Geo Part-time automatic transmission

geo
transmissions

#1

I’ve got this 87000 miles 3-cyl '94 Geo Metro with an automatic transmission which only works every other day. The car is in great shape, gets great mpg, except that today it won’t shift up or down. I have to manually move the automatic shifter up or down. Tomorrow it works like a champ. Works great for days then it doesn’t. I took it to a Japanese car repair joint and they didn’t want to touch it. I’d like to think that its just a loose connection or a hole in a vacuum line somewhere. What do you think?


#2

Gee, people pay a lot for cars with that feature! Are you sure you want to fix it?

But, to clarify, what exactly does it do if you put it in “D” and try to drive off? Are you saying it lugs as if you’re in 3rd gear, but if you manually shift it down into “L” or “1” that it’ll accelerate normally?


#3

That’s exactly what it does. And then I shift into second and then “D”. Also when climbing a hill I have to manually downshift it. But it doesn’t always malfunction. Today I drove it to work and back and it worked perfectly.


#4

Some research on Alldata indicates that this is a electronicly shifted three speed transmission. There appears to be two shift solenoids for the 1-2 and 2-3 shifts. I could not find any information regarding the ‘limp home’ mode for this transmission. The ‘mode’ might be to command third gear starts but allowing manual selection of 1st and 2nd. Your owners manual might mention something about this. Also, Is your Check Engine light ‘on’?

The Electronic Command Module for this transmission can be scanned for trouble codes so you might run the Metro by a transmission technician to see if any codes are set. The ECM for this transmission does not seem to be as comprehensive as later Transmision Control Modules as it does not modulate line pressure electronically – the transmission valve body has a Throttle Valve (TV) spool the cam for which is probably connected by a cable to the throttle body. The problem may be a sticking or leaking 2-3 solenoid. This is accessable after removing the pan. If this needs replacement, make sure you get a filter replacement, a cleaning of the pan, and maybe a flush of the transmission.

Get back if you find the definitive solution to this problem and if you get any additional information from your mechanic.

Researcher


#5

The check engine light does not come on. I’ll have this checked out. Thanks for your response.