My 3vze's overdrive stopped working and for the past two years she's been in and out of mechanic shops. The mechanics say it's temperature-related and I agree with them, as I can see the temperatures drop until they hit about 160 ish (it hovers at this temp on the highway), then overdrive cuts out. I installed a brand new fan clutch and a brand new 195 degree thermostat (stock is 180) in there and it still will not maintain a high enough temperature to engage overdrive. Is there any other way I can increase the temp of the engine? is there any way to trick the computer into thinking it's at a higher temp? It seems like nobody else has had this problem, because these engines seem to be so prone to overheating. If y'all can think of anything, I'd really appreciate it. I've given up on trying to pay someone to fix it because I'm about 2k in the hole with this one with nothing to show for it. I'll try anything at this point.

 

I believe one of the temperature sensors greatly effects shifting into O/D or not, so if you're truck isn't getting up to temp(how do you know exact degrees?) then it will not shift. There should be multiple threads about this topic if you search. Use the "google" option under search, not the other ones.

You shouldn't have to trick the computer into thinking it's running hotter, there is something not operating properly that is causing your temp issue. Every mechanic has just missed it unfortunately.

 

Aren't there actually two temp sensors on the 3.0?

 

There are two. One sends a reading to the gauge in the dash. The other sends it to the computer. I've replaced the one for the computer and installed an aftermarket temp gauge to get somewhat exact temps.

 

I have installed an aftermarket temp gauge. the temps may not be perfectly exact but it does give me a good idea.