There is no adjustment for the bands on a Chevy automatic transmission. They self adjust as the bands wear.
Get the trany checked at a trany shop.
Automatic Transmissions are such complex things that I would leave that to a transmission shop to do or, if I needed a new Automatic Transmission I would purchase a used or rebuilt one and replace the bad one myself.
Worn bands Dirty/burned fluid Plugged filter
a 3.0 lt will fit you just have to change the bell houseing
The DeVille could have low transmission. Or the internal transmission bands or valves could have failed. The transmission will most likely need a rebuild.
I would be glad to get you a good answer and instructions on how to adjust.However could you provide just a bit more information on what you are trying to adjust/or what type of change you are seeking?
On your 1992 FORD TRUCK AEROSTAR 4WD, the NEUTRAL SAFETY SWITCH is: UNDER VEHICLE, CENTER, BELOW SEATING AREA, MOUNTED ON DRIVER SIDE OF TRANSMISSION info obtained from www.autozone.com
transmission is in but cant get linkage right. photo would help
I believe that begining in about 1993, the transmission came electronically controlled. At a minimum, the valve body would have to be changed. It is better to find a unit form a 1990 to 1992. 1989 and earliers had a different shift linkage. The bellhousings are different between 2.9L and 3.0L engines. The pump is part of the bellhousing, therefore some disassembly of transmission is required. DO NOT attempt this if you are not familar with transmissions!
That would be 21 gallons.