Help Low Oil Pressure

I just had a re-built transmission installed in my 95 PA with 104000 miles. (no indications, it just went). I got the car back today and when I stop at a light after it warms up, the oil pressure nosedives down to zero. Haven't had a chance to crawl underneath and check wiring to oil pressure sensor. The transmission mechanic noticed on test drive and informed me of the problem. my question, is there something they do when they change the transmission that would effect oil pressure? Any help would be greatly appreciated. Thanx

Is your oil level OK?

Not sure if you'll be able to connect a trans job with low oil pressure.

No, I can't think of any reason why a trans swap would affect the oil pressure. Check the fluid level, then check the connection to the sensor, and it that fails then your'e looking at either engine sludge build-up or the sensor went south (could have been knocked around a bit from the trans swap, but unlikely).

A Transmission job should have nothing to do with the oil pressure gage unless; the wiring harness going to the sending unit was damaged. I had to replace my sending unit recently, due to blockage of the orifice. The gauge was fluctuating all over the range.

Sounds sensor related.. My sensor quit, started reading occasionally and wrong. Its reachable and you can swap it out relatively easy. I replaced it in 30 min.

Good luck