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On 2010 Titan 2wd - 4 vs D Question - Torque Converter Lockup?

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Well thanks to another member here on the forum, I just learned that I am able to move my console shifter right and left to toggle between 4 and D. My questions are:
1. If in 4 instead of D, does that mean that the torque converter lockup does not happen in 4?
2. If lockup does not occur while in 4, does that mean that the transmission will run hotter if towing?
3. Anything else I need to know about selecting 4 while towing?

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9,565 Posts
I'll tell you the way it was explained to me. The TC will lock in both 4th and 5th (nothing lower though). You tow in 4th because in 4th, the input and output shafts are spinning close to or at the same speeds. When the TC locks, there's no slippage at all and not much heat is made. When unlocked, that's where all the heat comes from...especially while pulling a load. 5th gear is too tall for most towing so when the TC unlocks it makes a lot of heat because the input and output shaft speeds are far more in 5th causing much more heat. Too much for the coolers to dissipate fast enough.

So yes, the TC does lock up in 4th but will stay locked longer than if you're using 5th and towing. Basically, 5th is like an OD and works the same way. You'll always run cooler in 4th than in 5th when the TC is unlocked. TOW MODE just hold gears 1 thru 3 longer.

Super Moderator
166,311 Posts
4th gear is 1 to 1, and 5th is a true overdrive:

Transmission type: 5-speed automatic with overdrive
Gear Ratios:
1st: 3.827
2nd: 2.368
3rd: 1.520
4th: 1.000
5th: 0.834
Reverse: 2.613
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