Towing in 4th

Towing a 6x12 Uhaul enclosed tonight from Akron Ohio to Nashville TN and back tomorrow. going down, the trailer will be empty and coming home it'll be loaded with a bedroom suite that is quite heavy. I'll have 3 average size adults in the truck including myself. All Stock suspension. 2014 Tacoma 4x4 4.0 dbl cab w/tow package. Necessary to stay out of OD on the highway during the trip down with the empty trailer? It's mostly flat going through central Ohio. At least through Cincy. I do plan on cruising in 4th on the trip back since weight will be added.

The trailer empty is 1900lbs

Thanks everyone

 

If you can old in 5th gear (OD) for extended stretches then do it, but if you will need to constantly lock and unlock the torque convertor then stick in 4th.

 

lock and unlock as in if it's hunting between 4th and 5th?

 

Yes Tacomamike said it best. If it’s constantly dropping back to 4th from 5th then leave it in 4th. Won’t hurt a thing other than MPG. I tow a lawn trailer and 17ft boat and have no problems keeping up with traffic running 60-70.

 

This is why i lean on the TW people for answers. you guys are great.

Thanks!

 

No. What he means is if the torque converter lockup clutch can't stay locked in 5th. Then drop to forth so the truck will have a perpensity to be in tcc lockup more. Lockup makes it to where there is no "slippage" of the torque converter this keeps temps down

 

I will say I watch my trans temp constantly with my ultra gauge and I will tell you that it will heat up very quickly if left in 5th towing a decent load. In 4th it’s a constant temp most of the drive.

 

What they said about the torque converter. You can tell the torque converter unlocks if you have a rise in rpm that isn’t as drastic as a downshift to 4th. You’ll just kinda see the rpms jump up a few hundred rpm.

 

The torque converter will likely lock and unloading a lot in 5th. This too can cause heat and unnecessary wear. You’ll notice this Lock/unlocking by seeing the rpm jump up slightly. If the unlocking of the converter doesn’t allow enough power, then it will downshift.

Short answer is, better to keep it in 4th.
Yes, you can tow in 5th. But it isn’t fun keeping constant observation on Trans activity.
If you driven your truck very long at all you’ll know what’s best. You can feel it.

 

Just got back to Az from a trip to Utah, put on close to 1,000 miles. Towed a SXS weighing about 1500 lbs along with the trailer, food, bneer etc. Only time I was in OD was on any kind of down grade. On the 15 fwy in Utah the speed limit in parts are 80 mph. Stayed in the right lane and watched as the big rigs drove right past me. Tried to stay around 70.

And yes in 4th the mileage is horrible, but felt it had enough guts to keep me going.

 

Trans temps in 5th locked will be identical to 4th locked. The temps heating up quickly in 5th like you say are because the torque converter lockup clutch isnt locked due to load and accelerator position.

 

Leave it in 4th. Your transmission fluid will be happier to not get cooked at the cost of a couple MPG.

 

If in doubt leave it in 4th. It won't hurt anything to drive it in OD on level terrain, but you can't put it it D and just drive. You have to THINK and drive it like a manual. The key is to anticipate when to downshift and get out of OD. It needs to be done BEFORE the engine starts to strain. If you're in a situation where sustained speeds will be 55 or less stay out of OD. But if you can maintain 60+ without the engine straining OD is OK.

The owners manual is going to say use 4th gear only. And for most people I don't think that is a bad idea. Too many people just put them in gear and drive never thinking that it is entirely possible to manually change gears on an automatic.

 

I'd just put it in 4th and forget about it. The drivetrain will be happier. And if you don't put your foot into it on every hill, and drive more slowly overall, your gas milage won't be terrible.

 

Leave it in 4th. Transmissions are more expensive to have worked on than the wasted gas. You can still do 80 but you will burn gas.

 

Thank you guys for all of that input. Cleared up confusion I had about locking and unlocking. So I made it down to Nashville last night. For the flat stretches and downhill grades, I used OD. Everything else, I was in 4th. I watched the rpms off the bat and figured out when it was unlocking so I avoided that. I used to drive a manual so I get when to downshift. Before it would try to downshift on its own, I dropped it to 4th.

All in all, I played it safe and used 4th the majority of the time. I needed it anyway for the power. 15 mpg and 13 mpg on the tanks. Not horrible at all. Coming home the trailer will be loaded with furniture so I’m sure I’ll be in 4th the whole time!

Thanks again everyone!

 

I tow my trailer in 4th only. Still get pretty good gas mileage, with shifting manually when going over/through the mountain passes in Colorado.

Get's a little annoying when traffic is doing 80+ MPH (speed limits of 75 here) but it's doable and the route I go personally.

 

Did you monitor this with a scangauge? I think the later versions of the A750 transmission has transmission pan and torque converter temp readings. Earlier versions of the transmission only have one of those trans temps available to monitor

 

I monitor my trans temps with my scangauge in my 14' Tacoma. I monitor both the pan and the TC and it's obvious when the TC isn't locked. The TC temps can climb pretty quickly.

 

Pretty sure all years of the 2nd gen taco had the ability for both temps. 12+ saw a change of PID for those temp data streams but it's there.

I use a cheap lil Bluetooth OBD, a free old Android phone, and an acquired version of torque pro if I feel like monitoring trans temps.

Like stated. SUUUUUPER obvious to tell when torque converter is unlocked when the TC temp spikes up.