question about 4hi

russellp

New Member
Joined
Dec 3, 2007
Location
Utah
I have a new automatic fj cruiser. I noticed today when I put it in 4hi, that when I cranked the wheel all the way to either side it behaved strangely. It just seemed a little shakey. Is this normal?
 
Were you on pavement or a soft surface ( dirt, gravel,etc.)?

On pavement, in 4wd, low or high will buck and shake.
4 wheels, all trying to travel at different speeds, especially if you have the lockers on.
 
I was on pavement. What are lockers? Its an 08 fj cruiser. You said on pavement it will buck and shake....does that mean it wouldn't on soft surface?
 
You probably don't want to be in 4wd while on pavement, not too good for it. and yes, on a soft surface where the wheels can slip it will be just like normal, no shaking
 
what you felt was probably the front axle u joints or cv joints at the knuckles "lurching". going straight, the cross of the u joint is equal, but turned, it binds, causing that feeling. like XJs said, its hard on your rig on pavement, because your forcing yout tire to slip on a high traction surface. in the dirt or mud, you wouldent hear, feel, or notice the binding or slipping. oh, btw, and u joints and cv's are weakest when their turned like that, so if you get happy with the skinny pedal, make sure your wheels are straight if posssible to keep the joints alive!
 
so what is it about the manual transmission version of the same car that allows it to be all time 4 wheel?
 
If it is full time there is some provision for slipping in the T-case.
 
ok so i know now not to engage 4wd on dry pavement. i'm wondering now if i could have already done damage from the few times i tried this....
 
damage highly unlikely....
 
bigjeeprob said:
what you felt was probably the front axle u joints or cv joints at the knuckles "lurching". going straight, the cross of the u joint is equal, but turned, it binds, causing that feeling. like XJs said, its hard on your rig on pavement, because your forcing yout tire to slip on a high traction surface. in the dirt or mud, you wouldent hear, feel, or notice the binding or slipping. oh, btw, and u joints and cv's are weakest when their turned like that, so if you get happy with the skinny pedal, make sure your wheels are straight if posssible to keep the joints alive!
Click to expand...
FJ Cruisers don't have u-joints near the knuckles.

Still, the tone of the thread is right. Your t-case isn't designed to have the front and rear wheels traveling at different speeds so you should only use 4wd in conditions where a tire can slip.
 
You can engage on dry pavement and be fine, yes there will be a little drag but no its not going to hurt anything, you have added friction all through the system and a little bind, not nearly enough to do any damage, still not a good idea on a routine basis. If you have A-trac or rr diff lock engaged(if you have that)you still wouldnt hurt anything from a mechanical stand point, maybe if you have plastic gears and bike chain. Even if the rear diff was engaged it would be like a welded rear end nothing is going to happen, just chirp chrip chirp. Added stress but enough to hurt anything....no, maybe a little premature wear but the part will "do its time" well before mechanical faliure due to abuse. A-trac is basically modified ABS so no problem there. Your CVs up front wont have a problem dealing with it in 4wd on pavement, only at full lock and sharp turns will you feel it. Think of all the people who cant drive in the snow in NC, they put them in 4wd to get home when they wouldve never spun a tire in 2wd, wont hurt anything in moderation. I did my time at the dealership, dont you think i played with these things when they came out? You have nothing to worry about, they are built very well. Basically dont drive around town in 4wd on a daily basis. There's a FJ and 4wd Toyota run down.
 
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