The 95 probably has a broken spring, VERY common in 95 and not so hard to fix.
But if ya really wanna swap (and the 98 trans is perfect!) then its fairly direct. To save hassle you will want to remove BOTH engines and then swap over the valve covers and the intake manifold with IMRCs (intake manifold runner controls) which are located right under the intake. You will also want to swap over the 95 main engine wiring harness over to the 98.
Now if you want to make it more or a pain, you can convert to COP to get rid of all those spark plug wires. Its pretty easy to do with the engine out and then you also will not need to swap valve covers.