Control Trac? Thumb up or down?

[95EXP4.0]

I also have the contral trac system on my 95 xlt, i can switch it from 2wd to 4wd. I can say I also have experienced a thud coming from the front differential coming from dead stops or while accelerating I thought it was me going crazy! I was also wondering if anyone else out there has tried this.....I noticed it doesn't move on it's own idle if I have it in 4x4 being engaged in drive. Obviously in 2wd it rolls without effort.

 

[yob_yeknom]

This 'thud' you are speaking of.... Is it a hard, harsh thud or a small, light one? Are you giving it a lot of gas while accelerating from a stop, or just driving normally? Also, is this on dry pavement or something else?

Small to medium 'thuds' can be expected under heavy accelleration from a stop on dry pavement. The system senses heavy accelleration and begins sending some power to the front to prevent it from beginning to slip. Kind of like a smart thinking system.

Harsh 'thuds' can be felt sometimes while on snowy and icy roads. If the front wheels hit a dry spot on the pavement while the back is slipping, it can grab the dry pavement pretty hard.

As for the not pulling itself at idle in 4wd auto mode, in theory being in 4wd auto should not affect anything. It should be able to pull itself just as it was in 2wd. I'd have to go out and test mine though to make sure. You know how things should work in theory sometimes, but don't in actuality.

 

[Pack]

You need to have the computer...

reprogramed. My '98 did the same thing until I brought it to the dealer to have it fixed. They reprogramed the computer and the thud went away. The thud is the front drivetrain being activated on dry pavement. Now, even under full throttle acceleration, there is no thud. BTW- I tried replacing the sensors in the transfer case that tell the computer to activate 4WD, before I brought it in to the dealer, but that was a waste of a C-note.

Hope this helps. The dealer charged me $180 to fix the computer.

 

[95EXP4.0]

If you had to get your computer reprogrammed don't you think that would be a warranty/defect issue though? I know the dealer is money hungry but sometimes they actually help.

 

[95EXP4.0]

I looked into it more today and tried to engage it from nuetral to reverse then it locks in pretty smooth back and forth. But when I tried to pull in the garage and when I turn the wheels is where I see all the problems starting. It seems when I'm in 4x4 high I feel big time resistance when I try to accelerate and I'll hear the differential or the t/c make a loud "boom" and it will do it more than once if I keep accelerating, kinda' scary if you ask me. I tried the same thing with 4x4 low doesn't really seem to be doing it while turning like when I'm in "high" but I didn't really try it too much. When I finally disengage it from low I hear that nasty "boom" once again when I get it into neutral please don't tell me this is normal!?

 

[rustytr]

I give it a thumbs up, I like because it disengages at 15 mph.

 

[yob_yeknom]

95EXP4.0

Check your other thread for my answers.

 

[Robert]

95EXP4.0 -- Unless your garage has a gravel floor, I wouldn't recommend doing that again. The thud, clunk, binding you feel and hear is normal, right before expensive parts start to break. You need to be on a loose surface to turn when you are locked in 4x4 high/low. Eventually you'll break something.

 

[01EB5.0]

Originally posted by Robert
95EXP4.0 -- Unless your garage has a gravel floor, I wouldn't recommend doing that again. The thud, clunk, binding you feel and hear is normal, right before expensive parts start to break. You need to be on a loose surface to turn when you are locked in 4x4 high/low. Eventually you'll break something.

On the 95 and 96 explorer, the front axle can be put in 4X4 AUTO mode in any road condition...there is no "locked 4WD HIGH" on this truck..... and if it is working correctly should not bind or clunk when drivin in this setting. the only time it should clunk is upon heavy acceleration and you should feel the front axle pull. The system clunks a lot (and it sounds bad) but it is only the front clutches pulsating. if it does that on dry pavement under normal acceleration you havea problem. Also on the 95 and 96 the 4WD LOW setting is the setting that can not be used on hard pavement. I mean pulling intot he garage is ok, but don;t do a ton of driving like that because it stresses everything up front. my 4WD LOW clunck when engauging and disengauging and it is "normal" it is just everything locking in.
To help ensure that everything up front continues to work correctly, you should use your 4WD LOW setting once a month for a mile or so...just to get the lube flowing up front. I just find a gravel parking low or a dirt road to tear around on.
If the 4WD or 4WD LOW lights do not illuminate or if they flash, then you know you have a problem. if not it's all good usually.

 

[Robert]

Yep, I saw the 4x4 High and didn't pay attention to the year. It isn't a locked high, it is 4x4 auto and is safe to turn into the garage in that mode.

 

[yob_yeknom]

Originally posted by 95XLT
On the 95 and 96 explorer, the front axle can be put in 4X4 AUTO mode in any road condition...there is no "locked 4WD HIGH" on this truck.....

That is also what I thought, but apparently this guy and also Karol (who has a '96) both don't have the auto option. They have actual 4 high. There's another thread regarding this somewhere. How? Beats the heck out of me. Just when you think you know something...

 

['96explorereddiebauer]

They must've modified it because my '96 doesn't have 4-by high.

 

[Robert]

Originally posted by yob_yeknom
That is also what I thought, but apparently this guy and also Karol (who has a '96) both don't have the auto option. They have actual 4 high. There's another thread regarding this somewhere. How? Beats the heck out of me. Just when you think you know something...

Until I've seen actual proof that goes against everything I have read for the last 5 years, I will continue to believe it has 2WD, Auto High, and 4x4 Low. Every review of the '95/'96 Explorers rave about the new Control-Trac transfercase that lets you run in 4x4 Auto for situations that warrant it. None have ever said a different transfercase was available to give a true 4x4 high. Even my '96 Explorer brochure makes no mention of a 4x4 high mode, but they do rave about the Auto setting.

 

[IAmTodd]

Here's all the info i have on the control trac:
95-96 Options- 2wd, 4 auto, 4 lo with vaccum disconnect
4 auto can be left on full time with no damage
95% of torque to back 5% to front, when wheel slipage accurs, torque is sent in either 5 or 10% "spurts" until traction is regained then is reversed.

97-^ options 4 auto, 4 hi, 4 lo w/o vaccum disconnect
vaccum disconnect was not need becuz of no 2wd mode
2wd mode swapped out for 4 high
other than that, that is the basics.

I have mixed feelings with the control trac, my family has a 95 and 02 x, one with each different version of control trac. I think ford should've put all 4 options on but that'd be too easy. With the 95 i haven't had to much experience with the Control Trac, but i'm very disapointed with the 02. I was coming up a slight snow covered hill when i could hear the 4wd kick in. Next thing i know the rear end starts to kick out and i'm like crap! so i stop(on a snow covered hill ) Engage 4high and it climbed right up. I like a normal transfer case better, but i'll just have to live with what i have

 

[Nate1]

I can basically sit on loose dirt in my '99 X-Sport (SOHC) and floor it (granted, I have new tire)... I CANNOT induce wheelspin. It's crazy, control trac works awsome from everything that I can tell, the only thing it sucks for is doing doughtnuts... which I absolutly cannot do unless its on wet/muddy grass... and then its only like 2-3' of slip. I have 4.10 open diffs... on A/T tires.

I wanted to try the 'yellow wire disconnect' trick for turning off control trac when I want to do some doughnuts..... but it sounds like w/o vaccum disconnect you could potentially do some damage... or does it still apply that ~4% torque to the front and just never sense the back to give the front more power?

Anyways, nothing but good about control trac.... other than the occasional clunk and the inability to do doughtnuts.... both of which I can deal with.

Just my 2¢
------Nate

 

[JasonF]

I love control trac on my 96. I much prefer this to a conventional transfer case because I can put it in 4wd auto when driving on wet roads and not get lousy gas mileage, yet if I need to turn up a wet a hill from a stop I don't have to worry about spinning because of the weight transfer off the inside rear tire. Auto4wd kicks in smoothly and just pulls right up. I also like having the 2wd option for the summer, I know what will break the rears loose. Its fun driving a conventional 2wd vehicle that doesn't ruin all your fun if you want to spin em once in a great while.
Like others have said, if you are going slowly and hit it and the rears break loose real quick, you will feel a bit of a thud as the fronts come on line quickly. I don't know how they could fix this, if the fronts came on line slowly it would be awkward. As long as you don't nail it at low speed, it pulls in nice and smooth. Like tonight I was backing up a hill to park and was on packed snow/slush and I was spinning in 2wd. I stopped, flipped into auto, tried to back up again and heard the rears just start to spin, felt a slight clunk and away I went. I love my truck

For the gurus out there, what exactly is the difference in the front end between auto and low? Does auto 4wd use an open diff in the front, and with low it is locked? I don't understand why auto can work without having the hubs lock, but low needs to lock them up.

Jason

 

[Nate1]

I'm no expert, but I think that when you clutch (?) or however it transfers the power in 4x4Auto, you are giving minimal power to the front, so you therefore don't bind up. When you are in 4x4Low your front and rear wheels must spin at exactly the same speed, so if your tires are unevenly worn or anything of the sort, you will bind. I think it has to do with the power transfer. I mean, you really would never notice it because if you are making 4x4Auto work on a turn, its cuz your rear wheels are spinning, so you wouldnt even get binding, since they are already slipping.

I dunno if I'm right, but that is always what I've thought.

 

[NedFlanders]

Originally posted by JasonF
For the gurus out there, what exactly is the difference in the front end between auto and low? Does auto 4wd use an open diff in the front, and with low it is locked? I don't understand why auto can work without having the hubs lock, but low needs to lock them up.

Jason

Okay.. I'm not a guru eighter, but I've read quite a bit about the control track.. The front end of the '95-'96 models(the ones with the 2wd option) disconnects one of your frontwheels from the frontdiff with the wacum-disconnecter, while the other one is always connected, not to the whole drivetrain, just to the frontdiff. That's in 2wd. In 4auto and 4low, the second frontwheel is also connected to the frontdiff. The difference between auto and low sits in the magnetic clutch connecting the front diff to the transfercase. In 4low(and 4high on the newer models) it's totally locked together, so that both of the frontwheels will have the same totalspeed as both of the rearones, and you will notice the car "pop" as one of the wheels slip if you try turning on a non-slippery surface. In auto the magnetic clutch is only connected 5% of the time(it connects and disconnects several times a second) until the sensors find the rearwheels turn faster than the fronts, then the clutch connects more and more often, until it's connected almost all the time. when you regain traction it works its way down to 5% of the time again.
Hope you understood this, even thoug my english is a bit limited...

 

[JasonF]

Thanks for the explanation. That *almost* clears it up for me. I am still confused about the "clunking" you get when you flip into low, which I always believed was each of the front hubs locking. Is this true, or am I really just hearing the 'clutch' switching to full lock mode?
If it is the hubs each locking, how can they still pull in 4wd auto while in the 'unlocked' position?

 

[Jason_25]

The transition from low to high is achieved by the shift motor. It also cause the clunking noise.

The hubs are a sealed direct drive unit. They do not lock and unlock.