In one of the threads about towing with an auto tranny, someone suggested using the "OD Off" button to keep the tranny from hunting. It seems to me this would be good up to about 30 or 40 mph, but above that you'd be turning some really high RPM's in 3rd gear. My question is, has anyone ever tried modding the "OD Off" circuit so that it only drops to 4th gear, like it does when going up a hill? My daily drive is on 45mph 2-lane with very rolling hills, and I'd love to be able to disengage the lockup and just keep it in 4th gear. Thanks for any info!
Auto trans lockup question??
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4th gear is overdrive and the tallest gear. At a certain throttle position the torque converter is unlocked. (this prevents lugging).dave02dc said:
Runningwith the OD off at 60 mph only yields around 3k rpms for me(maybe a few hundred less don't really pay attention). Not really screaming. With the OD off the torque converter will stay locked for longer periods and keep the tranny fluid cooler. All that hunting and shifting builds up alot of heat. That is why the factory manual says to turn the OD off when Towing.
Let me put it this way, Higher Revs with less load is easier on your engine than lugging. It's also easier on the tranny to keep the TC locked and not searching. Try your drive with the OD off. If your transmission is shifting alot on that very easy slow drive and you are unloaded it's not much to worry about. If you want to move the shift points to a higher RPM use the ECT button. If I am In town and not breaking 50mph I usually keep the OD off out of personal preference. Try it and see what you think.
I've used the ECT button before, but I'll "occasionally" hit 55 on the downhills, so I'm back into lockup. I did try the OD off for a while this morning, and was turning 2700 or so at 60mph. Guess it seemed so high compared to the 1800 or so I'm turning at 50 in lockup, but you're right - it's not really screaming. I don't have any problems going up the hills in OD with the lockup disengaged, so I thought I might try it if someone had a procedure to make the change. Thanks for the info, though!
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Unfortunately I can't think of any way to remap the shift points that are within the common mans reach. if you don't look at the tack you can hardly tell if it's locked or not It could be worst, 
We could have 3 speed autos !
We could have 3 speed autos !I don't really want to remap the shift points, just selectively disable the lockup solenoid. Maybe I'll look in the wiring diagram to see if there's a simple way. Only thing is, I'm not sure if manually turning off the solenoid (vs signal from ECU) would cause some other problem with the trans. I sure as hell don't want that!!!
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