Automatic Transmission Problems

[alex4]

The problem:Alright, I have a 93 240 with an auto trans with 144k miles. Occasionally, it will stick in first or second and not shift up. I will rev the engine to redline and the car's speed does not change nor does it shift. As I rev the engine after it doesn't change, I can feel when it hesitates to put gas to the wheels or something. It will just idle along, not speeding up or anything around 30-40mph. *shrug*It does not do it very often, maybe once a week of daily driver-ing around town. It's been doing this for a month or two (though I've only owned it for 3 months)Option 1: I took it into a transmission shop and they pulled the pan. The pan had lots of little gold metal shavings in it. They said that to fix it, they would have to rebuild the transmission costing upwards of 1000$. (700$ labor + parts).Option 2: In a scrap yard, I found an automatic transmission from a 95 240SX for 350$ with 80k miles. My question here is how would that transmission do in my 93? I know that mechanically the S14 is pretty similar to the S13, but would there be ECU issues, mounting issues, wiring, anything like that at all? The transmission shop said it'd be 400$ to install an identical transmission, but I don't know how different it would be in a 95.Another option is to just keep driving around on my partially broken transmission and hope it lasts until I can afford a 5 speed swap. Anyone have a price estimate on all the parts for a manual conversion?My usual car service garage who I trust said that it would probably make it worse to flush the fluids and put in a new filter, and they recomended the trans shop that told me it needed to be rebuilt.Thanks!!

P.S. Yes, I know, everyone thinks I need to swap to manual. I do too, trust me. But since I can't really afford that, let's consider the other options too!