92 topaz, speedo erratic, will not shift out of 1st

92 Topaz, never had a problem b4 with trans, all of the sudden last nite was driving it and speedo started jumping up and down, seemed to huddle around 15 mph, and car revved a little and slowed down to 1st gear. Then would only move forward in 1st, go approx. 15 mph or so, but would not shift into 2nd or 3rd. I let it sit for a little while ( maybe 30 min.) and it seemd fine for about 2 miles and then back to what it was doing b4. could it be the speed sensor?? fluid level is perfect.
HELP

Si

Sounds like a speed sensor, but the transmission is not electronicaly controlled in that one. Pull the speed sensor out and inspect the gear. Check the gear on it and look into the hole where it came from and check that gear too. They are all plastic. If there are signs of wear you will have to replace the speed sensor gear, the differential drive gear and the govenor gear.

Hi, I just want to say I was having the same problem with my 92 Murcury Topaz and as I was working on it i pulled the trans pan off and found a like yellow plastic gear broken in the pan. After looking arround by the spider gears and so on I seen where it came from and am now trying to replace it. I pulled the full CV axle but havent been able to disconnect it from the spider gear area. There must be a pin there hold the spider gear in place. Im sure once the spider gear comes out there will be a retainer clip holding the axle from coming outand then I'll be looking at repleacing the Broken gear. The other thing is that when the plactic gear broke it damaged the goveror gear also so Ill have to replace it to.
Can anyone tell me what Im doing? Too much/Too little?
Good luck bud and do let me knoe how things are going as the problem sounds to be the same