front wheel bouncing when turning

[Luis696]

front wheels bouncing when turning

I’ve got Explorer 4L SOHC ’97 and when rear wheel slips it engages front wheel drive as well as from this moment my problem starts, I can feel grinding somewhere in front axle and when turning it intensifies and wheels are bouncing causing car bounce as well, it feels scary and as visited ford dealer and have been told few different things I’ve lost myself. I would be more than grateful if someone can help me.

 

[Hartman]

It sounds like you're stuck in 4low.

 

[Luis696]

Do you know how can it be fixed??

 

[ExplorerDMB]

deleted your other post. Please do not double post.

-Drew

 

[Ray Lobato]

Not 4LOW but you are stuck on 4wd.
This is caused by the transfercase. The "brown wire mod" would take care of this, but is not the answer to your solution.
Why is the T-case doing this?
if you disconnect the wires on the front of the T-case, you shouldn't have the problem, and it is in the electronics. If you still have it, then the solienoid is stuck and you will need to have that fixed.

 

[Luis696]

it sounds ok, but as mentioned above usually it drives ok and doesn't cause problems it is happening while driving onto slippery surface and front wheels are engaged or if I move switch on dashboard onto 4x4 high, apart from that it drives ok. Obviously once front wheels are engaged automatically (rear wheels slips) after driving for a while in a normal condition, or if switch to reverse and drive a bit then go to drive - problem disappears, same with the switch, once switch is back in AUTO problem disappears as well.

 

[gijoecam]

Anytime you make a sharp turn on dry pavement or a high-traction surface, the front wheels have to roll farther than the rear wheels. When you are in 4 high and make a sharp turn, the front and rear driveshafts are locked together, and the front wheels can't roll farther than the rears. Driveline bind-up occurs, and you get the wheel hopping.

However, wheel hop and driveline bind-up is NOT a good thing. It puts a tremendous amount of stress on the driveline components and tends to break things.

If shifting back into 4auto makes it stop, then you should not have been in 4 high to begin with. If it's still doing it in 4 auto, then there are other problems.

Read the owner's manual. There is a good section for 4wd novices on the 4x4 operation.

-Joe

 

[glfredrick]

Actually, you have a GEM module issue that will require either re-flashing or replacing the GEM. The GEM is the computer that controls the auto 4-wheel drive function.

You may also have problems with the speed sensors in the front wheels. They give problems when the front wheel bearings (non-rebuildable hubs on the 97) start to fail.

One further issue is changing the T-case oil. I found that it needs to be changed on a regular basis to stop the grabbing and binding as it went into and out of auto 4.

The auto 4 is a great feature when it works correctly -- my wife loved it -- except that our truck, like yours was locked into 4 about half the time, which killed mileage and wore out parts.

BTW, I flashed the GEM once, replaced it once, rebuilt the front hubs once, changed the fluid 4 times, and finally sold the truck because it still did it. I wasn't going to replace the T-case or the GEM again.

I also did some research on this issue and discovered that Ford purchased that T-case from Borg Warner, WITHOUT the recommended (by Borg Warner) computer to control it... BW wanted a computer that factored in EACH wheel speed sensor, while Ford cheaped out and only had front and rear controls. If that T-case had the correct computer, it would be a marvel of engineering. With the Ford computer, it is nothing but a headache that has to be bypassed to give any amount of satisfaction in daily driving...

 

[gijoecam]

once switch is back in AUTO problem disappears as well.

This was why I was thinking it was only doing it in 4wd. In auto, it should not be engaging unless the rear wheels are slipping, at which point, the engagement and disengagement can be kind of abrupt and feel as if it's binding.

-Joe

 

[Luis696]

Thanks, I’ve read manual about 4x4 driving, information that my car doing same with 4x4 high was just because I’ve been looking how to unlock my vehicle from 4x4 high (as the dashboard light doesn’t show it has been switched on) so I’ve tried to force change for 4x4 high and than switch it back off and it works. Anyway, as said 4x4 auto is great feature – if it works – in my case it doesn’t or it does but something else doesn’t, and this is the problem, as I don’t want to you “brown wire mod” as I think it is safer to have it as it should be. Bottom line is while TOD (as far as I’ve read it works) adds more power to front wheels problem occurs and obviously to TOD make any changes car has to be on a slippery surface.

I haven’t check fluid level in T-case and I’m going to do so, hope it will help.

 

[gijoecam]

OK, to narrow down the problem, unplug the transfer case connector and see if it still does it. If it does, it's a transfer case problem. If unplugging it stops the jerking and bucking, then it's a control issue: GEM, TOD relay, shaft speed sensor, etc. Any Ford dealership (well, state-side anyways.... don't know about London) should be able to connect the tester and view the GEM inputs and outputs to pinpoint the problem in a few minutes.

-Joe

 

[Luis696]

Thanks  I’ve been with ford two days ago, they have tested it and what they said is that they are not sure but suspecting that it is caused by diff, and that GEM is good, I don’t believe they have tested one, I think what have they done is they have checked that lights are changing while switching and it means GEM works fine.
The only problem with ford here in UK is that they not selling any 4x4s apart from Ranger, so they are not to much alike 4x4 testers if you know what I mean and this is why I have started to look for help somewhere else.

 

[Ray Lobato]

Let's clear a few things up here then we will see if you really have a problem.

1) You must understand that in 4wd, on a hard surface and in a turn, your outer wheel WILL bounce or chirp. That is because the differential is trying to turn both wheels at the same rate and the outer wheel is really rotating faster than the inner tire. This is called binding and is normal. This is why you can't drive in 4wd in hard surfaces.
2) When you encounter wet conditions and the rear wheels start to slip, the GEM via the ABS sensors will put the truck into 4wd. This is usually transparant, but you could feel a jolt like feeling if the slipping is signifficant. This is also normal.
Anytime you are in 4wd and on a hard surface and are turning, binding in the axels will happen, and chirping or tire bouncing is the result.

Now please tell me if your problem exsists anytime other then these conditions

 

[Luis696]

I will re4ply on one with one simple thing, I have my car lifted today, and wheels are bouncing even without any weight on them, and bouncing when turn only, so to explain it even more once wheels are rotating (car lifted, wheels doesn’t touch ground) while turning steering wheel and reaching certain point wheels starting to jog, bounce or dribble (something like that). I don’t know which word is the best.

 

[gijoecam]

by bounce, do you mean that they move up and down, or do you mean that they are not rotating smoothly?

-Joe

 

[Luis696]

I would say they are moving up and down, but once they are locked (steering wheel turn left or right) it is hard to turn them with bare hands as well.

 

[Ray Lobato]

Sounds like you are saying that once the tire reaches the end of it's mechanical stop that it is bouncing. Well It will do that, once it hits the mechanical end. The steering pump is trying to overcome the mechanical stop and is bumping against it. It will do that. What you don't want is for the tires to do that before that mechanical stop. Does it do that (bounce or rattle) before the mechanical stop?

 

[gijoecam]

I'm so confused. :dunno

I don't have the foggiest idea what the thing is doing and I'm out of questions to ask.

Any possibility you can video-tape the vehicle doing what you're describing? I think that's the only thing that's going to fully explain what it's doing.....

-Joe

 

[Luis696]

yes, once max turned left or right it starting to bounce (move up and down) and you can see it and feel it while driving, the slower car is going the more you can feel it, in a critical moments whole front of a car is moving up and down (you know like those mexican cars with pneumatical suspension) and whole time I can feel and hear grinding noise somewhere in front of pedals.

 

[Skibug]

Ok it sounds like you have the problem of a bad power steering pump or rack. My rack is going out and when I turn the wheels, I get a vibration in the whole truck. This vibration occurs mostly at low speeds while turning because at low speeds the power steering system has more strain on the system at low turning speeds.

Do this test and tell me what happens. Find some sand and come to a complete stop. Or simply jack up the front end. Turn your wheels back and forth while at a complete stop. If in sand and your truck begins to shudder/vibrate then either your power steering pump or your rack and pinion setup is going bad. The shudder should be more noticeable while your truck is on the ground compared to when your truck is lifted off the ground due to the resistance put on the power steering system. This would also explain the experince you have of when you jacked it up and turn the wheels all the way to lock and the vibration occured. When the wheels are turned all the way to the steering stops and held there, strain is being put on the power steering system.

See this post for a little more info.

http://www.explorerforum.com/forums/showthread.php?t=150816

I don't think your problem is driveline related at all.