Towing with Sienna/Rav4/Highlander? - Page 5 - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 01-17-2013, 08:55 PM   #57
Senior Member
 
Mike Magee's Avatar
 
Name: Michael
Trailer: Li'l Hauley
Oklahoma
Posts: 5,145
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.

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?
__________________

__________________
How much time do we have left? 2 Chr. 7:14
Mike Magee is offline   Reply With Quote
Old 01-18-2013, 06:53 AM   #58
MC1
Senior Member
 
MC1's Avatar
 
Name: Wayne
Trailer: Nest fan, Airstream Sold
Ontario
Posts: 2,006
Quote:
Originally Posted by Mike Magee View Post
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.
I have seen the same RPM increase (actually about 300 RPM increase) in similar situations. I too believe it to be the electonics knocking it out of TCLU*.

*torque converter loc up.
__________________

__________________
MC1 is offline   Reply With Quote
Old 01-18-2013, 10:04 AM   #59
Senior Member
 
Jon Vermilye's Avatar
 
Name: Jon
Trailer: 2017 Escape 21
Oswego, NY
Posts: 1,408
Registry
Quote:
Originally Posted by MC1 View Post
I have seen the same RPM increase (actually about 300 RPM increase) in similar situations. I too believe it to be the electonics knocking it out of TCLU*.

*torque converter loc up.
That is the way I've always identified the TC unlocking. I do wish there was a manual lock available, but I suspect it would cause more problems than it would solve for non - towers...
Jon Vermilye is offline   Reply With Quote
Old 01-18-2013, 10:17 AM   #60
Senior Member
 
Thomas G.'s Avatar
 
Name: Kinga DeRode
Trailer: For Sale Or Rent
Rooms to Let 50 Cents
Posts: 5,103
Maybe something like a scan gauge can be set to identify this.

Years ago I used to tune the internal dampers in torque converters and I had the transmission engineers build a box that identified what gear it was in, whether the converter was locked and also has a manual locking switch. It helped a lot as it is difficult to tell just from cues from the tachometer.
__________________
UHaul and Burro owners, join the UHaul Campers on Facebook. https://www.facebook.com/groups/529276933859491/
Thomas G. is online now   Reply With Quote
Old 01-18-2013, 10:19 AM   #61
Senior Member
 
Carol H's Avatar
 
Name: Carol
Trailer: 22' Airstream Formerly 16' Scamp
British Columbia
Posts: 11,731
Registry
Quote:
Originally Posted by Mike Magee View Post
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?
Carol H is offline   Reply With Quote
Old 01-18-2013, 12:41 PM   #62
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
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
__________________
rabbit is offline   Reply With Quote
Old 01-18-2013, 12:46 PM   #63
Senior Member
 
Thomas G.'s Avatar
 
Name: Kinga DeRode
Trailer: For Sale Or Rent
Rooms to Let 50 Cents
Posts: 5,103
Quote:
Originally Posted by rabbit View Post
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.
__________________
UHaul and Burro owners, join the UHaul Campers on Facebook. https://www.facebook.com/groups/529276933859491/
Thomas G. is online now   Reply With Quote
Old 01-18-2013, 02:23 PM   #64
Senior Member
 
rabbit's Avatar
 
Name: Jack
Trailer: '98 BURRO 17WB
Delaware
Posts: 2,548
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.
__________________
rabbit is offline   Reply With Quote
Old 01-18-2013, 02:48 PM   #65
Senior Member
 
Carol H's Avatar
 
Name: Carol
Trailer: 22' Airstream Formerly 16' Scamp
British Columbia
Posts: 11,731
Registry
Quote:
Originally Posted by rabbit View Post
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.
Carol H is offline   Reply With Quote
Old 01-18-2013, 03:04 PM   #66
Senior Member
 
Jared J's Avatar
 
Name: Jared
Trailer: 1984 19' scamp
Kansas
Posts: 1,610
It's pretty easy to tell if mines locked, the rpms don't change going uphill.
__________________
Jared J is offline   Reply With Quote
Old 01-21-2013, 05:58 PM   #67
Senior Member
 
Brian B-P's Avatar
 
Name: Brian
Trailer: Boler (B1700RGH) 1979
Alberta
Posts: 5,000
Quote:
Originally Posted by Mike Magee View Post
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.
__________________
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.
Brian B-P is offline   Reply With Quote
Old 03-17-2013, 12:49 PM   #68
Junior Member
 
Name: Joseph
Trailer: Coachmen Clipper 16B
Manitoba
Posts: 11
Quote:
Originally Posted by deryk View Post
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!
__________________
Joseph A. is offline   Reply With Quote
Old 03-17-2013, 01:31 PM   #69
Senior Member
 
Jon Vermilye's Avatar
 
Name: Jon
Trailer: 2017 Escape 21
Oswego, NY
Posts: 1,408
Registry
Probably useful, as long as you do the springs yourself. I asked my local dealer to replace the springs & they said NO!
Jon Vermilye is offline   Reply With Quote
Old 03-17-2013, 02:09 PM   #70
Senior Member
 
Mike Magee's Avatar
 
Name: Michael
Trailer: Li'l Hauley
Oklahoma
Posts: 5,145
Quote:
Originally Posted by Jon Vermilye View Post
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.
__________________

__________________
How much time do we have left? 2 Chr. 7:14
Mike Magee is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Towing with a rav4 Jimmy jones Towing, Hitching, Axles and Running Gear 5 08-13-2012 11:52 PM
Highlander towing ability ginnymce Towing, Hitching, Axles and Running Gear 7 10-17-2011 07:28 AM
Towing with Rav4 Edward Shook Towing, Hitching, Axles and Running Gear 1 07-08-2008 08:19 PM
Towing with Toyota Sienna 3.3L Alan P. Problem Solving | Owners Helping Owners 7 05-29-2007 11:31 PM
Better tow vehicle. Highlander vs. Sienna van Gary Little Problem Solving | Owners Helping Owners 6 08-31-2006 12:49 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:34 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.