When is it a good time to use O/D on my 1998 Tacoma 2.7L?

I have a 1998 Tacoma 2.7L 4WD. I want to know when is it good to use the O/D?

 

OD is basically 4th gear. It should be used all the time.

 

0 to 40. Or rack that mofo up to 60 and then take it out of OD

 

It should be on all the time. As far as I know you should only have it OFF when Towing.

 

This^^^

 

You're asking the wrong question. The correct question is "When should I NOT use the O/D?".

Overdrive is always to be used except when under heavy loads such as towing or hauling or generally when more power or torque is desired. Using overdrive under loads for too long will burn up a transmission and leave major damage.

 

I echo what @CodeSeven said and I have a video to demonstrate when it's good to keep overdrive off. In case you don't want to watch the video, it's when you're climbing steep grades or towing and you're at the speed (around 50-60) where your rig can't just cruise in the overdrive gear (4th gear). The trans keep downshifting to 3rd from the throttle response needed to get up the steep grade or slight grade when towing and this is when your trans temps begin to rise. By turning off overdrive, you lock up the torque converter and you'll see at least a 20 degree temperature drop. You'll need a scan gauge or OBD II Bluetooth reader sending info to a phone app like Torque Pro to see this change or you can watch the video below and then become a believer that it works. The sun wasn't cooperating when I shot this video but if you watch closely when I'm pointing the camera at my phone, you'll see the temps rise and fall when I turn OD on and off while climbing a grade.

<iframe width="560" height="315" src="https://www.youtube.com/embed/BEZfDOkGVno" frameborder="0" allowfullscreen></iframe>

 

Is it because the higher revs are forcing the fluids out of the tranny and into the radiator?

 

Thank you guys!!

 

No, that's not it. The flow of fluid from the trans to the radiator cooler is a constant flow just like the engine coolant from the engine to the radiator. It has to do with whether the torque converter is locked or not when you're in between 3rd and 4th gear.