[Paxford]

We are looking for the weakest link. Let's start with the axles-

GAWR Front 3160 with 265/65/17 tires

GAWR Rear 3900 with 265/65/17 tires

Total - 7060

I like to compare my 2006 4x4 Sequoia 6200 lb tow capacity to what my prior vehicle, a 2004 Ford Expedition 2 wheel drive with HD tow package, was capable of as reported by the manufacturer.

GAWR Front 3150
GAWR Rear 4128

Total - 7278

Not much difference.

 

[Paxford]

My receiver is Toyota part #51908-oc030. Toyota doesn't give weight ratings for this receiver. I've seen Toyota say they design their receiver to match the tow capacity of the vehicle, which is troubling.

However, Curt makes an aftermarket receiver that looks similar in design, it's part #13440 and rated 6000/10000. It's generally not a good idea to assume anything, but in this case the parts seem very similar so unless there is a specific difference we can point to of concern, then I'd say the Toyota part is probably similar in weight rating. I doubt Toyota would build out a Class III receiver designed to attach to frame then weaken it to a rating of 6200 lbs with weight distribution.

So I don't think the factory receiver is the weak link right now, but it should be looked at closely to confirm.

 

[Paxford]

What about tires? Mine came with-

DUNLOP
GRANDTREK AT20
P 265 /65 R17 110S SL BSW TM

The 110 load index equates to 2,337 lbs per tire x 4 = 9348.

So the stock tires aren't the weak link.

 

[Paxford]

Toyota brought the Sequoia into the US market as a competitor to the Tahoe (and other full size SUVs). It's just supposed to be an affordable/bigger Land Cruiser for the American market. Towing was not a priority in their design. That being said, my money would be on the transmission being the weak link. Perhaps you can find some data to support that. I know they've been using that same basic Aisin transmission for many models since the early 90s and I'm sure it wasn't designed for HD towing.

That may be the case with the 2004 and prior Sequoias with the A340 transmission used on 2004 and prior, but 2005-2009 used the A750 transmission. 2nd gen Sequoia's with the A750 and 5.7L can tow up to 10,000 while 2nd gen's with the 4.6L are still rated in the low 6000's. I know very little about these transmissions, just going off specs I looked up on wikipedia.

That suggests the motor is a potential limiting factor. A bit of a shock considering the 4.10 gearing.

I'm also wondering about the radiator and transmission cooler, whether they are upgraded to get to that 10K tow rating on the 2nd gen, and also whether we can upgrade them on our first gen's.

 

[Paxford]

Sure, except I always compare back to a Ford Expedition which is rated for 8950 lbs. In the braking test linked below the Sequoia stopped better than the Expedition. The Sequoia is the best of the bunch when it comes to braking.

https://www.motortrend.com/news/chevrolet-tahoe-2/

So I don't think the brakes are the limiting factor.

 

[Paxford]

JJ805, I agree the motor is the limiting factor. I pulled 6k with an 03' Expedition with the 5.4L 16V and 350 lb/ft of torque. Your 05' has the same displacement of 5.4L, but 24v and 365 lb/ft of torque. The Expo did great on hills but honestly it wasn't as stable a towing platform as the Sequoia. And the Expo transmission was junk at 103k miles. I think it may be the rear IFS in the Expedition which makes it much more squirrely. On the flats I would take a Sequoia over an Expo every time. But not at altitude.

I pulled around 4k (loaded) with the Sequoia for many years and didn't have power issues. I just stepped that up to about 5200k (loaded) and pulled steep long grades in the Rockies, the Sierras and Tushar range in Utah, often going to ~11,000 feet. The power concerns are real. The motor will pull it, but it will also get hot. The needle on the dash never got close to overheating, but the scanguage doesn't lie. The transmission never skipped a beat, but as motor temps rise the transmission has a harder time keeping cool. If I had an unmaintained vehicle, or earlier model year with less power, or pulled more weight then I could see the motor having issues.

Right now my plan is to go 70/30 mix in the radiator and keep it maintained to a fault. She's got 139k on her so a new radiator might be in order. The thermostat and water pump are fine. A larger transmission cooler may also be in order. As for increasing torque I am open to ideas, I haven't found any reliable cost effective solutions. Ultimately there may be no replacement for displacement.

 

[Paxford]

Awesome! I drive the same roads and deal with the same sluggishness and downshifts. With the injectors did mileage also take a big hit when not towing? Throwing any codes?

FYI there are two clean low mileage 4x4 1st gens for sale in SoCal right now, in white and blue.


Sent from my iPhone using Tapatalk

 

[Paxford]

Just spoke with Keith, great talk we had! Keith knows his craft very well and understood what I was trying to accomplish. More power and no CEL or mods that could be a red flag at the CA smog check. I think the trouble some on this thread are having with finding BA Muffler products is that the website to find them is dirty deeds industries ...

12 Hole Fuel Injectors - Performance Without Drone

PLEASE CALL FOR AVAILABILITY AS THESE COULD BE SUBJECT TO BACK ORDER 12 hole 250cc, 270cc and 330cc injectors are an awesome upgrade for your 2000-2006 Toyota Tundra. The 12 hole injectors turns gasoline into a mist vs stock 4 hole injectors which turns the gasoline into a stream. The…

dirtydeedsindustries.com

I'm buying set of 270 cc injectors today for $300 and doing a self install. At 140k miles it likely needs new injectors anyways. JJ I couldn't find your install write-up, I searched BA Mufflers, BAMufflers, and sorted by time and scrolled through the July 2018 threads, nothing seemed on point.

Some tips I picked up from Keith, the ecu retards the timing in blocks of 4 as soon as it senses knock. It can easily go negative timing if not watched closely. To avoid knock keep the RPM's up and run better fuel. Reminds me of oh so many times on the I15 where I swear the motor is losing power ... because it is! Also keep the motor in closed loop as much as possible or your dumping fuel. Also mentioned were throttle body coolant bypass and the airbox mod (2 inch recommended) for free power at minimal cost. There are downsides though.

 

[Paxford]

btw I've hijacked my own thread