Control Trac 4WD Questions and Problems

[64hala]

I have a question regarding my control trac 4WD. My first question is that when I read my Ford owners manual it makes it seem that I can run the explorer in 4WD whenever I choose and the car will figure out when it is actually needed. Now I know my orginial 91 and 92 explorers were not this way. I figure it's kind of like when you choose full time 4wd vs. part time 4wd in a jeep cherokee? So my back tires are shot and the car is sliding around all over. So in the rain I put in 4WD. At first the 4WD light didn't pop on after I turned the switch. So then I nudged the switch and it kicked in. I could feel the difference and I was getting a sort of moan when slowing down, so I new the front end was turning. When I slamed the gas down from a stop light, I didn't get my usual rain induced wheel spin. The only thing is that while it was in the car just sounded unhappy about the whole experience. Now when the Jeep is in full time 4wd you almost don't even know it's in. This leads me to think that the ford system is not made for dry pavement, rainy surfaces or freeway driving. I am assuming control trac is just like the old system that was used only in snow and such. Well then as I continued driving I noticed the 4WD light on the dash went out, but the car still felt like it was in 4WD. Does the light come on and off while driving? Does it just turn on when the car senses that it needs to be in 4WD and it has engaged? Needless to say the light never came back on and before I got home I just put it back in 2WD which made the car sound much happier. So is my control trac broken? Please email me at brianwinchell@aol.com for advice. I appreciate it. I am really confused and don't want to roll into my Ford dealership and drop another couple grand to fix the problem. True then again driving in 2WD all winter when it snows will blow.

Thanks

 

[Mikes95XLT]

Post replys here so we can all read about it. I have control trac too, and would like to know what the thoughts are too....

 

[jimbo74]

does your 4x4 switch have 3 positions of 2wd, 4x4 and 4x4 lo? or does it have the newer version with no option for 2wd?

 

[Mbrooks420]

Its a 1996. He should nave 2high/4 auto/4low. I wouldn't run 4auto in the rain. I'd buy some good tires and not worry about it. The light SHOULD NOT go off and on. The system is automatic 4 wheel drive. It sends minimal power to the front, until it sences slipping from the rear.

 

[TPLYNCH]

You should be able to run in Auto in the rain w/o problems. The system should is designed to apply power to the front wheels in increments when it detects speed differences between the front and rear. If one of your speed sensors is dirty/malfuntioning, it will keep the system engaged when it shouldn't be. What you describe sound like this is the case. You can remove the speed sensors from the t/f case and clean them. They are small magnets. Run a search for speed sensor and for control trac for threads describing how to fix as well as detailed explanations about how the control trac works.

 

[64hala]

My 4WD switch does have 3 positions of 2wd, 4x4 and 4x4 lo? I will check this site for info on cleaning my speed sensors because it was said that a dirty/malfuntioning sesnor, it will keep the system engaged when it shouldn't be.

But should my 4WD light be going on and off in my dash while I am driving? Is that normal?

Much thanks,
Brian

 

[daniel cauchon]

No my friend you light should be on and stay on until you switch it back to 2wd.

 

[Opera House]

If your switch doesn't say auto

you won't have speed sensors turning it off and on. When did the light first start flashing? Was it after you tried to go into 4WD? When the position switch contacts get dirty or the motor fails to work, the lights will flash. My 97 was low on fluid due to a bad rear seal. I had just bought it and the last owner even bought a brand new shift assembly but couldn't get it to work. Put new fluid in and disconnected the battery to reset the computer. No problems for a year now. I have also cleaned the motor on my 92.

 

[64hala]

The 4WD light doesn't flash, it just shuts off. I think I am going to crawl under the car and look at the rear speed sesnor. If that doesn't work I will get the transfer case fluid changed and discontect the battery for a while.

 

[Robert]

As others have said, your '96 has 2WD, 4x4 Auto, and 4x4 Low. You can run Auto in the rain or even on dry pavement. Ford tested the system for 2 years on the '95 & '96 before making the Auto mode the standard mode on '97-'01s. Ford got enough supporting data that the Auto mode was OK to use under all conditions so they did away with the 2WD mode and made Auto standard. If your lights shut off while you are still in Auto, then something in your system isn't working correctly. The light should stay on until you select 2WD.

 

[64hala]

So I cleaned the rear altoid shaft speed sensor and disconnected the battery for an hour to see if that helped. Well when I put everything back together and drove the car everything was fine in 2WD. I switched the car into 4WD and nothing happened. In about thirty seconds the light 4WD light came on and the car was going in 4WD. There was also a slight growl from the front end and the car felt like it was in more of a 4WD high than an auto mode. Well then the lights 4WD light and 4WD Low light started to flash like I have been reading about. That didn't happen last night. I kept driving and all lights shut off. The car still wined and felt in 4WD. Then the lights flashed again about thirty seconds later. When I stopped to make a right turn the car felt as if it didn't want to move so well and started making a hard growl from the front. That's when I switched back to 2WD and then it popped out and everything felt fine again. Then as I was driving in 2WD the 4WD light and 4WD Low light started to flash. So does it still sounds like replacing the front and rear altoid shaft speed sensors will do the trick? Should I get the transfer case fluid changed? I came home and disconnected the battery again. Before this incident the car has never flashed 4WD light and 4WD Low while driving in 2WD. I hope by clearing the memory the car won't do it anymore, because then it will be a constant reminder that I may be destined to only own a 2WD explorer.

 

[Jason_25]

First things first. Change your transfer case fluid. It is very easy to do. Also, check and make sure that your front diff has the correct amount of fluid in them. Early 2nd gens have a bad habit of "puking" fluid from the vent tube when going in reverse due to the design of the gear teeth.

Once you have done that, reset the computer, try out the 4x4, then see if the lights flash. If they do, it's time for new speed sensors.

 

[dogfriend]

You might want to check this thread :

Dead Link Removed

Mikefox posted some links in this thread which describe the operation and the schematics for the 95-96 Control Trac system.

Robert is correct; if your system is working properly, you can use 4Auto on dry pavement if you want to. The flashing 4wd lights indicate that the GEM is detecting a malfunction with the 4wd system. It could be the driveshaft sensors or it could be something else in the system which is causing the problem.

 

[Mbrooks420]

In my 1996 my 4auto doesn't make hardly any noise at all. Maybe it thinks the back tires are spinning and directing most of the power to the front. My ex turns like its in 2wd also.

 

[kenr]

Just fixed the same problem on my 97 XLT. Turned out the rear sensor was bad. Pretty much the same symptoms, front engaged always, until lights started flashing, at which point the 4x4 is disabled until you turn the truck off and restart. Pretty easy to fix, part was 30-something bucks delivered from fordpartsnetwork.com. Took about half an hour to change.

 

[Robert]

I have never been able to confirm it, but I do remember reading posts from people with '95 & '96 Explorers that when their 4x4 lights were flashing, the system resorted to 4x4 High. In other words the front wheels were locked to the rear wheels which would account for the noises and hard steering. On '97 and up though when the GEM detects a problem and flashes the 4x4 lights, it resorts to a 2WD mode, disabling the 4x4 operation. When your GEM detects a prolem it is normal for your lights to flash for several minutes and then stop for several minutes and then start flashing again. It does that so that you can read the LFC (lamp flash count). If it didn't have a break between flashes, all you would see is a flashing light that wouldn't provide any diagnostics as to the source. Your lights are flashing a code to you. Count the flashes starting with the first one. You'll have a slight pause as it flashes the second digit, then it will repeat again. A faulty speed sensor can cause the symptoms you described.

 

[64hala]

Ok update time on my 96 control trac. This morning I bought a new rear speed sensor and installed it. Once installed I put the car in 4WD Auto and it acted the same way as before but the lights didn't flash. I may have not left the it in 4WD long enough to flash but the front end sounded bad so I switched it back to 2WD and the car ran fine. So then I went and had my front and read differential fluid changed and my transfer case fluid changed (they said the transfer case was low on fluid). When I got home I stopped and put the car in 4WD Auto. For the first time the 4WD light popped on right away, not the usual 30 second wait. Everything sounded fine until I started to slow down and then i got a moan. Then I tried to turn and it feels like the front wheels are still locked with the backs. I got bad noises and popping from the front end. So then I stopped and put the car into 4WD low. The car acted completling like it should. Once back into 4WD Auto it started acting up again. During this whole time I never got the flashing lights.

So what should I do now? Should I disconnect the battery and try again the senario again?

Should I go to the dealer and have them look at it? I think all things are leading to either the front speed sensor is bad or I somehow messed up the install on the new rear sensor and it's bad again also. Please advice if you aren't all tired of hearing about this.

Thanks again.

 

[tenikiwon]

Speed Sensors

Where are the speed sensors located?

How are they cleaned?

How Many are there?

Pics would be nice.

 

[dogfriend]

Re: Speed Sensors

Originally posted by tenikiwon
Where are the speed sensors located?

How are they cleaned?

How Many are there?

Pics would be nice.

http://home.attbi.com/~gordongroupie24/control_trac_transfer_case.jpg

The link above is to the exploded drawing of the transfer case. Item 32 is the rear driveshaft speed sensor. Item 53 is the front driveshaft speed sensor. There are two of them. They are both located on the rear side of the transfer case. The rear driveshaft sensor is located just above the fill plug. The front driveshaft sensor is under the shift motor, so the shift motor must be removed first to access it for removal.

Both driveshaft sensors are Hall effect devices. This means that they generate a voltage in response to a changing magnetic field. The magnet is part of the sensor. The field is disturbed by exciter ring(s) which is mounted on the rear driveshaft and front driveshaft(s). The voltage is sent to the GEM to determine the shaft speed.

You would clean them by removing them from the case and wiping off any metal debris which might be stuck to the magnet. If you have a lot of debris, I would recommend draining the transfer case and replacing the ATF to get as much metal out as possible. There is a magnet inside the t-case(to catch stray particles), but you have to take the case apart to clean it off.

 

[64hala]

So I went to my local Lincoln Mercury Dealer to have them look at the control trac on my car. They said the first thing that I need to do is get matching tires on the front and the back. They were two different brands and they said if the tires aren't the same brand that it can throw of the control trac when it's in auto mode. Well needless to say I got the tires and well it still doesn't work correctly. Going straight at about 10 MPH everything seems fine, but as soon as I turn the wheel a little I get popping noises and resistance while attempting to turn. True none of the 4WD lights have blinked, so I don't even know if it would be the front speed sensor now. The lincoln serivce manager seemed dumfounded when I mentioned bad sensors, not sure which service station I should turn to next.