what causes front binding in 4x4?

[purpony]

I was wondering, what causes the front end binding when in 4x4 and taking a corner in say a 9 ranger/ttb front end. Is it due to the front axles having u-joints or the t-case itself?

thanks

 

[Mutant Pony]

If your talking about the jerking from side to side when you turn really sharp in 4wd then yeah, it is the u-joints. All 4x4s with u-joint style axle joints do that. When you turn that sharp in 4wd you are on the verge of breaking an axle or u-joint.

 

[metalmacguyver]

its because there is no center differential. when you turn, the front axle has to go further than the rear. but they have to rotate the same number of times. the result it that it has to slip. but before it actually slips the suspention and drive train load up and then release when it slips. that gives the lurching feeling when turning sharply. in 4x4

 

[Mutant Pony]

yeah that too!

 

[Jspafford]

It's not good on any part of the truck... Refrain from doing it.

When turning the inner wheels turn less revolutions than the outside on both axles. There is no way for the difference to be released other than the winding up and jerking you fell.

 

[purpony]

reason i was asking is, thinking of using an AWD t-case in my 92 ranger with the ttb front end..... I have been reading that with the AWD t-case i would get less binding in the front with u-joints then a 4x4 t-case......??

 

[Jspafford]

AWD is made to be run all the time. It doesn't shut off.

4WD is for part time use.

 

[purpony]

i am swapping a 97 explorer v8 driveline into my 92. I am trying to decide if i should us an aod with a AA and stock 4x4 t-case or use the 4r70w with a baumann controller and the awd t-case. I love awd and im sure it would help out alot with the light weigt ranger rearend as far as traction goes. I know of one guy running the awd in a 94 with the ttb/u-joint front end and so far has logged 40,000 miles. I was thinking about doing the same, but was wondering will the front end be binding everytime i take a corner. Then someone said that the u-joints dont really cause the binding, its the 4x4 t-case that does??

 

[Jspafford]

Well that's a good question. I don't know of any all wheel drive vehicle that uses U-joint axles. They all use CV joints now.

I don't see why a U-joint would be much different other than making some noises at full lock turns.

An AWD case has provisions to let things slip so making turns should not be a problem.

 

[MAKG]

It's not good on any part of the truck... Refrain from doing it.

When turning the inner wheels turn less revolutions than the outside on both axles. There is no way for the difference to be released other than the winding up and jerking you fell.

It's not the side to side tracking difference. That's what front and rear differentials are for.

It's that you only turn the front wheels in a turn. This means both front wheels travel over a longer distance during a turn than the corresponding rear wheels. It's the front/rear windup that causes binding. AWD vehicles work around this by either having a center differential, a viscous coupling between front and rear, or some kind of fancy electronically controlled clutches that release during turns.

 

[TireIron]

So in effect you can run the AWD t-case and not have the binding that the 4x4 t-case has when turning (and you shouldn't use the 4x4 t-case on pavement anyway) So if this is going to be a street driven vehile all the time then the AWD t-case would be a blast with the 5.0L. If it is gonna be an offroader then you may want to stick with a 4x4 t-case and just live with only having 2wd on the streets.

Hopefully if you use the AWD t-case you have the D35 in the front and not the D28 with that 5.0L heh.

 

[purpony]

ya, its a street driven daily driver and yes, its got the D35 up front.

I had an AWD V8 Supercharged Explorer... that was a blast and miss the awd.

 

[tanbuddy]

Dude, around sharp turns its gonna have that lurch lurch feeling even with the awd t case. I ran my truck in front wheel drive a few times (rear driveshaft was in my bed in 2 pieces) and it lurched around turns pretty bad yet. I would look at a old (70s) full time 4x4 in a full size truck to see how they got it to work.

 

[4x4junkie]

Well that's a good question. I don't know of any all wheel drive vehicle that uses U-joint axles. They all use CV joints now.

Yeah, virtually every 4WD truck had available AWD and u-joint frontends at some point during the '70s (the Jeep Cherokee took it well past the mid '90s).

You'll be fine with the AWD case and u-joint frontend. Anything the u-joints cause will be very minor (especially with an auto transmission), and will probably only be noticeable with the wheel cranked at or near full-lock (being in FWD is not the same as AWD either, the u-joints lurching will actually be split somewhat by the AWD case, lessening their effect).

One thing unique to the TTB frontend you'll probably want to make sure of though, that the center u-joint is perfectly flat at ride height. If the suspension sits too high or low, it might impart a little bit of it's own effect while going straight (some info about TTB ride height here).

 

[Jspafford]

Well I guess I should have said, "Every vehicle with AWD I've seen"

I wasn't even around in the 70's.

And the part you didn't quote I told him he would be fine with a U-joint front end.