How much torque in front end?

[Stewe]

Hi,

I've just replaced the clutch in the transfercase it was only steel plates left. when I tried the four wheel drive this weekend I got myself stuck in a mud hole. I turn the knob into 4wd low, now to the question, the rear wheels skidded in the mud but the front wheels did not. I got out of the mud hole but it was not so much power on the front. Is it normal that the clutch is skidding when you run on 4wd low? or is anything wrong? in that case what?

I'm not whant to replace the cluch again because of a another fault

Thanks in advance
Stewe

 

[Stewe]

Hi again,

Is it possible that no one know this?
If you got stuck in a mud hole with 4wd low,
does the car skidds on one front wheel too or only on the rear wheels?

//Stewe

 

[IZwack]

Hi,

I would first make sure that the electromagnetic clutch is being powered up (via the infamous "brown wire"). Next, check to see if the vacuum disconnect in the front axle is activating.

 

[Stewe]

Thanks for the quick reply...

I've think the electromagnetic clutch is beeing engaged and the vaccum disconnector as well, because i get some power to the wheels but not that much so they spinn. but still I can feel that the 4wd helped me...

My thought is that, if the rear wheels spinns but not the front it must be some skidding in the clutch.

What do You think, it is OK to have it like this?

//Stewe

 

[IZwack]

Yes the clutch could still be slipping allowing only a certain amount of torque to get to the front wheels before it slips again.

I don't think its "OK" to have the front clutch slip since its supposed to be a 50/50 split of torque between the front and rear driveshaft. Also, the more slip the clutches undergo, the faster they will wear away.

But having said that, a clutch is a clutch and, under the right conditions (amount of torque, how stuck the vehicle is, and so on), any clutch will slip.

Does the 4LO light come on when you are in 4LO?

 

[Stewe]

Yes the light comes on, and i often hear the clunk sound when the low gear i engaged.
As I could see when I disassemble the t-case the TOD is used even on LO, rigth?
and if the friction on the rear tires is low then the TOD is not able to engage that hard, as I understand the t-case the TOD is dependant of the friction from the rear end, right?

//Stewe

 

[IZwack]

As I could see when I disassemble the t-case the TOD is used even on LO, rigth?
and if the friction on the rear tires is low then the TOD is not able to engage that hard, as I understand the t-case the TOD is dependant of the friction from the rear end, right?

Yes that is all correct.

 

[gijoecam]

The key to this problem would be whether or not the front driveshaft was turning. It's simple to diagnose. Jack the front end up, place it in 4 low, and see if you can turn the front driveshaft. If you cannot, it's not likely that the transfer case is the problem.

To verify that the front axle is engaging, spin one of the front wheels. The other front wheel should spin in the opposit direction. If it does not, there is a problem with the vacuum-actuated center-axle disconnect, either the disconnect itself, or the vacuum system that controls it.

Start there and let us know what you find.

-Joe

 

[Stewe]

Joe: The 4wd is engaged the problem is that the front wheels spinns "slower" then the rear wheels on low(even on auto but thats not that interesting, it's normal). When the rear tires is skidding the front tires does't.
i.e there must be some front clutch slip.
My question is how much slip is OK/normal on a 4405?

//Stefan

 

[gijoecam]

I guess that answer would be none. Setting the system to 4high (97-01 model years)or 4low (all second generations) locks (or is supposed to lock) the transfer case for a 50/50 torque split. The Transfer Case Clutch Coil is used to lock the case in 4high and 4low, as well as momentarily as needed in 4auto. The TCCC is controlled by the TOD relay.

Here's another question: On a loose surface, does 4auto work the way it should? Hold the brakes with your left foot and apply the gas with your right on a loose, gravel or dirt surface. Hang your head out the window or open door and watch the rear tire as you gently apply the gas to force the rear wheel to slip. The rear should get about 1/4-1/3 of a turn before the system momentarily locks the front axle, then unlocks, then re-locks, then unlocks, etc.

Now, do the same thing in 4low, and the front and rear should be locked together. If it functions the same way as it does in 4auto, that tells me that the system is not locking in at 100% like it should, and is relying on teh TOD system to stay locked.

Here's another way to check it: Place a mark on the bottom of the front and rear driveshafts. Lock the system into 4 low and do as I described above. Driving in a straight line, the front driveshaft should turn the exact same number of times as the rear, and the two marks should still be on the bottom at the same time and rotate in unison. Again, if they don't, the system is not locking in the way it should.

If the transfer case locks, but the front wheels do not turn, it's usually a problem with the center-axle disconnect as I mentioned above. The key is first determining whether or not the transfer case is locking as it should.

-Joe