I think i have narrowed down my tranny problems. Do 4runners have seperate TCUs or are they intgrated into the computers? Another question is how do i run a check on the TCU? My 4runner won't shift to overdrive and when it does(very rarely) it stays there for mabye a mile or two then kicks back down for no reason.

Thanks for the advice again.

 

The pre 96 used separate engine and transmission control units. 96 and on have a single control unit.

You can get a factory shop manual and look up the problem in the diagnostic by symptom and run the diagnostic listed for that problem. You should be able to do most of it with a multimeter. It could be something as simple as a bad engine coolant temp sensor.

I had a problem with my converter clutch. The diagnostic led me to the converter clutch solenoid in the tranny. I swapped it out and all is well.

There are three solenoids. One for the clutch and two for the gear changes. The 4 gears are controlled by how many of the two solenoids are on at a time.

Good luck.

Gadget

www.GadgetOnline.com

 

Is your truck warming up normally? A stuck thermostat or an electric fan that runs too much will lower the engine temp to the point that the ECU disables the overdrive. This causes you to run at higher RPM's and brings the temperature back up to the range it is supposed to be in. This allows the engine to run more efficiently and cleanly.

 

That's pretty cool Gadget, I didn't know that!
Have yet to delve into the tranny as much as you have.

 

It does take a while to warm, like about after 15-20 min of driving. Where should the temp gauge sit normaly on a 4runner? But when the engine is warmed up, it idles funny, almost like a misfire of a bad gasket, but there is no mixture of oil and coolant in the system.

 

Could you have a thermostat stuck wide open?
Might actually be keeping the engine too cool.

 

This ain't normal. In Florida you shouldn't ever go over about 5 minutes at idle. Check your t-stat and fan controls.
Don't know about the temp gauge position on your model. Is the owner's manual any help (hey, it could happen!).

 

Didn't come with a manual. I thought it was taking too long to warm up and you metniod TW sensor, and it kinda fits. I had to replace the TW on my Honda when it idles funny, almost like a miss, but it was a manual. I going to order a service manual tommorrow. Fan controls? Where is the thermo and TW on a 4runner before i go searching for them?

Thanks