Hello, two weeks ago I bought a 5 speed which I was told was a 280z 5 speed but the bell housing is diiferent than the bell housing on my 4 speed(the gear casing and bell housing are one piece ont the 5 speed).They told me that the bell housings were interchangable. Well, today i tried to change them out ,but had no luck it seems the selector rods are a diiferent dia. and will not fit the gear box casing from the 4 speed .What's going on? Do I have the wrong tranny? My friend says it's a truck tranny.Can I still use it?

I've installed 2 5-speed gearboxes so far and have had no issues. Do you know where the gearbox came from?