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Discussion Starter #1
I normaly drive around town with the OD switched off on my 2006 LJ. I've read conflicting information on what exactly this switch does and the long-term ffect on the transmission.

Is it just a switch turning off the overdrive gear, or does it affect the locking of the torque converter? If so, does it lock or unlock the torque converter, and either way, what does this do?

Thanks,
 

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When OD is off which is when the light is on is for driving around town like redlight to redlight. When OD is on the light is off and that gives the trans an extra gear to drop the rpms for highway driving and better gas mileage
 

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When the OD is switched off your 42rle transmission will only shift up to 3d gear. Some people keep it off because the overdrive is geared too deep which could lug the motor. Its also nice to turn it off when your hauling something like a trailer for the same reason. Turning the switch off will only affect you at highway speeds, not city driving.
 

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it does two things....1) as said, it prevents the trans from going into OD. With OD off, it's a 3 speed trans. 2) the other thing it does is eliminates the torque converter unlocking from occurring while in gear. It basically makes the torque converter stay locked up.

#2 means you don't get the extra 200-800rpm boost benefit from allowing the torque converter to slip in 2nd and 3rd. This is most noticeable when climbing hills, and you end up going slower at high RPMs in a lower gear.
 

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Discussion Starter #5
it does two things....1) as said, it prevents the trans from going into OD. With OD off, it's a 3 speed trans. 2) the other thing it does is eliminates the torque converter unlocking from occurring while in gear. It basically makes the torque converter stay locked up.

#2 means you don't get the extra 200-800rpm boost benefit from allowing the torque converter to slip in 2nd and 3rd. This is most noticeable when climbing hills, and you end up going slower at high RPMs in a lower gear.
Good explanation! one more question... slip means heat, right? Am I saving the trans anything by keeping the OD off and keeping the torque converter locked? I would suppose its a trade-off between higher rpms and heat.
 

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I drive with OD off most of the time it struggles when going up hill and you hear and feel an in and out vibration

You gain more acceleration by turning the OD off.
 
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