Can anyone tell me if my 05 will have the torque converter locked if I manually pull it into second gear while pulling a very steep grade at around 30mph???? The owners manual states on page 232 that I should shift to "2nd" gear when climbing long grades and engine braking but then cautions that "when operating in hot weather conditions in 1st or 2nd gear torque converter slip can impose significant additional heat load." So.........is the torque converter locked when operating in a "manual 2nd" or not???
I have gotten a variety of answers on this and nobody seems to agree.

 

If the switch on the end of your shifter is programmed for tow/haul than yes, it should lock up in 2nd if you drop it down to 2. If it's programmed for Overdrive Off than it won't do it.

 

Yes, the TC will lock in manual 2nd and TH should make that lockup occur sooner than no TH. The 2nd gear lockup is a bit different as it is really controlled by throttle position and speed. If you can hold a steady speed up grade without having to go WOT, you should get it to lock under steady speed conditions and keep the trans a lot cooler.

 

I've placed the gear selector in 2nd with the T/H feature enabled and achieved full lock up. It's not like overdrive, which will shift depending on load or throttle position. Second gear will remain locked until you shift, turn off the T/H feature, or slow down to around 20 mph or so. Can't remember the exact speed. Works very well on twisty roads in 30-35mph range.

 

How do I know for sure the torque converter is locked??? I think somewhere I read of a mod you can put on yourself that enables a light to come on that you install on your dash. This would be a great feature. I think I can see the tach drop a couple of hundred RPM's on normal upshifting when starting out on flat ground. I assume the is the torque converter locking and reducing slippage. I'm not sure I will see this when I downshift to 2nd.

 

You should be able to feel it lock. It will feel like another shift and you will loose 300-500 rpms depending on how hard you are pushing it.

 

My early 04' locks in 2nd gear, i dont have the tow/haul programming like the 05's do but mine definatly locks, i drop into second and drive it in second when i am doing under 40 mph the truck runs great and has alot more response in second locked.

 

The torque converter on my 06 locks in 2nd gear at 35 mph. If the truck drops below 35 mph in 2nd gear the torque converter will unlock.

 

Does a 2004.5 / 2005 lock the torque converter in 2nd gear above 35mph? I do not think mine does this with the factory tow / haul button depressed.