Having trouble with my overdrive. Replaced the solenoid, now thinking it might be the relay Where is it located and is it some thing I can replace myself. Could I cause more damage by driving the car?

 

what model, year car is this?

re: damage, that would depend on what sort of overdrive you have and what trouble you're having with it. is this a 4-speed manual with overdrive, or an automatic with overdrive?

 

1991 240 wagan, automatic w/overdrive, very sluggish @ 40mph. Before and after solenoid install.

 

well, if the OD is not engaging, then you'd be zippy at 40 as you'd be in 3rd.

find some open road and roll smoothly from a full stop and count the gear shifts, there should be 3 shifts, the last one occurring right around 40-45 if you have light throttle acceleration.

does the dashboard yellow OD uparrow light toggle each time you push the button on the shifter ? if you're cruising at 45 or 50mph in D, do you feel it shift up/down when you do that ? if so your OD is working fine.

 

The arrowup light stays on, when I hit round 40 mph it kinda chuggs like it quite can't get there haha is the best way I can put it.

 

ok, when the light is ON, the OD solenoid should be de-energized, and the OD should be disabled. with the light stuck on, the OD would be off, and your car would be in 3rd, but you should be able to run it up to at least 70 or 80mph albeit at high RPMs, requiring liberal application of the throttle you can't overrev these engines.

does your car have a tach? 40MPH in 4th gear (OD) would be about 2000 rpm, while 40MPH in 3rd gear (drive without OD) woudl be closer to 3000 rpm.

you said you replaced the OD solenoid, so you must have found the connector for it. connect a volt meter between the wire to the OD solenoid, and a chassis ground, when the OD light is ON, that wire should NOT have power, and when the OD light is OFF, that light should be powered.

if this is the case, then your problem is something entirely different. your lack of power may be due to an engine problem. is the 'check engine' light on?

what does the transmission fluid look like on the dip stick? it should be clear red, or at most very light brown. if its dark and/or smells burnt, you should flush and change the ATF.

the transmission 'kickdown' cable needs to be properly adjusted, this comes off the throttle spool and goes down to the transmission. check it with the car off, with no gas pedal, there should be about 1/8th inch of gap between the little crimp stopper on the cable and the orange cap on the adjuster ferrule, and the cable should be ever-so-slightly slack. shortly before full throttle (Gas pedal floored), you should feel a 'notch' which is the kickdown cam in the transmission and there should still be a little more pedal travel after that notch.