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Speed sensor!

This is a 92 ford tempo with shifting issues. couldn’t get it out of 1st gear and speedometer was immobile. so we opened up the tranny to find the speedometer drive gear chewed to bits. we replaced them and put it all back together. car worked fine… for about 5 miles. speedometer still works but now it won’t shift up again. replaced the speed sensor, car worked fine… for about 5 miles. same results. cant figure it out. driving me insane.

What “same results”? What happened the 2nd (or, 3rd) time?

the car wouldn’t shift out of first gear. this time, however, the speedometer continued to work (unlike initial failure), ruling out the speedometer drive gear (connected directly to the speed sensor and speedometer cable).

Are the sensors getting filled with transmission fluid? Have you tried removing and reinstalling the same sensor? Are you positive you are using the right sensor? (Maybe the voltage output is too low for your application?)

no, it went in clean and came out clean. re-installed the original once , then replaced it with a new sensor when it happened again. the speed sensor is defenitely the correct one for the car, double checked it. just trying to figure out why it works for a small amount of time, but fails eventually. I don’t particularly want to buy another, just to have it happen again.

going to pull it out and put it back, see what happens. after that i guess ill take a look in the tranny again. i guess it could be a short, but it seems like it could be simpler than that.

After a few minutes of driving, the transmission might start to go into second. If it dies that, things are not improving and the transmission will have to be rebuilt. With all the other things that need attention on a 92 Tempo, it is not worth rebuilding. If you do get it rebuilt, change the planetary gearsets because they can come apart with age, and you don’t want to fix it a second time. The transmission may even work well for a while when warmed up, but you don’t have long.

but it shifted fine earlier(once after replacing the speedometer drive gear and then again when we replaced the vss) , kindof ruling out a shot tranny. we checked the tranny when we had it out and it seemed cool and the gang. running normally until the vss stopped working again.

besides, after it stops shifting out of first, i can’t get it into second at all. we had to drive it home in first (2 miles or so) so i’m having trouble believing that its a tranny problem.

sensor too close to flywheel?

after driving it a couple of times, a pattern emerged.
drives fine when its cold and after a couple of miles (even if the temp doesn’t increase too much) it will start to miss second gear and rpms will rise quick with a soft whine sound. if i’m soft on the throttle, it might fall into second gear but not for too long. if i’m not mistaken this is the transmission acting up, not the sensor(s). Am i terribly far off base?