I recently put a new clutch in my 1990 240 never had a problem shifting but now it won't hold in reverse or fourth if you're sitting still you have to hold it in gear any suggestions

Just off the top of my head, is your shifter installed backwards? I mean, it has a kink in it which you likely noticed during installation and removal, so is it tilting towards the rear or the front of the car? It is supposed to tilt toward the front of the car, so if it were in backwards, it could be hitting the back of the hole in the transmission tunnel, a bit of a vibration and it's getting knocked back towards neutral. This stick should face mostly upward, nearly vertical, when in neutral.

Let us know if that's not it and we'll come up with more ideas. Good luck!

Ooh, or even worse, if you didn't mate the tranny up all the way to the engine (check your bellhousing bolts!), then it is sitting towards the back of the car a bit, again allowing the stick to hit the back of the hole in the transmission tunnel. Take off your center trim pieces and the rubber boots and inspect.

Transmission is fully seated and the shifter will only go one way. I took it out as an assembly. I'm thinking maybe I lost a bushing or something. I'm buying a new shifter and see if that helps. Thanks for your input.

I guess you mean the shifter came out as an assembly. Well, I think you want to remove, inspect and reinstall that shifter assembly. There does need to be a bushing on the ball part of the stick that goes into the control arm of the tranny. If the bushing is damaged, get one from Nissan, they're cheap and very good plastic (nylon vs PVC aftermarket crap). I think the issue will be quite obvious when you inspect and reinstall your shifter assembly.

But maybe you just want an aftermarket short throw. It won't change your issue, but it's an upgrade to spend money on. If so, consider getting the OEM bushing from Nissan anyway. The ones that come with the shifters are bunk and brittle. Maybe fancy ones from reputable companies are better, like B&M. I got Fidanza and that bushing was crap. Of course that was just the shifter stick, not the whole assembly.

Anyway, when you figure out why you can't hold 4th or reverse, please let us know what was broke or installed wrong and how you fixed it. Thanks.

I will. Thank you for the input!