There are 3 different AWD systems used on the first Gen HL. (My opinion - I don’t call it 4WD unless it has a low range) What year and trim is of interest?

 

The 4WD system on the non-Hybrid models is a full time all wheel drive system(constant 50:50 split front and rear wheels); hence the 4WD badging. The hybrid models get the more modern intelligent AWD system that can apply traction to the front and rear wheels based on traction needs.

The HL transfer-case, drive-shaft, and rear differential are the mechanical linkages. Our 4WD system just have only one gear ratio or range.

 

Our cars do have a mechanical AWD system and a small center differential inside the transaxle vs, the newer 14+ Highlanders that use an electronic coupler to send power to the back

See: Toyota 4WD review (2)

 

Our cars do have a mechanical AWD system and a small center differential inside the transaxle vs, the newer 14+ Highlanders that use an electronic coupler to send power to the back

See: Toyota 4WD review (2)

Nice information, but you should have posted the Toyota review part 1 to apply to FWD (FF)models like our Highlander. Our HL fall under the information as STD II type for the older 2000-2003 models(with the Torsen LSD option) or the VSC+ type for the 2003 -2007 models(brake system used for wheel slippage). However, the posted information is based off the Australian market it seem so the models options will be slightly different than the U.S. market models.

Toyota 4WD review (1)

Description of Toyota 4WD different types (initially FF cars)

toyota-club.net

 

I too am really confused as to the 4wd or AWD system. I just bought my base 2004 today. Nooooo idea what the heck it has. I dont see anything to turn on/off 4WD or AWD. Heck it might just be a FWD. Help!

 

If it's got a rear differential, it's got 4 driven wheels, full time (call it what you want). All of the vehicles equipped with VSC have open differentials... so talk of "torque split" is kinda moot as far as I'm concerned. All have limited (very limited) "traction control" capability via automatic engagement of brakes on slipping wheels.

 

I invite you to come snow drifting with me in my RX with the LSD and viscous coupler transfer case that 01-03 Highlanders and 99-03 / 07-09 RX got 😉

The VSC AWD system IMO is a bandaid solution for the VC t-case and Torsen LSD that this platform used to get. Similar to the "E-LSD" in my friend's GTI, just couldn't compare to the real thing. It'll help you if you screw up and come in too hot into a corner, but that's about it. When driving these 04+ the power being cut was always a bother to me. Had to turn off VSC to get out of a muddy farm in a family member's 14 HL

2nd gen RX MZ engine AWD ^ (Same as 04-07 HL)

2nd gen RAV (VC transfer case ^ no VSC but open rear diff)

I'd love to see how a Torsen-equipped RAV or RX300 would do in this test

 

Your LSD retrofitted RX350 has the best features of both of the older 4wd and newer AWD systems. It has the stock VSC system to control the wheel slippage in the front axles and the modified mechanical LSD to control wheel slippage in the rear axles.

However, your modified RX350 is a rare custom built option that is not available as a stock option.

Note: If the AWD system do not have an AWD lock button(or full time AWD) then it is required to turn off the traction control to get out of mud or an icy patch on most modern cars with AWD on nearly all makes. However, the RX350 AWD system is a pretty weak performer to be honest.

 

More advertising blurb info we got in Australia. The Toyota 4WD review discussed by Lowlander and carguy75 is of course a much deeper explanation over the differences (of which there are many and for which I'm still trying to get my head around).

So basically the Highlander 4WD system gives the car extra momentum courtesy of the viscous centre LSD if either the front or rear starts slipping (and provided all 4 wheels are still on the ground)? So useful when there are slippery patches not exceeding the distance between front and rear axels?

 

The centre diff in these is in the transmission, it's the same or very similar of a unit between the U140F and U151F, which then couples to the transfer case. They marketed the 2007-2009 RX350 as having a "limited slip centre diff", but in reality all it is was the MF2AV viscous coupler transfer case from the 2001-2003 Highlander. They even have the same part number from Toyota.

04-13 HL, 04-06 RX330, 04-10 Sienna

99-03 RX300, 01-03 HL & 07-09 RX