Towing a TT while not quite broken in?

[Learjet]

Originally Posted by Yahooligan

The truck purrs along in 5th gear at 55mph/1500rpm quite nicely on level ground, trans temp gauge doesn't move.

I would tow in 4th per the owners manual page 9-34. You are bogging the engine down at that RPM with the wind resistance of the TT at highway speeds. Your converter is probably unlocking on every overpass and causing unnecessary wear on the transmission. The general consensus is: tow heavy loads or high profile loads in 4th (non-overdrive)

I towed a similar size travel trailer over 4000 miles in 4th and my tramisson temp never moves, converter stay locked unless it is time for 3rd gear up a big hill.

my 2 cents

[Yahooligan]

Originally Posted by Learjet

I would tow in 4th per the owners manual page 9-34. You are bogging the engine down at that RPM with the wind resistance of the TT at highway speeds. Your converter is probably unlocking on every overpass and causing unnecessary wear on the transmission. The general consensus is: tow heavy loads or high profile loads in 4th (non-overdrive)

I towed a similar size travel trailer over 4000 miles in 4th and my tramisson temp never moves, converter stay locked unless it is time for 3rd gear up a big hill.

my 2 cents

I'll look in my manual again, but I didn't see anyting that said not to drive in 5th/OD. Also, as I said, running in 5th/OD on level ground was fine. T/C was locked, RPMs were steady, it wasn't hunting, trans temp gauge didn't move. There was no bogging down going on, in 5th if there is the slightest bit of need for more than minimal throttle it will unlock the T/C and/or downshift. Heat is the killer and neither the trans nor the engine had any issues. Overpasses in the middle of the desert are pretty rare.

Thanks for the advice, I plan on keeping this truck for a long time. Not new to towing, just new to towing with the Titan and thought I'd share how it went so far.

Definitely not the same as towing with the Cummins Ram I had. With that you set the cruise at 65-70 in 5th gear and only change speed when you stop for fuel. The Titan is more enjoyable to drive, I just wish it got the same 17mpg while towing as the Ram. Oh well, unleaded is cheaper than diesel right now so it may not make that much if a difference.

[Retired Dude]

Originally Posted by Learjet

Your converter is probably unlocking on every overpass and causing unnecessary wear on the transmission. The general consensus is: tow heavy loads or high profile loads in 4th (non-overdrive)

What does an overpass have to do with the transmission? An overpass will freeze before the road surface does, but that is due to there not being any earth below it to provide any warmth.

Are you thinking that there would be a lot more wind at an overpass?

I haven't towed any heavy trailers with my Titan, yet, but I do have a lot of experience towing a race car with various other trucks. I never noticed anything unusual with the transmission while going over an overpass.

[Learjet]

Originally Posted by Retired Dude

What does an overpass have to do with the transmission? An overpass will freeze before the road surface does, but that is due to there not being any earth below it to provide any warmth.

Are you thinking that there would be a lot more wind at an overpass?

I haven't towed any heavy trailers with my Titan, yet, but I do have a lot of experience towing a race car with various other trucks. I never noticed anything unusual with the transmission while going over an overpass.

I was using overpass as an example of a common hill or short grade.

[Learjet]

Originally Posted by Yahooligan

There was no bogging down going on, in 5th if there is the slightest bit of need for more than minimal throttle it will unlock the T/C and/or downshift. Heat is the killer and neither the trans nor the engine had any issues. Overpasses in the middle of the desert are pretty rare.

.

Think of it this way... you need "x" amount of power (hp) in your situation. You can achieve that by.. power per stroke x number of strokes (RPM)= power(HP)

What do you think your power per stroke is at 1500 rpm? It is high.
That is a lot of cylinder pressure, crank pressure, connecting rod pressure etc. You are not doing any favors to your engine in this case by running in 5th when 4th will increase RPM just enough to put you in a better power band and decrease the power per stroke by spreading it out over more strokes.

What you just said about any minimal throttle increase will unlock the torque converter proves that you are on the design edge of what Nissan wants with that engine.

You also may reduce the cooling at 1500 rpm by lowering the radiator fan speed, water pump speed, transmission fluid pump speed and reduce alternator output.

Hope this info helps.

[Retired Dude]

Originally Posted by Learjet

I was using overpass as an example of a common hill or short grade.

Okay, thanks. I just couldn't figure out what an overpass had to do with it.

[Yahooligan]

Originally Posted by Learjet

Think of it this way... you need "x" amount of power (hp) in your situation. You can achieve that by.. power per stroke x number of strokes (RPM)= power(HP)

What do you think your power per stroke is at 1500 rpm? It is high.
That is a lot of cylinder pressure, crank pressure, connecting rod pressure etc. You are not doing any favors to your engine in this case by running in 5th when 4th will increase RPM just enough to put you in a better power band and decrease the power per stroke by spreading it out over more strokes.

What you just said about any minimal throttle increase will unlock the torque converter proves that you are on the design edge of what Nissan wants with that engine.

You also may reduce the cooling at 1500 rpm by lowering the radiator fan speed, water pump speed, transmission fluid pump speed and reduce alternator output.

Hope this info helps.

I understand what you're saying, but I think you're trying to apply that to all loads on the engine and it's not something that can be used universally.

Using a manual transmission as an example since it doesn't downshift for you, running in 5th/OD @ 50+% throttle @ 1500rpm is like you say above, it's lugging the engine trying to work hard outside of its ideal/most efficient powerband.

That is very different from running in 5th/OD @ 15% throttle @ 1500rpm, where the load on the engine is light and it's not working hard.

The fact that the truck is able to cruise in 5th with the T/C locked while towing shows what load is on the engine and transmission, relatively minimal. That was my point in what I said above. If the power demand was high then the T/C would not lock in 5th. I know the sound of my engine under various loads and RPMs, it was not straining.

Don't get me wrong, I'm not trying to say towing in 5th gear is the thing to do all the time. I certainly don't do it all the time, but there are conditions where towing in 5th can be done without issue or adverse effects. The ears and gauges don't lie. However, now that I'm fully broken-in for trailering, I'm not going to limit myself to 50-55 on the flats. Hills are another story and it's quite obvious where the truck is most comfortable speed-wise heading up hills.

I do think it was rather impressive (to me, anyway, maybe not to others ) that I was able to drive from Carlsbad to Blythe, 210 miles, on a single tank. In fact, the truck only took 22 gallons when I filled up. 9.5MPG for a largely-uphill drive (Up I-15, through Hemet and over the hills to I-10, up to Chiriaco Summit <1775ft elevation change in 26 miles> and then over to Blythe) was pretty good in my book.

This trip has pretty much solidified our thoughts on buying a TT of our own, we definitely want one! I'm also pretty sold on Keystone trailers, such as the Outback 29BHS.

Happy holidays and Merry Christmas!

[Aquaholic]

I was told to wait 1500 miles to tow. Just drive around the block a few hundred times.

[Yahooligan]

Originally Posted by Aquaholic

I was told to wait 1500 miles to tow. Just drive around the block a few hundred times.

I managed to reach about 1400 or so before I left, I'm at 2000 now.

[Learjet]

I have gotten 10 mpg towing my TT in 4th. The lowest was @ 9 mpg in 4th. This is 60-65 mph on the interstate and flat ground. The most RPM I will see is @ 2200 rpm.

[AgTitan06]

Originally Posted by Aquaholic

I was told to wait 1500 miles to tow. Just drive around the block a few hundred times.

Manual doesn't say this anywhere. That's a lot of miles to wait to tow if you really need to.

[SKEET]

Any other manufactures require that you not get over 50 mph for 500 miles while towing?50 mph on the interstate is a crawl.Would a 2k pound boat require the same break in or is that enough wait to even worry about.

[Yahooligan]

Originally Posted by AgTitan06

Manual doesn't say this anywhere. That's a lot of miles to wait to tow if you really need to.

The only things I see in the manual are:

Don't tow within the first 500 miles.

Don't go over 50mph within the first 500 towing miles.

Other than that, I guess it's fair game!

[SKEET]

Originally Posted by SKEET

Any other manufactures require that you not get over 50 mph for 500 miles while towing?50 mph on the interstate is a crawl.Would a 2k pound boat require the same break in or is that enough wait to even worry about.

Anybody???????