Last post on Aug 21, 2013 at 5:16 PM
You are in the Toyota Sequoia
What is this discussion about?
Toyota Sequoia, Toyota Highlander, Toyota 4Runner, Toyota Land Cruiser, Toyota RAV4, Toyota Tacoma, Truck, SUV
#331 of 2493 Tundra 4x4 or 4x2
Mar 26, 2002 (9:54 pm)
I am planning to buy a 2002 4x4SR5 V8 with ABS andLSD or a 4x2 Tundra V8 XCab with ABS, LSD and off road package plus other options. From all my readings on this thread the Tundra 4x4 systems is different from what is on the Sequoia and Land Cruiser.
My off road driving will be mostly trails and the beach about 3-4 times a year. I live in Southern California.
I wanted to know that since Toyota now offers a LSD on the 4x4 and 4x2 has it changed the 4WD system on the 2002 Tundra.
I have also read that the 4WD system on the Tundra can't be used on dry pavement and will damage the transfer case, while the Sequoias and Land Cruisers can with no damage. Too bad Toyota did not put the same 4WD system used on the SEQ and LC on the Tundra.
I appreciate your opinions.
Mar 26, 2002 (10:11 pm)
3 open diffs:
'Right up until the available torque exceeds the traction coefficient of any wheel or wheels, then ALL of the available torque will be routed to the wheel or wheels with the LEAST traction.'
That's the way it looks, but not the way it works. The open diff is a 50/50 split, no matter what (in theory anyway, sometimes they are more like 60/40 or vise versa dependent upon internal friction and other problems). When one wheel spins, the available torque is still split at 25/25/25/25, but torque to each wheel is now limited to the least amount of traction of that slipping tire. A slipping tire doesn't take very much torque to keep it slipping though, so it appears that all energy is going to that one tire, while it isn't.
Mar 27, 2002 (4:03 am)
I have heard that the Active TRAC system will be on future Tundras. Oh what a happy day that will be for pickup buyers.
Mar 27, 2002 (4:18 am)
Try calling Toyota at 800-331-4331. They will be more than happy to answer your questions regarding the Sequoia and it's fantastic Active TRAC system.
#335 of 2493 sequoia real-life
Mar 27, 2002 (7:14 am)
I have driven the sequoia this winter on the freeway up steep mountain passes in the snow. At 65 mph there is no slippage or fishtailing of the rear, and there are no noises at all. The only time there is ABS pump noise is when you mash the accelerator from a stop or at slow speeds when on a snow covered road.
#336 of 2493 torque split
Mar 27, 2002 (7:15 am)
100Hp engine, three open diff'ls, one wheel raised off the ground, (or on ice, mud hole, etc.)its spinning only dissipates 25%(?) of the HP yet the vehicle doesn't move, where is the other 75% being dissipated?
Mar 27, 2002 (7:18 am)
What makes the engine develop 100 horses??? if the wheel spinning one let's say ice gets 5 ft-lbs of torque, then every other wheel is limited to 5 ft-lbs of torque (assuming 3 perfect open diffs). The engine can rev and it's power will go into rotational inertia, heat, noise...and those tires.
#338 of 2493 torque split
Mar 27, 2002 (7:21 am)
If the spinning is not stopped as in the sequoia system then all torque goes to zero or something close to it. No friction=no torque. Its like racing your engine in neutral.
#339 of 2493 re: torque split by gpm5
Mar 27, 2002 (7:23 am)
it's like racing your engine in neutral
#340 of 2493 Something to consider
Mar 27, 2002 (8:12 am)
wwest: I think one point you are not seeing in the differences between awd and 4wd is the dedication of torque in awd vs making torque available in a part time 4wd system. This is the principle difference between a 4wd system and an awd system.
The awd system with limited slip diffs and visc liq diffs can be designed to provide a minimum % of torque to a wheel under all conditions whether there is ice, gravel or dry pavement. No such minimum can be assured with the open diffs and tt4 traction system of a Sequoia.
Imagine the following scenario. Your vehicle is placed with all 4 tires on very slick ice at a standstill. In an awd vehicle, I know that in the case of the Denali 38% of the torque will be delivered to the front wheels and 62% will be delivered to the rear and because of the limited slip diff in the rear and the viscous center coupling.
I am assured that the tires will rotate even though they might spin. The vehicle will certainly move forward as it builds momentum.
I truly have no idea how the Sequoia will respond, however in a vehicle with open diffs the engineering would suggest the tires will not move. If they don't rotate the TT4 system has nothing to measure and no benefit is gained by braking a wheel thats not rotating. Exactly how is that a better traction system than one that guarantees power to all 4 wheels under all circumstances?