Stupid ? but I need to settle a bet. "Binding Gears."

[Tony5150RN]

Ok, I have no shame in admitting that I'm rather new to 4WD's. Although I did drive them occasionally, a long time ago when I worked Volunteer, and Part-Time, for a Fire Department, I have only owned one, and for a short period of time; until now.

Mrs. 5150, has no experience, whatsoever, with 4WD's except for those she sells. Anyway, she is trying to tell me that I shouldn't drive the FJ, in 4WD, on dry pavement. In addition, she's trying to tell me that the I shouldn't use 4WD at all while on the interstate, at moderate to fast speed, in pouring rain. She tells me that the people she works with have advised her that using 4WD on the interstate, or on dry pavement, could "bind the gears."

I have never heard such a thing in the past. can anyone shed some light on this?

[iamnid]

I don't know about "binding the gears" but other than that she is right -- you generally shouldn't drive in 4wd on dry pavement.

[highbeams]

ok first, we are talking PART TIME 4x4 here
second, yes do not use 4x4 on dry pavement , the correct term is Driveline bind, and it can break stuff
in snow or slippery rain, you can engage 4x4 as now the surface is a HIGH SHEAR surface. but when it gets dry, back to 2wd

[tractorlegend]

Your wife is right just this once.
There is no "slip" built in like on an AWD vehicle.
This makes them better in situations where utmost traction is needed,
but some driver interaction is required as the tradeoff.


I have figured out The Hokey Pokey is really what it's all about

[highbeams]

Trac, I think POURING RAIN on a HIWAY is a signifacant slippery surface for 4x4

[lllateralus]

as long as the center diff is unlocked (like a 6mt FJ in 'daily driver mode') there will be no binding.

When the center diff is locked (like a auto FJ in 4hi, or manual FJ in hi-lock)
then there will be serious binding when turning on pavement.

So, in reference to part time systems,(and the manual FJ with center diff locked) she is 100% correct.

[Topless4runner]

lllateralus previously said:

When the center diff is locked (like a auto FJ in 4hi, or manual FJ in hi-lock) then there will be serious binding when turning on pavement.

while everything else you said is correct, the fact of the matter is that the part-time 4wd FJ Cruiser does not have a center differential, locked or otherwise; thats why it cannot be driven on dry tarmac in 4wd. its output is fixed 50/50 f/r all the time, when in 2wd you are simple disengaging the front output shaft on the t-case.

[lllateralus]

I know, I was trying to simplify the systems for the sake of explanation.

The auto FJ has the same type of 4WD system as other yota 4x4's.
(vacuum op. ADD front diff and no center diff)

[RoverGGM]

I may be mistaken, but I believe the front Auto-Disconnect-Differential (on the FJ Cruiser) is electrically operated instead of vacuum.

[cruiserlarry]

Tony5150RN previously said:

Ok, I have no shame in admitting that I'm rather new to 4WD's. Although I did drive them occasionally, a long time ago when I worked Volunteer, and Part-Time, for a Fire Department, I have only owned one, and for a short period of time; until now.

Mrs. 5150, has no experience, whatsoever, with 4WD's except for those she sells. Anyway, she is trying to tell me that I shouldn't drive the FJ, in 4WD, on dry pavement. In addition, she's trying to tell me that the I shouldn't use 4WD at all while on the interstate, at moderate to fast speed, in pouring rain. She tells me that the people she works with have advised her that using 4WD on the interstate, or on dry pavement, could "bind the gears."

I have never heard such a thing in the past. can anyone shed some light on this?

She is partially correct. If your FJ is a six-speed manual trans, it has a full time 4wd system that uses a viscous coupler to allow for slippage between the front and rear wheels on dry pavement. This is neccessary because the front and rear turn at different speeds around corners, etc., and without some slippage the transfer case would bind = damage. If you have an auto trans, its a part-time 4wd system. When you engage 4wd, the part-time mechanical transfer case cannot allow for slippage, and if the ground won't give, your transfer case will = damage. However, in wet conditions, or snow covered roads, or off-road where the road itself allows the tires to slip, 4wd can safely be utilized. I've been using 4wd on wet paved roads for 30 years without an incident, but you must shift back into 2wd when the road conditions do not allow for tire slippage. Basically, if you could safely drive a standard car or truck on the road, don't use 4wd...