans, very visible but on my 84 I can seem to find it.

04-29-11, 04:50 PM
The THM 200-4R (used in 1984) uses a throttle valve, not a vacuum modulator.

The throttle valve is located on the passenger side of the transmission and has a cable that runs to the driver's side of the throttle body. The valve could be functioning properly and TV cable may be that actually cause of your issue. It could need adjustment or replaced.

05-01-11, 06:14 AM
Thanks sven914 I'll give it a try.