S vs D and Tow/Haul Switch

4.6L? What are you towing?

 

I have a few questions. I am getting a 2020 Tundra 4x4 Ext cab. I will be towing a 23’ Airstream Serenity. Here are my questions.

1) how many miles should I put on the truck before towing?
2) should I get a hitch with the combo wdh and sway bar or separate the two? What brand?
3) should I get a transmission cooler?
4) what should I get to check the transmission temperature?
5) Should I add an auxiliary gas tank in the bed? Currently has a 38 gallon tank.
6) should I add airbag suspension to the truck?

I haven’t towed since the 70’s to speak of and have never owned a TT. The trailer weighs about 5000 lbs dry. I may get a four wheeler and put it in the bed. I live in AZ and will be living on the road full time. All my towing will be in the western states. Should I upgrade The trailer tires from 14” to 15 inch and if so, what all is involved in doing that? I know I’m asking a lot of questions, but I need all the help I can get according to everyone that knows me.

 

It has the Ted off road package also.

 

TRD

 

Hi, I quote you also so I can see your questions 1 by 1. I am sure you will get lots of advice, but since my situation similar to your’s (recent upgrade to Tundra from Tacoma and new purchase AS Bambi 20’; all 3 weeks back). I will share my learnings and feedback after firt 3 day trip. Per your numbered items:
1) The Tundra owner’s manual states 500 miles. I bought Tundra on a Friday and worked in 3 days driving to reach 400+ to add to the 115 miles to go get the AS on following Tuesday.
2) I read multiple forums on the matter and also listed to the sales people and then read the hitch company infp. I went with a Blue Ox SwayPro weight distribution hitch. It was a bit pricy at dealer at $750 but I think you can get on Amazon at $100 or so less. The tension bars come on 550lb, 750 lb, 1000 lb, 1500 lb, ...My AS stated dry weight is 3962 lb. Be sure to look at the label inside the screen door or the label on the outside on street side to see final weight numbers as opposed to whet is in brochure. Stated tongue weight is 540 lb. Given that number is close to 550 lb tension bar and considering I might have extra load weigh in TT up front we went with 750 lb tension bars (I also contacted Blue Ox and they agreed). If you get Blue Ox you need to wrap chains at certain number of links down (starting with 9 links as initial set up) in latch brackets and rotate to locked position. The BO book, and in my case the dealer set up guy, did not give clear instruction and hooking was difficult. You must couple the trailer and hitch ball and latch the couple. Then you jack trailer up a lot, it will also jack up back of truck. What this does is causes the trailer frame to slope back and become more parallel with the tension bars which are hooked on the hitch head. With that it becomes easy to then use the 10th link from top to hook into the latch if you need to do so for better weight distribution. Worked out better for me when I moved from link 9 to link 10.
3) Big debates on transmission cooler. Since you ask maybe you have been reading posts. The Tundra eBrochure and the “sticker” on my 2020 SR5 Upgrade Package, TRD OR with Tow Package claims it has transmission cooler, but other folks have educated me that this is not truely a transmission cooler like the mini-cooler I could see in front of the radiator on my Tacoma. Some folks have said if you use TOW/HAUL switch as you are supposed to and S4 gear then you will get the cooling needed. IDK. I used T/H and S4 and even S5 (given my trailer weight is less tha 50% max allowed) and even in S5 when on flatter terrain did not sense any transmission cycling up and down and cruized at 60 mph and at time found myself at 65 mph.
4) Someone suggested ScanGauge SG2 Ultra and I just purchased one today on Amazon. It plugs directly into your truck diagnostic connection port below steering wheel above brake. You can monito transmission temperature. I will try this to determine if temperature become too high before trying to have after market transmission cooler installed.
5) 38 gallons seems quite sufficient to me. I have lived in 8 states, 5 out west, and worked in just about every western state while in USAF (and used large Dodge double cab PowerWagon then). Always seemed to be enough gas stations around. Just don’t go into missle of Nevada somewhere on half tank, park the trailer, and do a lot of truck treking. 5 gallon jerry can of gas should at least get your non-trailered truck to a nearby gas station to fill up if need be. Another thing to keep in mind is that your truck weight information (on the labels and in the owner’s manual relative to your truck code which is on the door label), not in the brochure) does include a full tank of gas 38 gal at 6lb/gal. That may be one of reasons, along with any extra things like side steps and tow package, your payload is not actually 1500 lbs. My truck payload, per door label is 1320 lb. if your tonue weight is sy 600 lb, then that and any extra fuel tank will eat into whatever extra weight capacity you have for carrying stuff.
6) If you use weight distribution hitch like Blue Ox and you do not use tension bars that are too heavily rated, ie don’t use 1000 or 1500 lbs, then I see no reason for airbags. As noted, my trailer dry weigh is 3962 lb. I had full fresh water and hot water tanks (27 gal and 6 gal at 8.3 lb/gal = 274 lb). plus I had about 50 lbs of stuff. So almost 4300 lb. I went to CAT scales multple times to get truck axle weights and then truck and trailer axle weights at Blue Ox weight distribution using 8 and 9 links. Even 9 links was a bit light at distributing weight back down on truck front steer wheels, but only by about 60 lb. But wheel center to base fender distance was same as before loading with trailer. I need togo backnow that I figured out how to chain the tension bars properly and measure axle weights using link 10 on BO WD hitch. But I suspect it is about perfect based on tape measure measurements of wheel center to base fender pre and post trailer loading and measure of street to base frame front and back of trailer. I do not have airbags and my own driving and towing was realatively smooth.

I have no comment on trailer tires. I saw a tread on Tundra truck tires and some have changed those out. I won’t do so until such time the ones I have wear out. But I doread that pushing the tire pressure up towards the max rating may be best. For now I run 35 in front and 37 in rear, but may bump up to 38 and 40 when I tow again in a week or two.

I’m sure you’ll gets lots of varying decisons. I go good advice here, evaluated, made some choices, experimented and all seems to be smoothing out.

Good luck.

 

I'm towing a 28 '10k travel...a lot....cruise dont like towing..I've had it disengage on its own i thought it was breaking down...just seeing all this talk about such low gears seems crazy...my trans downshifts and grabs as needed in D and I'm getting 6.5 mpg...i can't imagine having it scream for so long in low gears...what do u get in s4 n 5...like 3mpg....I'll be hitting every gas station...I'm kinda stuck in d....I've slapped low gears for downshifting declines

 

MikenMike, when I said cruize at 60 mph, that was not to imply that I used cruize control all the time, but just “cruizing along”. But there were some times when I used cruize control on open straight road for couple minutes to rest a very aching right knee. I drove using Tow/Haul switch engaged and mostly used S5 where RPM seemed to stay around 1800. I think when I am in D and not pulling a trailer it tends to run 1500-1600 anyway at 60 mph. But now you reference it I want to recheck. Topped off my 38 gal tank (could see fuel at top of inlet) at home. Pulled trailer to camp site which was 161 miles away. Unhooked and set up. Later that evening drove to and from seaside restaurant, round trip 22 mi. Next morning drove down to North Myrtle Beach to see the old gas station I worked at 51 years ago this summer before starting senior year of HS. That was 18 miles. Drove back up Hwy 2 miles and fuel at BP and topped off tank as before. All totaled 203 miles. 161 miles pulling trailer, 42 miles without trailer. 16.568 gal to top off tank again. Thus, 12.25 mpg. Not bad. But again, my trailer weight is only 4300 lb and I was driving on relatively flat coast plain. Never used D when pulling the trailer.

 

You definitely won’t do any worse than 6.5 mpg holding lower gears. Have you actually weighed the trailer loaded and ready to tow? No way I would want to tow a 10k lb travel trailer with any half ton if you’re towing frequently or in hills/mountains.
IMO you have too much trailer or not enough truck.

 

Don't do that. Bad for the fuel system and a pain to repair if you damage it. The little stickers and such that tell you not to top off your tank after the nozzle shuts off are not a nanny sticker, they are a warning that you will break stuff.

 

Thanks for that insight. Didn’t read the fine print.

 

It's like 9k....I can't wait for the 1 tundra..but I'm content..that's without air

 

1 Ton-dra? I like that.

 

Looks good. Well done.

 

How are they not cashing in on the one tundra...they would kill the market...but I had no idea I should be in 5s?..not D?....the tow button i use...seems to dump some more fuel but I was wondering where overdrive is....or if 6th is considered that...on my 1st gen it's on the shifter

 

5 and 6 are both overdrive. 4 is 1:1.

 

So I can haul at 70 in 4?...this can't be right

 

Yes you can. Pretty sure you’ll be a bit under 3,000 RPM. Truck would much rather work there than 1500 RPM in 6.

 

So if I'm in s4 I still need to put it in d when I'm off the highway...still need to work lower gears in s?

 

Wow...but it would be nice to know for sure what gear it's in while towing in D

 

Putting the truck into S mode purely limits the highest gear the truck will use. It will run all the lower gears as normal, but it won't shift beyond the gear you select in S mode.

 

There is no rule book but when the truck isn’t working hard, I shift to S5, S6 or just put it in D depending on how much weight I’m moving. Given your trailer weight, I probably wouldn’t go higher than S5. If you’re stop and go city driving I would keep it in S4 and only use S5 for longer flat stretches at sustained speed.

 

Thanks for the insight the ice to know it just limits but works lowers

 

+1. I tow a travel trailer which is about 6000# when loaded up and keep it in S4 mostly, I’ll give it S5 on the highway when flat. On bigger hills or in the mountains I’ll drop to S3 to keep the revs in the meat of the powerband. Truck tows really well when you pay attention, look ahead and mind your gear selection just a bit. Cheers.

 

I often tow a motorcycle trailer (now), but I'd like to buy a light (5000lb or so) Travel trailer.

 

Should be fine. Would be smart to add a trans cooler and anti-sway bar if you’ll be towing in the mountains, long distance, or frequently. Even towing a trailer that light can be brutal in a strong headwind or crosswind because of the high profile.

 

Anti-sway I expected...probably not many mountains. Have the Tekonsha installed, any thoughts about tow/haul button?

 

My understanding is it’s not something you can add. You’d have to look at an aftermarket tune such as bullydog.

 

I agree with this not sure why you would be in s4 all.the time towing.

 

To keep the torque converter locked to keep the transmission temperature down.

 

Temp down running at higher rpms? The way I read it in manual is that for down hill control not on flats