Sienna Gen-II Towing Capacity. (2004-2010)

[tcp]

We just returned from another 2 weeks of camping through the Canadian Rockies with the Sienna and our F-18Bantam. 3600lb trailer and a loaded up Sienna did fine through all the roads and mountain passes. Calgary-Edmonton-Jasper-Kamloops-Kelowna-Revelstoke-Golden-Radium-Banff and back to Calgary. 2800kms covered and the sienna was a champ. blew past a bunch of RVs struggling up Sinclair pass out of Radium at 80km/hr without issue. Roger's pass, not even a concern.

I logged speed, engine rpm, water temperature, throttle position and engine load throughout the trip on my OBD logger. never broke 4000rpm. water temps stayed at 180-195F throughout except for a slow windy section up to Kicking Horse Resort in golden where we got to about 205F. throttle position at <70% throughout and engine load never broke 80%.

I just swapped out 5liters of transmission fluid tonight and the old stuff looks a tiny bit darker than the new, but smells and feels exactly the same. Great tow vehicle.

[briank]

Just to add my 2 cents, one could add an oil filter heatsink with thermal paste which may be almost as effective as the oil cooler in the tow package. Google "oil filter heatsink"

[brian_bp]

... one could add an oil filter heatsink with thermal paste which may be almost as effective as the oil cooler in the tow package...

I understand the idea, and I suppose it couldn't hurt, but it would take a lot to convince me that some fins on the filter housing would have any substantial effect, let alone approach the effectiveness of the factory oil-to-coolant heat exchanger.

[cmarks]

Can anyone offer thoughts as to what gear(s) they typically use when towing? We just got a new(used) pop-up for our family and it has an unloaded weight of ~2400lbs.

Being new to towing with my 2006 Sienna, I do not want to neglect or abuse the automatic transmission, but want to be a good steward by finding out what it best on how to use it properly from experienced folks.

Also, can someone expand on the necessity of a Weight Distribution? It seems that most people here have them, but do we know why? Why is it good for the Sienna?

Thanks in advance for your thoughts.

[brian_bp]

Can anyone offer thoughts as to what gear(s) they typically use when towing? We just got a new(used) pop-up for our family and it has an unloaded weight of ~2400lbs.

I generally leave it in Drive.

The Sienna has no special "tow/haul" mode, so the shifting may not be quite as desired in some loaded conditions, so it may be prudent to manually take some action:

• If the transmission "hunts" - shifting often between two gears as if uncertain which one is appropriate - this can be stopped by manually selecting the lower of the two gears. I have rarely noticed this, but it can happen while climbing steep extended grades, or even in more moderate condition if travelling right around the appropriate speed to change gears.
• The Sienna's "grade logic" downshifts for engine braking on descents, but occasionally it may not downshift enough for the conditions (to avoid riding the brake to keep speed down as desired), so it makes sense to downshift to a low enough gear. I have only found this on very steep and slow grades.
• The only perhaps "abusive" condition would be running with the torque converter not locked, instead of one gear lower and locked up. This would be a reason to shift down to the lower gear.
  

In practice, even while towing in Drive 5th gear is rarely used except on flat or gradually descending roads; it is an automatic and generally downshifts as appropriate.

This is a common topic, so I suggest looking for previous discussions in this forum before adding further to this topic, which is about capacity.

[brian_bp]

Also, can someone expand on the necessity of a Weight Distribution?

From the viewpoint of capacity, there are two considerations for use of a weight-distribution system.

The hitch weight limit in weight-carrying mode (no WD system) is 350 lb; any higher, and WD is required. This may be a structural limit, or perhaps set by Toyota to make it less likely that people exceed the other relevant limit...

... which is rear axle load. A WD system exists to remove load from the tug's rear axle, transferring it to the tug's front axle and to the trailer axle, in a proportion determined by relative inter-axle distances. The Sienna's Gross Axle Weight Rating or GAWR (for both front and rear) is 1290 kg (2838 lb), as shown in the manual and on the certification label at the driver's door. If hitching the trailer while carrying the passenger and cargo that are also along for the trip would exceed that limit, a WD system can reduce the load to an acceptable level... but so can shifting the load in the trailer and van in some cases.

Our travel trailer weighs about 2400 lb empty and we tow it at about 3000 lb loaded. The tongue weight is within the weight-carrying limit (about 305 lb typically) and with it hitched our rear axle load is no more than the GAWR. We do not use a WD system

Weight distribution system use is often discussed and can be controversial. For additional discussion, I suggest searching this forum for existing topics, and if appropriate starting a new one, rather than adding further to this topic... which is supposed to be about towing capacity.

[jeburns55]

According to Toyota.com, the 2011 Sienna XLE (FWD) has the towing prep as "Standard". Would that be true of XLE models in 2008? Our 2008 Sienna XLE did not list the Towing Prep as an option on the window sticker from the factory; but the last time I had the van serviced at our Toyota dealer, they charged me to replace an "oiler cooler line".

[jeburns55]

Got my answer from Toyota. So I don't have the towing package...but why is it that they charged me to change the oil cooler line? See response:
Subject

Towing Capacity for 2008 Sienna XLE



Discussion Thread

Response (ATia)
05/23/2011 12:49 PM

Dear Mr. Burns,

Thank you for contacting Toyota Motor Sales, U.S.A., Inc.

We appreciate the opportunity to address your inquiry.

We have researched your provided Vehicle Identification Number (VIN), 5TDZK22C88S117421, and can advise that this 2008 Toyota Sienna XLE is not equipped with the Towing Prep Package. You are correct that for the 2011 model year, the Sienna XLE receives the Towing Prep Option as standard equipment; however, the sales brochure for the 2008 Sienna, located at http://www.toyotacertified.com/ebrochures/08_sienna.pdf, lists the Towing Prep Package as optional for all 2008 Siennas. Referring to the specific list of factory options for the Sienna in question, it was not built with this factory option. As such, the maximum towing capacity for this vehicle will be 1,200 lbs. This recommendation is made in section 6-1 of the vehicle's owner's manual, titled "Specifications". We apologize for any confusion regarding the equipment level of your mother-in-law's vehicle.

If we can be of further assistance, please feel free to contact us at http://www.toyota.com/help/contactus.html.

Sincerely,

Alex Tiampo
Toyota Customer Experience

[brian_bp]

So I don't have the towing package...but why is it that they charged me to change the oil cooler line?

I don't know what happened in this case, but if it were my vehicle I would want a much more specific description. Automatic transmission fluid (ATF) is also casually (and correctly) called "oil", and there is a transmission fluid cooler. There's also a hose carrying engine oil for the VVT system which is not associated with a cooler, but is still and oil line and has needed replacement in many Siennas with the 2GR-FE engine (2007-current).

[g35zuniga]

I have a 2006 AWD limited, according to the brochure and some discussions here, I have the tow package as standard equipment. Based on the first pictures however my sienna doesn't look anything like what is shown. Do i for sure have the package? I got my hitch installed and just want to be safe.

[brian_bp]

I have a 2006 AWD limited, according to the brochure and some discussions here, I have the tow package as standard equipment. Based on the first pictures however my sienna doesn't look anything like what is shown. Do i for sure have the package?

Specifically what pictures are we talking about? The very first post of this thread has photos showing identifying characteristics of a Sienna with the towing preparation package for a Sienna with the 2GR-FE (3.5L) engine, which is used starting in 2007. No 2006 Sienna engine - with or without the towing package - will look quite like this because a 2006 has the entirely different 3MZ-FE (3.3L) engine. The 2006 towing preparation package does not involve engine changes.

[g35zuniga]

Well basically how do I tell I have the tow package for 2006?

[Greg Johnson]

I am looking at buying a 08 or newer Sienna and have read the tow prep pkg and towing posts. Seems most dealers / sales people don't know the tow prep pkg was an option beginning on 08 vs std (per Sienna brochures)in 04-07.

SO, my question: What do I look for on the van to confirm that the vehicle infact had the oil cooler for the tow prep since this is the key thing to look for. If you happen to have a picture that would be great. If not tell me where to look in the engine compartment / on the engine to confirm it has the oil cooler.

[datsa noydb]

Well basically how do I tell I have the tow package for 2006?

Your '06 has the 3.3L engine, and, as far as I know, all the Siennas with the 3.3L engine were rated to tow 3500 pounds.

SO, my question: What do I look for on the van to confirm that the vehicle infact had the oil cooler for the tow prep since this is the key thing to look for.

I don't know how visible it is, but, as I understand it, the "towing prep package" for the 3.5L engine is not a transmission cooler, it is an engine oil cooler, and can NOT be retro-fitted after the vehicle is made. I have no experience with the 3.5L engine, so have no idea just how much extra cooling it might need while towing.

.

[brian_bp]

I am looking at buying a 08 or newer Sienna and have read the tow prep pkg and towing posts. Seems most dealers / sales people don't know the tow prep pkg was an option beginning on 08 vs std (per Sienna brochures)in 04-07.

SO, my question: What do I look for on the van to confirm that the vehicle infact had the oil cooler for the tow prep since this is the key thing to look for. If you happen to have a picture that would be great. If not tell me where to look in the engine compartment / on the engine to confirm it has the oil cooler.

Here we have the problem of a thread with over 100 posts... you need to read through it (not just the last page) to find information which has already been presented. The very first post was edited to include some of these pictures, where where originally presented through the discussion, such as in post #30, post #46, and post #90.