Kia Forum banner

1 - 20 of 41 Posts

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #1
I started a discussion (4WD system) which didn't seem to gain any definitive answers regarding the TOD system (2 setting switch, 4H Auto 4L ONLY) on the Sorento. I have received the factual answer from Borg Warner which I will copy into here.

Basically, if like me you've been told that in Auto mode the torque transfer to the front wheels occurs "regardless of power / throttle settings", then you've been misled, it doesn't. So if you're going downhill in slippery conditions using engine breaking and / or no throttle then you are driving a TWO WHEEL DRIVE (rear) ONLY. I believe this has the potential to catch the unwary out in the worst possible way with an out of control downhill slide with the only potential solution being to put power on to get some front end traction.

If you're in 4L however you don't have a problem.

Guess it come to this, if you're concerned about front end traction in this kind of situation the ONLY SAFE way is to engage 4WD LOW.

Cheers

Derek

Here's the actual response from Borg Warner


Dear Derek:

In response to your question: As configured in the Kia Sorento, the TOD
system has just two operating modes:

* In the on-road 4H "AUTO" mode, the on-demand clutch is activated
only when loss of rear-wheel traction is detected under power. Thus in
"AUTO" mode, the clutch is not activated when coasting at low or zero
throttle, thus, your information is correct... engine braking torque
transfers only through the rear wheels.

* When operated in 4WD LOW, the on-demand clutch is fully engaged at
all times, regardless of throttle opening. Thus, engine braking torque is
distributed through all 4 wheels.

The TOD system can be programmed to operate in a 4WD High Range Locked mode
with the clutch fully applied at all times... as in a Ford Explorer, for
example. Kia has not chosen to offer this mode of operation in the Sorento
to date.

Regards,

Bob Blakely
Manager, Market Research & Planning
BorgWarner Transmission Systems
3800 Automation Avenue
Auburn Hills, MI 48326
Office: 248-754-0257
Cell: 248-330-2585
Fax: 248-754-9257
[email protected]
 

·
Banned
Joined
·
417 Posts
I am really happy I don't have this TOD 4wd transfer case in my 03 Sorento. This would really not be something for anyone to find out the hardway. :( Just what do you plan on doing now that you understand how your 4wd works?
 

·
Registered
Joined
·
1,036 Posts
If you encounter conditions that would possibly lead to a slide whilst going down a steep hill, you should be in Low range anyway, maximum engine braking will occur in low range, thus maximum control.
 

·
Registered
Joined
·
3 Posts
Here in Spain we are working all together in a user forum to find out a solution for this TOD system problem. If u want further info on this issue click http://miarroba.com/foros/ver.php?foroid=2...=3230686&pag=10 and u will have lots of sorenters´ opinions and "home" made solutions.
Fortunately I made up my mind 4 a manual traction switch model called EX 1 in my country (2 H-4H-4L). Anyway Kia is aware of this problem in Spain thanks to these forum mates; let KIA know in your countries about this problem OFFICIALLY, this way we will manage to make more pressure on the make to give us a FINAL SOLUTION.
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #5
Hi again

Thanks for the replies guys, will have a look at the spanish site. I've emailed Borg Warner again to see if there's an over-ride system I can fit. I agree that being in 4WD L is the solution to downhill problems it's just being AWARE that you're NOT in 4WD if you're "caught out" in that situation (downhill slippery) in H ratio taht I think is important, it could mean you have to deal with the problem entirely differently to be safe.

Cheers

Derek
 

·
Registered
2003 Kia Sorento
Joined
·
606 Posts
I'm not sure you're looking at the system as a whole. If you're in a situation where you're heading downhill on a steep grade, it DOESN'T MATTER if the TOD clutch is locked or not because you aren't driving the front wheels anyway, you would be braking. Especially if you're concerned with traction.

The whole principle of 4-wheel drive is to drive the front wheels when the rear wheels may loose traction (or not offer enough). The brakes are what's going to stop you, not the 4-wheel drive no matter what gear you're in, or if the rear wheels have traction or not. If you're in 4-wheel high, TOD or standard, the torque converter is unlocked anyway when you're off the throttle so the engine would offer minimal braking, even if the TOD clutch was engaged. The lower gears in the transfer case is why you notice that you slow down more when you're in 4-low.
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #7
Hi again

Sorry can't get into the Spanish site through that link, just get a HUGE page with nothing on it.

Derek
 

·
Registered
Joined
·
2 Posts
Hello, I own one Kia Sorento EX2 2.5 CRDI it has the ATT sytem (automatic Torque on demand). On my opinion this system has a dangerous snag. If you go down along a dramatic slope on Low 4WD a bit sliding floor and you don´t press the gas pedal over the 1800 rpm you will have problems. You want the engine break on this situation, because if you break you will lost the control. But the automatic 4WD don´t set the forward traction although on Low. So you will accelerate because the rear low weight in a slope make to slip the rear axle, the weigh is on the forward axle.

And this problem will increase if you have to turn on a dramatic slope curve. You feel how the rear deviate from course.

Taste it, but take care. :thumbsup:
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #9
Hi edusuco

Not true according to Borg Warner because in Low ratio it is always split 50/50 between the front and rear wheels so you don't need 1800 revs to get the front end driving or gripping in this case. I only see a potential problem in high ratio when you may think that the front end has traction and doesn't.

Cheers

Derek
 

·
Registered
Joined
·
153 Posts
Derek,

I am sorry to break you the bad news, it seems that the guys from Spain do not make themselves clear:

Follow the links in this thread one of them leads to a video clip that shows the problem.

And look here, they have electrically tested the problem, it exists in 4L

It may happen that BorgWarner fixed the problem in later models but the problem existed in 4L, at least in the Terracan.

The only way to clear the issue is to test it as I suggested in the other thread.

Ilan
 

·
Registered
Joined
·
79 Posts
I don't really understand this issue. If you are going downhill in an automatic you don't get any engine braking effect in the same way that if you are on a flat road surface, when you lift off the accelerator, the car keeps going and doesn't immediately start to slow down.

If you are in the habit of relying on engine braking, you should have a manual Sorento with a physical link between the engine and the driven wheels.

The driven wheel balancing is driven by torque demand (ATT), going downhill torque demand will be at the lowest level therefore unless in Lo you will have the minimum drive (10%) to the front wheels anyway.
 

·
Registered
2003 Kia Sorento
Joined
·
606 Posts
Sorentoman, you nailed it on the head. Well put.

Ilan, I'm not sure what those links go to, but at the time I'm writing this neither of them work. I'll try again later because I want to see whatever these tests are.

I don't see any problem here, except maybe that the people using the TOD system should have got the EST system if you wanted to 4-wheel. It operates exactly as Borg Warner says it does. If you're going down a steep hill, who cares if the engine is making the front wheels turn.

It's not. Gravity is. You're using the brake, so the engine, transfer case, transmission, drive shaft, and differential could all be missing, and it won't affect the way it drives down a hill or the traction you get at any of the wheels for any reason (other than the weight difference if these parts were really absent).

The TOD system is more for icy road or sand, not packed dirt. It's 95% friendly,meaning that the 95% of people with 4-wheel drive vehicles who don't actually go off of the road would be happy with it.

The only time the TOD is active is when the rear wheel sensors tell the transfer case ECM that the rear wheels are spinning faster than the front wheels are. Then the transfer case ECM transfers power to the front wheels until they spin at the same speed as the rear wheels (also slowing down the rear wheels, because it's splitting the difference). This happens until there is equal torque being applied to the front and rear wheels. The transfer case ECM will never allow the front wheels to spin faster than the rear wheels at any time.
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #14
Man, talk about round and round and round, who's right ? who's lying ? why ? surely the manufacturers know how it's set up ? frankly I'm getting more and more concerned about this issue, does anybody know of any way to contact Kia to get an honest answer ? My opinion is that it almost doesn't matter what the answer IS as long as we know !! I want to know when I start to slide if I should consider using some power to increase front end traction or not !!!!

Derek
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #15
By the way, for all those who seem to think it doesn't matter, have a look at the last few paragraphs of the Terracan site info (link above), it should scare you enough to want to know if you ever go downhill in slippery conditions and want to able to steer the front end of your vehicle, after all that's what 4WD SHOULD allow you to do !!!

Derek
 

·
Registered
2003 Kia Sorento
Joined
·
606 Posts
He put a lot of time into that test, but didn't duplicate the most important part that makes the sytem work...front and rear wheel speed differences.

Take a look at his "Auto Mode" chart. The only time he actually slips the wheels is when he dumps the throttle and causes the rear wheels to spin. Obviously if the transfer case suddenly shifted 50% of the torque to two, almost non-rotating wheels it would self destruct. That is not a flaw.

The same chart notes that some torque is transferred at lower throttle levels, without the wheels spinning. Is this a flaw? Well, no. As you accelerate, weight transfers to the rear, making the tires physically smaller and the front tires physically larger. This makes them turn at different speeds, so still, it's acting as designed and trying to shift torque to the front wheels so that they spin at the same speed. Still, no flaw.

Now, on to the "Low Mode" test, where wheel slip doesn't matter. He notes "bad news" because the transfer didn't happen while he was stopped? Was the transmission in "N" like it's supposed to be? Does he know that after you stop, shift to neutral, switch to 4-Low, and then shift to drive that it takes a few seconds for the rear to shift down? He didn't note this, so lets move on.

He lets off the accelerator at less than 1200rpm (almost idle), and the front wheels lose torque. Sharp turning is done at idle speeds, which is very hard on the transfer case and can ruin it if it's locked, or at least shorten the life. One more time, no flaw.

The last bit of bad news is when he notes that at less than 1200rpm, while braking, the front loses torque. It's the same test as when he just let off of the accelerator, the brakes don't matter.

He's also got some "conclusions", but this book is long enough. Maybe another day.

Got to give him credit though, he put more time into the test than anyone else has.
 

·
Registered
Joined
·
153 Posts
A 4X4 truck in low mode should be locked 50:50 front rear all the time! No excuses no stories. I would not take such a truck for serious off roading knowing that here and then I may be in 2wd. (look at the video in one of the links above).

Bob from Borgwarner says it in is answer:
“* When operated in 4WD LOW, the on-demand clutch is fully engaged at
all times, regardless of throttle opening. Thus, engine braking torque is
distributed through all 4 wheels.”

If he is correct then there is no issue.

A simple test will solve all the questions
1. Start the Sorento.
2. engage 4L.
3. put in into neutral.
4. Put all 4 wheels in the air (this is the difficult part).
5. turn one of the front wheels - if one of the rear wheels is turning then the clutch is engaged and all OK.
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #18
Hi Ilan

I agree totally, if it is in 50/50 ALL THE TIME in low ratio there's no issue, if it isn't !!!!!!!?????? there's a BIG ISSUE. Mine isn't even in the country yet so I can't do any tests but maybe somebody has access to a service lift that works on the chassis rather than the wheels (I'm sure our local service garage has one like that otherwise they wouldn't be able to take the wheels off with the car on the hoist) to try this out, if not I'll just have to wwait and try it with mine.

Don't get me wrong I still want my Kia (had a look at them again yesterday as they've just opened a new showroom here) and went through a box of tissues wiping the drool off my chin !! I just want to know the truth so I know what to do down hill in slippery conditions, surely that's not too much to ask for what is supposed to be an excellent off-road vehicle !!!!!!!!!

Cheers

Derek
 

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #19

·
Registered
2008 VW Tiguan (sold my Sorento)
Joined
·
355 Posts
Discussion Starter #20
Yep me AGAIN

Ilan, wouldn't it have to be in gear rather than neutral for the test to work ? otehrwise nothing would be linked up ? if you simply put it into gear and made sure that all 4 wheels were turning at low revs wouldn't that prove it was working on all 4 ?

Sorry but when mechanical and electrical issues come in my knowledge is ZIP.

Cheers

Derek

PS: Realise it's all summer and sunshine in the States but it's winter, snow, ice and slippery here so I guess that's why I'm more interested in this !
 
1 - 20 of 41 Posts
Top