Fairly sure the Z34s had the HM 284 Getrags for their 5 speeds, and the typical 4T60s for their autos. Not 100%, but on up past 90% sure.
As far as replacing the solenoid, you get to have the fun of tearing into the side of the transaxle in order to get to this magic beast. Its not hard, but rather is a lot of things to unbolt, support, remember, and keep track of.