Towing with Sienna/Rav4/Highlander?

[Carol H]

Originally Posted by Mike Magee

Can we discuss whether there's a way for a layman to know when the torque converter is locked? I've been under the assumption that I could tell by the behavior of engine RPMs, but maybe I'm wrong.

Where is the LIKE button?

[rabbit]

More semantic hunting than gear hunting here. What's all the stir over the word "locked"? I've never had one of those +\- shifters and only one automatic trans in 40 yrs of driving. Seems to me lower gears are always available whatever the chosen gear and higher are not. Fifth gear can be "locked out" with the shifter in fourth but the trans isn't locked in fourth. Didn't somebody say that two pages back? Worse than tires and WDHs!

jack

[Thomas G.]

Originally Posted by rabbit

More semantic hunting than gear hunting here. What's all the stir over the word "locked"? I've never had one of those +\- shifters and only one automatic trans in 40 yrs of driving. Seems to me lower gears are always available whatever the chosen gear and higher are not. Fifth gear can be "locked out" with the shifter in fourth but the trans isn't locked in fourth. Didn't somebody say that two pages back? Worse than tires and WDHs!

jack

I think the confusion is over locking the transmission into a single gear or gear range versus locking the torque converter, which has an internal clutch that prevents slippage. When the torque converter is slipping it is generating heat in the transmission oil.

[rabbit]

Well tarnation! Pops needs to put in his ear horn don't he?

jack

Should read 50yrs of driving. I guess a lot of that was only steering cause I didn't usually have much idea of what made em go til they didn't.

[Carol H]

Originally Posted by rabbit

Well tarnation! Pops needs to put in his ear horn don't he?

jack

ROFL - ..... add to that the simple problem that comes about due to not all of us having the same automatic transmissions and some have automatics with 3 different modes you can put them in, that all act very differently from the other in regards to what they actually do re lock out & shifting. so if it all sounds confusing to you I assure you your not alone.

[Jared J]

It's pretty easy to tell if mines locked, the rpms don't change going uphill.

[Brian B-P]

Originally Posted by Mike Magee

In high gear (5 for my HL), when under some strain the RPMs will climb by about 500. It's not a shift to 4, because a shift would raise RPM about 1000. So I figured this rise in RPM was attributable to slippage in the TC.

Since I have never observed a similar phenomenon when the SelectShift is in 4, 3, or 2 I assumed that the TC was locked up and preventing slippage. Is this an invalid asumption?

Unlocking the torque converter (TC) will change the speed by the amount that the TC slips when in "coupling" mode. That should only be about 10% of the engine speed, so unless that 500 rpm change occurred at nearly 5000 rpm, it is likely both the TC unlocking, and the TC moving into torque multiplication or "acceleration" mode... which is the reason to unlock.

In torque multiplication mode, the TC's output (to the rest of the transmission) is slower but with more torque than the input (from the engine); this is like using a lower gear, but is not limited to a fixed ratio so small engine speed changes are possible. It's not just slippage; it's more like a belt reduction drive that's slipping a bit. The lower overall gearing and thus higher engine speed allows the engine to produce more power (deliver more torque to the wheels at the same road speed), so the transmission control does this when high power is demanded.

In lower gears (due to driver selection) even more engine speed may not be required, so the TC may not unlock under similar conditions.

While I would like to be able to see the transmission's current operating mode, I believe that it would be a pointless distraction for most drivers at all times, and even for the few knowledgeable and enthusiastic drivers most of the time. On the other hand, knowing which gear selector position to use for towing, and if any of them actually result in a suitable transmission operating mode, is valuable.

[Joseph A.]

Originally Posted by deryk

Jeff with the Rav4, probably going to have to look into airsprings or a weight distribution hitch because they have a soft rear end. Look at my album and check the pic with the rav4 connected to my new ParkLiner...Im trying airbags first to see if the "squat" gets better... if not a wdh

deryk

Hey Deryk,

Another option to use with/without airbags is the OEM rear springs from the 2006-2012 Rav4 with 3rd row seat. The 3rd row seat equipped Rav4's have approx 300 lb extra payload capacity, as a direct result of the stiffer rear springs. The stiffer rear springs are the only modification to the rear suspension for 3rd row models. They use the standard (soft) shock absorber from the limited and base models.

Toyota part number for the springs is: 48231-0R050 (you need 2x)

That is the part number for LH & RH rear springs for the 3rd row model, either the Limited or Base.

I have a 2009 Rav4 Sport, AWD V6, with the tow package. I swapped the stock rear springs (which are the same as the base and limited 5 seater models) for the 3rd row springs. Cost was $257 CDN for both, taxes in.

Installation was easy, got the trucklet on a hoist, removed rear wheels, removed nut and bushing from left and right swaybar links (at bottom of lower control arm), supported lower control arm with trans jack, removed 17mm bolt from outboard lower control arm, lowered trans jack, removed old spring, cleaned spring perches/rubber isolaters, installed new springs.

Total remove/replace time was 2 hours, going very slowly...

These were installed to prepare the Rav4 for a Coachmen Clipper 16B, which will use a WD hitch from Husky, part number 31330:

WEIGHT DISTRIBUTION HITCH, TRUNNION BAR: FULL SIZED TRAILER

PIN TRUNNION BAR, Complete with Shank Assembly

Model: Lightweight
Tongue Wt. Range: 300-500 lbs
Max Gross Trailer Wt.: 5,000 lbs
Part #: 31330

I also installed the OEM Toyota Class III receiver assembly. It was about 2x the cost of aftermarket, but uses 26 bolts to spread the load compared to 4(!) for the aftermarket receivers...

Hope that helps! I joined this forum just to share the 3rd row spring info with you LOL!

[Jon Vermilye]

Probably useful, as long as you do the springs yourself. I asked my local dealer to replace the springs & they said NO!

[Mike Magee]

Originally Posted by Jon Vermilye

Probably useful, as long as you do the springs yourself. I asked my local dealer to replace the springs & they said NO!

They sound mighty stuck-up. I'm sure there are plenty of independent shops nearby that would love to have the business. Sounds like an install even my tire store up the street could handle.

[Joseph A.]

IMHO, the 3rd row springs are the medicine for rear squat on the Rav4, assuming you dont have the 3rd row model already! Airbags added to the stiffer springs will help further... And then a WD hitch to do the rest of the leveling maybe.

Bonus when you start with the Sport: Stiffer shock absorbers, a good combo with the stiffer springs. Rear end is planted and secure!

[Joseph A.]

Originally Posted by Jon Vermilye

I asked my local dealer to replace the springs & they said NO!

Well, better off buying the springs online, and installing them yourself, or someone you trust. The dealerships NEVER have given me any sense of confidence...

[honda03842]

Jon,

In your case I'd hunt up an independent Toyota repair shop. I'm sure it will cost less than a dealership.

[Joseph A.]

One interesting piece of towing info:

Australia Spec V6 Toyota Rav4's (which appear to be IDENTICAL mechanically to North American Tow Prep V6's) are rated to to tow 1900 kgs (~4200 lbs!) vs our 3500 lb cap...

Could it be our litigation happy environment??

Towing Capacity - Toyota RAV4

[Jon Vermilye]

Originally Posted by Joseph A.

One interesting piece of towing info:

Australia Spec V6 Toyota Rav4's (which appear to be IDENTICAL mechanically to North American Tow Prep V6's) are rated to to tow 1900 kgs (~4200 lbs!) vs our 3500 lb cap...

Could it be our litigation happy environment??

Towing Capacity - Toyota RAV4

It may be, but towing a 3010 lb (actual weight loaded) 17B with a RAV4 sport, I wouldn't even think of adding another 1200 lbs. The RAV4 does OK, but you can tell that on hills it is often working hard.

[Nancy]

Joseph,

Welcome to the group. Thank you for bringing to our attention the stiffer springs for the RAV4.

We will have our hitch, wiring, and brake controller installed tomorrow. Since we have one of the lightest Scamps (our tongue weight is less than 200) I am hoping we will not need any additional equipment, but your suggestion is one we will remember.

If you haven't yet checked out the rally thread please note the gathering in St. Malo in August. I think your parks start the registration In April. All the super sites are gone beforeI wake up. We go for non electric site so have our pick.

Hope to see you at St Malo.

Nancy

[Brian B-P]

Originally Posted by Jon Vermilye

I asked my local dealer to replace the springs & they said NO!

Originally Posted by Mike Magee

They sound mighty stuck-up. I'm sure there are plenty of independent shops nearby that would love to have the business. Sounds like an install even my tire store up the street could handle.

I doubt there is any technical difficulty with performing the installation. It seems more likely that the dealer is unwilling to use non-standard parts for critical components of the vehicle.

In this case the change seems reasonable, but when unloaded, and not carrying around the extra weight of the 3rd row seat, the front to rear spring stiffness and roll rate balance may not be appropriate. Watch the empty handling carefully for oversteer, especially over bumps or during deceleration.

[Carol H]

Originally Posted by Joseph A.

One interesting piece of towing info:

Australia Spec V6 Toyota Rav4's (which appear to be IDENTICAL mechanically to North American Tow Prep V6's) are rated to to tow 1900 kgs (~4200 lbs!) vs our 3500 lb cap...

Could it be our litigation happy environment??

or it could simple be as has been mentioned many times when this topic of tow ratings outside of North America that the cars are simple not the same cars as they probable have a number of different components Many times the differences between the cars is pretty clear - different engines and different rear suspension components both of which will and can impact tow ratings. We in NA want a smooth ride and the majority don't want a diesel engine or so the vehicle manufactures seem to think. :-)

[JungleJim]

Originally Posted by Joseph A.

IMHO, the 3rd row springs are the medicine for rear squat on the Rav4, assuming you dont have the 3rd row model already! Airbags added to the stiffer springs will help further... And then a WD hitch to do the rest of the leveling maybe.

Bonus when you start with the Sport: Stiffer shock absorbers, a good combo with the stiffer springs. Rear end is planted and secure!

Has anyone heard if Joseph A. was happy with how the new springs worked out? I have the exact same vehicle. I'm seeking feedback from someone about how effective the springs switch is.

[Joseph A.]

Originally Posted by JungleJim

Joseph,

I saw your post about replacing the RAV4 Sport springs with the 3rd row springs.
We have a 2009 RAV4 Sport and have terrible rear end sag while towing our light weight 1000 lbs camper. It has about 179 lbs tongue weight.

1. Did you have positive results? Do you feel that there was any improvement?

2. Do you think you still need to add helper air bags?
I read on the RAV4 forum that someone with the 3rd row couldn't fit the air bags because the springs had a smaller interior diameter.

I would greatly appreciate any experience you can share with us!

Thank you,
Jim

Hey Jim,

I posted your PM so that others looking for this info will be aable to find it too.

1. I have had very positive results. I never tried towing without the 3rd row springs, but with them we've had no issues. There is slight rear sag without the WD bars loaded, but once I tighten those chains, all the sag is gone. That is pulling a Coachmen Clipper 16B, probably about 350-400 lbs tongue. The trucklet sits level fully loaded, and handles just fine. The WD hitch is very important on this setup. The WD trunnion bars I have are pretty light, compared to the standard uniits out there.

2. I would not even think of using airbags at this point. The current setup is that good.

3. I have towed now approx 5000 km since May with this setup, through the Rocky Mountains, through the prairies, etc. From Manitoba to BC and back, with a few shorter trips in between...

Hope that helps!

-Joseph