Terrible front axle binding w/ 4X4 engaged

[JPM]

In a straight line everything is SAT ( except the MPG's go down the crapper!) but turning sharp , this truck has the worst binding , lurching that I have ever seen. My ole "50 Power Wagon was better! Is this normal for these?

 

[SRadke]

They are pretty long and when you turn sharp the front end has to travel way farther than the back. Any kind of traction and you're in for a ride. It's normal.



-Scott

 

[nickleinonen]

part time 4wd system. only to be used on slippery surfaces. not ever on dry pavement

 

[JSchutz]

In a sharp turn the inside tire is treaveling a much shorter distance than the outside tire and with everything locked up in 4wd "lurching" is inevitable. That's why it's not good to be in 4wd on dry pavement--tough on tires and drivetrain.



BTW I ran 360 miles on the interstate in 4wd on ice/chopped snow several weeks ago and got 19. 8 mpg. I'm sure that driving 50 mph is the reason. Jeff

 

[DLoughery]

Originally posted by JPM

In a straight line everything is SAT ( except the MPG's go down the crapper!) but turning sharp , this truck has the worst binding , lurching that I have ever seen. My ole "50 Power Wagon was better! Is this normal for these?

Yes that's normal. With mine I can even feel some binding on slippery surfaces. I only engage 4 wheel drive when there are excessive amounts of wheel slippage. With the posi rear end it is rare that I ever have to go to 4X4.

 

[DocDetonancour]

I use 4 x 4 a lot this time of year and see little, if any, loss of mpg with the CTD.

 

[Mopar_Mudder]

Originally posted by JPM

In a straight line everything is SAT ( except the MPG's go down the crapper!) but turning sharp , this truck has the worst binding , lurching that I have ever seen. My ole "50 Power Wagon was better! Is this normal for these?

2 things, your new truck will turn twice as sharp as the old power wagon, and the new truck probably weighs twice as much on the front axle too.



My 83 doesn't hump up as bad but it also take a small field to trun it around it. Nice thing about elect 4x4, got to make real sharp corner just turn it off for a second.

 

[KBennett]

I noticed this last night when I was treating the family to some "doughnuts" in the local shopping center's snow packed parking lot.

I had to be careful how hard I turned the wheel or you could hear the binding in the front end.

It is the front universal joints and not the tires that are binding. I used to have this problem with my '67 International Travelall when I was trying to make a hard turn while plowing. My last 3 trucks were IFS so I had forgot about it, they only bound up when on dry pavement.



Most of the time when I have it in 4WD it is slick out so if I just blip the throttle the whole truck turns

 

[JPM]

I think that with the Gen. 3 trucks,Dodge decreased the turning circle to compete . But they didn't change the front axle components to cope ,they just allowed the fronts to turn more. Causing more binding than I have experienced in 30 years of driving 4X4's. Even on snow I cannot back up into a parking space without truck the bucking.

 

[SRadke]

The bind is traction related not component related. Remember, all those parts are turning all the time in the 3g's, there is no axle disconnect or hubs. If they did bind they would do it 4wd or not.



-Scott

 

[ceastmen]

Originally posted by JSchutz

In a sharp turn the inside tire is treaveling a much shorter distance than the outside tire and with everything locked up in 4wd "lurching" is inevitable. That's why it's not good to be in 4wd on dry pavement--tough on tires and drivetrain...

No flames intended,... just info!



The "bind effect" is due to the difference in distance traveled by the front and rear tires (front driveshaft vs. rear driveshaft), it's not the an inside vs. outside tire issue. In a turn the front driveshaft turns fewer times versus distance traveled than the rear driveshaft. The rear axle does not track the front. This can be seen if you make a shrp turn in snoe, you will see 4 paths in the snow, indicating the rear axle is not tracking the front.



I'll clarify further. When you put your truck in 4WD you are intentionally locking the front and rear driveshaft together, this is done in the transfercase. Now, if the front drive shaft turns fewer times per distance traveled as compared to the rear driveshaft, both the shafts will twist creating severe torsion (like winding up a spring) then they will unload when the built up torsion exceeds the traction limit of one of the tires,... then the process repeats if you continue in a turn on dry pavement and it lurches. This effect is more severe the longer the truck. Remember 4WD does not lock the inside tire to the outside tire, only a locker or spool will do that.

 

[Mopar_Mudder]

Originally posted by ceastmen

No flames intended,... just info!



The "bind effect" is due to the difference in distance traveled by the front and rear tires (front driveshaft vs. rear driveshaft), it's not the an inside vs. outside tire issue. In a turn the front driveshaft turns fewer times versus distance traveled than the rear driveshaft. The rear axle does not track the front. This can be seen if you make a shrp turn in snoe, you will see 4 paths in the snow, indicating the rear axle is not tracking the front.



I'll clarify further. When you put your truck in 4WD you are intentionally locking the front and rear driveshaft together, this is done in the transfercase. Now, if the front drive shaft turns fewer times per distance traveled as compared to the rear driveshaft, both the shafts will twist creating severe torsion (like winding up a spring) then they will unload when the built up torsion exceeds the traction limit of one of the tires,... then the process repeats if you continue in a turn on dry pavement and it lurches. This effect is more severe the longer the truck. Remember 4WD does not lock the inside tire to the outside tire, only a locker or spool will do that.

He is correct, but also the sharper you turn the worse the effect is, so you notice it more on the newer trucks with the sharper turning radius compared to the old timers



Drive a truck with different gear ratio in the front and back once, then you will really know what bind up is, LOL

 

[ceastmen]

Originally posted by SRadke

The bind is traction related not component related. Remember, all those parts are turning all the time in the 3g's, there is no axle disconnect or hubs. If they did bind they would do it 4wd or not.



-Scott

Once again No flames intended,... Just info!



In the 3rd gens, when in 2wd, the front and rear drive shafts are free to turn independently of each other, no binding.



The front and rear differential allow the inside and outside tires to turn independently as well,... so there should not be any binding between inner and outer tires, hence the name "differential".



Altogether now, there should be no binding as far as the driveline is concerned UNLESS DC made the turning radius tight enough to begin binding the front outer U-joints (located in the steering knuckle). U-joints can only handle so much angle before they begin following an elliptical orbit centered on the axis of the axle in which they are constrained.

 

[Mopar_Mudder]

Originally posted by ceastmen

No flames intended,... just info!



4WD does not lock the inside tire to the outside tire, only a locker or spool will do that.

And the amazing thing it that with a spool you will get no bind at all, but that is do to the fact that you wont beable to turn a corner in the first place

 

[ceastmen]

Originally posted by Mopar_Mudder

He is correct, but also the sharper you turn the worse the effect is, so you notice it more on the newer trucks with the sharper turning radius compared to the old timers



Drive a truck with different gear ratio in the front and back once, then you will really know what bind up is, LOL

Couldn't have said it better myself! Exactly!

 

[Mopar_Mudder]

Sorry this is a little off subject, but it is about bind up and it has to do with Ford's so I just gotta tell it.



Buddy has an old Ford mudder truck that had a Dana 44 front in it. Well you fond a Dana 60 front pretty cheap so he bought it. Well AFTER he got it home he realized that the axle was sitting up side down when he bought it and it was actually a Chevy front so the pumking was on the wrong side. OK that is where it starts to gets interesting.



When after some deep thought the figure that the Ford with the divorsed trans case and the real long shaft they have on the front they can just put the axle in their and run the drive shaft side way to it. Well in truth the drive shaft will run like that with out too much problem.



So they put it all together and get it running, ok drop it in gear and stand on it and the truck starts bucking and humping up in the middle real violently. Ya see they forgot the fact that the Chevy uses a standard rotation front axle the the Ford uses a reverse rotatio. So while the rear axle was trying to drive forward the front axle was trying to go back wards, or vise versa when you put the truck in reverse.



Ok so it is Friday and we HAVE to go mudding tomarrow they say. So a great fix is found, flip the back axle upside down so you are reversing its rotaion. This does work, but now forward is reverse and reverse is forward. So he had 1 gear forward (reverse) and 3 gears back wards (automatic). That was the fastes dam truck I ever seen going backwards. LOL



No that my friends is "REAL" drive line bind up to the extreme.....

 

[rbattelle]

Originally posted by ceastmen



The "bind effect" is due to the difference in distance traveled by the front and rear tires (front driveshaft vs. rear driveshaft), it's not the an inside vs. outside tire issue. In a turn the front driveshaft turns fewer times versus distance traveled than the rear driveshaft. The rear axle does not track the front. This can be seen if you make a shrp turn in snoe, you will see 4 paths in the snow, indicating the rear axle is not tracking the front.



I'll clarify further. When you put your truck in 4WD you are intentionally locking the front and rear driveshaft together, this is done in the transfercase. Now, if the front drive shaft turns fewer times per distance traveled as compared to the rear driveshaft, both the shafts will twist creating severe torsion (like winding up a spring) then they will unload when the built up torsion exceeds the traction limit of one of the tires,... then the process repeats if you continue in a turn on dry pavement and it lurches. This effect is more severe the longer the truck. Remember 4WD does not lock the inside tire to the outside tire, only a locker or spool will do that.

This is a great post. Many thanks, ceastmen! I learned something from it. I have always thought it was the outer U-joints that were binding on tight turns.



BTW, my truck still tends to bind a bit when on slippery pavement. I've learned to be careful how sharp I turn.

 

[Joseph Donnelly]

The stub shafts speed up and slow down when the u joint is at an angle, more so when the angle is steep. This effect makes for more bucking, and is also hard on u joints. Same effect in driveshafts. When one u joint is at a different angle than the other (common with lift kits), one end of the driveshaft is trying to turn differently from the other, and parts suffer.

 

[jungledave]

one more thing to add , when a u-joint is at a sharp angle the velocity, I am sure i misspelled that, is not constant. It looks very much like a sine wave in that as it rotates it takes the same amount of time to complete one revolution as when the wheel is straight but it changes speed as it rotates. This can be felt as the jumping that you feel as the sharply angeled u-joint changes speed very dramatically up and down as it completes just one rotation. This in conjunction with the front end traveling more distance than the rear end of the truck. And as mentioned earlier the front end of these trucks are very heavy and don't slide as much as the lighter trucks. I Had a salesman try and tell me that the 04 turned sharper than the 02 I drove in with. I easily turned a full circle in the dealer lot whith my 02 that the 04 couldn't do. The salesman didn't know what to think or say. It was really funny.