Towing In "D" versus "4th" Gear w/Tow Mode - Page 2

Boots · 05-23-2007, 07:23 AM

I can't beleave some of you Folks are towing boats and such at over 80 MPH. Isn't that like really being irresponsible, unsafe and putting the rest of us in harms way? I got to admit though watching pickups towing trailers around an Oval race track would be a real riot. (No electric brakes allowed)

Triple S · 05-23-2007, 11:48 AM

My complete load is just under 5,000 pounds, I always have the Tow Mode activated when the trailer is attached, I like the higher shift points. When I leave the house and go to Watkins Glen the distance is about 80 miles.

Almost a perfect half of that is NYS Thruway, and that section is rather flat, I'm in D during that entire portion, turning 2,000 rpms at about 72 mph. I can clearly see the torque converter has locked up because the revs are right where they should be and my tranny temp never gets up to 1/2 way.

The second half is a very good county road that for the most part runs straight although it does have some good hills there are not a lot. I also run in D in this section at about 62 mph, and just like before, the torque converter has locked up and my tranny temp never gets up to 1/2 way. Once I get closer to Watkins Glen I have several monster hills to deal with, only then do I drop back to 4th.

I do also perform lots of downshifts and holding lower gears downhill when I'm dealing with these hills as it helps out on the brakes.

And, here is an interesting FYI- I pulled a 12.6 mpg during this last tow, that's about the same gas mileage I got day-to-day driving in the winter when my fuel economy always goes down.

I LUV MY TITAN!

Learjet · 05-24-2007, 08:34 AM

Quote:

Originally Posted by Boots

I can't beleave some of you Folks are towing boats and such at over 80 MPH. Isn't that like really being irresponsible, unsafe and putting the rest of us in harms way? I got to admit though watching pickups towing trailers around an Oval race track would be a real riot. (No electric brakes allowed)

yep, some folks think the laws don't apply to them. Plus, if they kill some innocent person, they can just say sorry.

Triple S · 05-24-2007, 09:05 AM

Oddly enough, the worst situation I have ever had towing was caused by a cop. I was towing along minding my own business staying back from traffic doing my 70 to 72 mph when I noticed a cop car coming up fast in the left lane, and I mean fast. No siren, no lights flashing, just seriously fast. The car flies past me, brake lights come on, car drops right down in front of me and there is no way I'm diving onto the brakes and loose the trailer and car. I resolved myself to punting into the backend of the cop car, I figured my 10,000 pounds would get his attention. Just before impact he swerves off onto an exit. The dolt passed me just to take the exit in front of me, as opposed to slowing down and taking the exit after I had driven past it. Even people who should know better forget vehicles towing do not handle or perform like they do unladen.

BubbaGoose · 05-30-2007, 05:51 PM

Sounds like a Houston Kop...

radiokid · 06-04-2007, 01:40 PM

Well here is some real world experience I just gained last week. I tow a 6600# load and traveled from the SF Bay area to Redding for a week at Shasta. Its around 244 miles from sea level to 1067ft up the central valley. The climb is so gradual that I left it in 5th and on crusie control. The 07 really has noticeably more power for towing with the BT package. The tranny only downshifted a half dozen times and the gauges never budged at up tp 90 deg F at 58 mph. Gas mileage averaged almost 12 over the 4 hour pull, so no complaints here. Only that the gas dock was $5.50/gal

ZeroPt99 · 06-05-2007, 09:49 AM

I'd like to add a rookie question to the mix.

Can someone explain the torque converter locking/unlocking concept to me?

I don't really know what you guys are talking about, and I'd rather ask than just nod and smile.

**loufish** · 06-05-2007, 08:44 PM

Quote:

Can someone explain the torque converter locking/unlocking concept to me?

The torque converter is the link between the engine and transmission. It's also a fluid coupler, that is it slips enough to allow the engine to idle but the truck stays put. On top of that it uses turbine type vanes inside to create a small amount of torque multipication.

As the engine speed increases the converter slips less causing the veh to move. At road speed there's always some slip left, causing less milage along with some heat.

New vehs have the ability to use fluid and internal clutchs to completely lock up the converter just like a manual trans clutch does. this picks up milage and reduces trans heat.
Now...the reality is that the vehs computer can apply any amount of lock up it's programmed to do, so the T/C recieves a command for how much it should lock up, and when towing you want that to happen at lower rpm to keep from heating up the trans, but sometimes the factory programing doesn't do this when we want it to...

ZeroPt99 · 06-06-2007, 08:06 AM

Quote:

Originally Posted by loufish

The torque converter is the link between the engine and transmission. It's also a fluid coupler, that is it slips enough to allow the engine to idle but the truck stays put. On top of that it uses turbine type vanes inside to create a small amount of torque multipication.

As the engine speed increases the converter slips less causing the veh to move. At road speed there's always some slip left, causing less milage along with some heat.

New vehs have the ability to use fluid and internal clutchs to completely lock up the converter just like a manual trans clutch does. this picks up milage and reduces trans heat.
Now...the reality is that the vehs computer can apply any amount of lock up it's programmed to do, so the T/C recieves a command for how much it should lock up, and when towing you want that to happen at lower rpm to keep from heating up the trans, but sometimes the factory programing doesn't do this when we want it to...

That makes sense, so then how can you guys tell when the torque converter is locked versus unlocked at freeway speed when towing? What's the tell-tale sign that it's not staying locked?

**loufish** · 06-06-2007, 08:30 PM

Quote:

That makes sense, so then how can you guys tell when the torque converter is locked versus unlocked at freeway speed when towing? What's the tell-tale sign that it's not staying locked?

Start by keeping an eye on the tach, w/ tow package and stock size tires you should be turning 2000 rpm at 70 mph w/locked t/c, add another 350-400 when not locked.
If you are going down the hiway, and slowly increase throttle, when the t/c unlocks it will feel like you droped a gear.
You have to start getting it "tune" with your truck...