I am not sure. Usually you can install the newer tranny into older cars... I
put in an 88 tranny into an 84 and all I had to do was change the tailpiece
as newer one is bigger.

Newer tranny shift so much better... so much more responsive.

According to reference in Adsitco.

Your car is 722.403 and newer diesel is 722.414

Gas engines are
84-86     722.400
87-93      722.408

6 cylinders are different.

So you can install the 722.414 but I do not know if gas engine would work. I
suspect the gearing is all different but the tranny itself will bolt up. The
vacuum modulator would also be different.