is there a fuse that connects to the transmission that controls the overdrive or allows it to work?
1986 automatic 2wd

 

i can't figure this out i went to take it to a transmission shop and they wanted to charge me 250 for a diagnostic test to see what exactly was the problem i believe it is a relay or something because the po(my grandpa) said that he had a problem with it before is there a procedure i should take to try and diagnose this myself.
ANY IDEAS????

 

I think there is a separate computer for the trans and if i remember right there is 3 temp sensors on the motor. one is for the trans. it keeps the truck from shifting into overdrive until the motor is at operating temp. they are on the intake fairly close to the thermostat housing. the other two sensors are for the gauge and engine computer. i have a toyota book for the 86, but i can't find it, if i do locate it i will check about a fuse.

 

There is a seperate control box for the trans and i believe its located under niether your radio in the center console on the floor. Is that the only issue ur having with the trans? If so you may just want to check the switch for the over drive. Check connectors and wires. You can check your fuses but i'm sure totally if theres a fuse for only over drive or if it runs through another fuse. Start pulling fuses and see if they are all good.

 

its an auto right? u got cruise control? If so, take 2 min and disconnect the cruise control ecu, it is located behind the drivers side kick panel above the fuse block. when mine went out ( it was submerged in 35*f water for over 12 hrs) it kept my tranny from goin into o.d.
If its not the problem, it only takes another 2 min to reconnect and cover it up.

 

Ya that is the only problem i have currently. I don't have cruise control and the bottom does indicate that overdrive could be on and is turned off when you push the button. How would i check the temp sensor i looked in the fsm and it says to check the continuity but i don't have a voltmeter available (im at school). Is there anyother way to test this or would it almost be just as easy to just replace it?

 

now that i'm thinking about it i think it might be the temp sensor becuase it would shift into overdrive directly i could go right to a highway next to my house and it would go into it directly now im thinking that it might be sending the signal wrong. is it possible that it is doing the opposite thing it used to be doing?

 

i don't know of a way to check the sensor without a volt/ohm meter. you could check the connection to see if it is dirty or broken. it would be better to test it before buying a sensor,it can get expensive throwing parts at a problem.