Unexplained 4x4 binding

Wahugg

Original poster
Member
Dec 4, 2011
87
Hello all,

I am afraid something maybe amiss in my 4x4 drive-terrain. It works in every way but the part that is worrying me is the amount of binding I am experiencing when I do turns past 1/2 of the maximum turning radius.

Now this is not normal 4x4 hop or bind up. I have always driven 4x4 vehicles so I know what normal bind up should feel like, but I have never felt this on my truck before so that is the main part that is worrying me. Here is the technical data for diagnostics:

-Service 4x4 light OFF
-Switch Works YES
-Actuator motor sound YES
-TCCM motor sound YES
-Right wheel spins off the ground NO
-Front diff fluid CLEAR 9k on it
-T-Case fluid CLEAR 9k on it
-Binding not present in 2x4
-Binding became apparent once switching from 4x4 high (no binding), to 4x4 low (clunk heard but no binding and it worked as expected), then back to 4x4 high (binding very apparent)

Like I said the 4x4 works but the amount of binding is scary. It's almost acting like one of my tractors with a locking front diff. Might anyone have any insight in why this might be? And no this is not pavement, this is on my farm with very slippery dirt, gravel, or grass that should allow for ample slippage.


Thanks for any insight on what the noise or condition might be!

-Wallace
 
Last edited by a moderator:

RayVoy

Member
Nov 20, 2011
939
What year, no place yet to display?

If this occurs after you have gone from 4low to 4hi, the problem must be in the transfer case.

I don't think it's possible, but it sounds like the rear is in 4hi and the front stayed on 4low (or the opposite).

Maybe something broke, maybe a bad clutch, or two. :undecided:
 

Scooter Scott

Member
Dec 7, 2011
60
Can you jack up the whole truck, put it in gear, and monitor the rotation of the tires by putting some chalk lines on the tires and count how many revolutions it does within a set amount of time? That would atleast let you pinpoint which end to pay attention to...just a thought
 

Shdwdrgn

Member
Dec 4, 2011
563
You know, I get what I would think is excessive binding quite often when in 4x4. Usually I notice it most when turning on reverse, or after having backed up and turning while going forward. It seems like I turn the wheels about half way, and it feels like the engine just stalls out and I can't move forward until I straighten the wheels a bit. It doesn't always bind up like this, and when it does happen there is no hopping, and never any dash lights. I just changed all my axle fluids to full synthetic and replaced the TC fluid in September. I just assumed it was one of those quirks with this platform.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
In my experience, our vehicles weigh too much to hop the tires. The driveline will bind up and stall the engine at low throttle before it will skid a tire. Unless you're on ice, I think it's impossible to not get binding in 4HI and 4LO unless the splined disconnect has failed to engage, or your transfer case clutches are shot.

Excessive binding may be grabby transfer case clutches, caused by too low fluid, too old fluid, or (if your fluid is fresh and full) damaged clutches or a TCCM that's commanded the encoder motor to apply too much pressure to them. Clutches can become damaged over time by excessive use of the A4WD mode, which at a minimum applies 5% torque to the front tires, and which IMHO should be shunned if you're not in the very specific conditions where it's useful. (Partial snow/ice and partial wet pavement COMBINED with some insane need to push the envelope and use a lot of power.)

Many folks used to think that the open front differential would prevent driveline binding, but I did a drawing I'll post here for the first time (I expect everybody to bookmark this and use it to educate others). Even an OPEN diff moves in an arc that's different from the front diff to the rear diff, and that makes the AVERAGE RPM of the front tires and rear tires different when you're in a turn. The transfer case attempts to lock them together and there's the issue.

envoyturning.jpg
 

navigator

Member
Dec 3, 2011
504
this might be stating the obvious but this binding, is it happening on hard surfaces (pavement, hard dirt) or when offroad?
 

Shdwdrgn

Member
Dec 4, 2011
563
navigator said:
this might be stating the obvious but this binding, is it happening on hard surfaces (pavement, hard dirt) or when offroad?

I was going to say its always been on pavement, however I got to thinking... Many times when I've noticed this happening is when I'm backing out of my driveway. The only time I'm in 4WD to leave the house is when we've had a heavy snow. So in all honesty, I would have to say the road conditions don't seem to be a factor.
 

Wahugg

Original poster
Member
Dec 4, 2011
87
navigator said:
this might be stating the obvious but this binding, is it happening on hard surfaces (pavement, hard dirt) or when offroad?

Like I stated in my first post, it's on a farm with a gravel road, dirt fields, and some rye/grass/very loose dirt trails. I do not use any form of 4x4 on any kind of hard surface (asphalt or concrete).

the roadie said:
Excessive binding may be grabby transfer case clutches, caused by too low fluid, too old fluid, or (if your fluid is fresh and full) damaged clutches or a TCCM that's commanded the encoder motor to apply too much pressure to them. Clutches can become damaged over time by excessive use of the A4WD mode, which at a minimum applies 5% torque to the front tires, and which IMHO should be shunned if you're not in the very specific conditions where it's useful. (Partial snow/ice and partial wet pavement COMBINED with some insane need to push the envelope and use a lot of power.)
^ Thanks for your words of wisdom Roadie. The fluids are fresh and not low. I will do a change for good will but I think my case may end up being one of the later two you mentioned. Also I picked up from the OS months ago that A4WD is pretty much useless, so that rules that out as a cause. Do you happen to know how hard it would be to crack open the TC and replace the clutch pack if that ends up being the case?

the roadie said:
Many folks used to think that the open front differential would prevent driveline binding, but I did a drawing I'll post here for the first time (I expect everybody to bookmark this and use it to educate others). Even an OPEN diff moves in an arc that's different from the front diff to the rear diff, and that makes the AVERAGE RPM of the front tires and rear tires different when you're in a turn. The transfer case attempts to lock them together and there's the issue.

http://www.roadie.org/envoyturning.jpg
^ And yet another lesson learned today. Thank you!

Thanks all for the suggestions. I have not been able to check it out to much due to ACT testing, school, work, and a girlfriend. Seeing I have a dedicated 4x4 farm truck I am not in the biggest rush, but it still is nice to know I have 4x4 underneath my feat which I will need when winter is fully upon us, and on the farm. The only things I can confirm are that the fluids are clear for the front diff and the TC.

-Wahugg
 

Wahugg

Original poster
Member
Dec 4, 2011
87
Well all, I have some updates.

I got off work today and headed home to go and further experiment with my 4x4 system with various results.

In A4WD, 4x4 was confirmed to work, and absolutely no binding even on full turns

In 4wd High things were quite different. There was moaning on turns past 1/2 and on full turns there was a huge knocking sound. Just imagine a piece of re-bar bouncing between the prongs of a pickle fork. That is how severe it was, and also this was accompanied by the binding feel/moan. If I put it in neutral the knocking sound would subside but was still able to be felt in the steering column.

In 4wd Low the knocking was insane. This is where the story gets interesting. Before I could even execute a 1/2 turn there was a huge clank, and the truck lurched forward. I though I just broke my spline dis-connect or something. Well I got the wheels strait again and continued forward with out any noises. All was normal. So I tried to do a turn again and no binding and no bad noises. I even felt the wheels hop like I am use to.

All of he following leads me to conclude that one of my clutches were stuck to another if that is possible. I ruled out the front diff and spline dis-connect because in A4WD there were no ill effects, when both were utilized and engaged. The reason I would not have felt the bad clutch was due to the TC only putting out 5% power to the front. Not enough power to cause a notice. 4 high showed the effects greatly due to the clutch being fully engaged. 4 low must have caused the two stuck clutches to separate due to the extra torque it provided.

Does this sound like a valid conclusion? The 4x4 system works now after the clank, with no bind up or un-expected sounds, so I am pretty sure nothing is broken.

Any comments or opinions on this would be greatly appreciated.

-Wahugg
 

Mark20

Member
Dec 6, 2011
1,630
I've had this binding since day one. I've just attributed it to 4wd. Once a month I do run it in 4wd but only really need it a couple of times during the winter.
 

Wahugg

Original poster
Member
Dec 4, 2011
87
Well here we go again at this.

Since the last time I posted the binding has been non apparent and not a problem other than the the usual sound and slight feel of the wheels hopping on gravel. It is non noticeable on grass/fields.

Yesterday I was hauling up a 750 gallon tank of diesel out to one of our more remote equipment/storage areas. Combined weight of fuel, tank, and traierl would put me right around 6.5k. This is on a farm not above 15 miles an hour so weight is not a huge concern to me.

My rear end was sagging a bit, and my front end was pushed up due to the weight. (If this was a road way trip I would use a proper WD hitch, but this is acceptable on the farm). I was driving and I heard a small clicking coming from the front end. Just imagine when you were a kid and you put a card in your rear spokes to make a clicking noise. That is the exact same thing I was hearing coming from the front left side of the truck. I thought maybe it was a corn stalk stuck up under the frame hitting something and did not think anything more of it at the time. Heading on back I encountered some steeper hills, so I would throw the truck into 4low to utilize the extra torque of the lower gearing.

I noticed the clicking was gone and I thought that was quite strange once I had the 4x4 engaged. Even if were not on the hill the clicking had subsided. Once again I didn't think to much of it and thought it was a corn stalk that had now fallen off. Well I took it out of 4x4 when I was backing up onto the cement clab and guess what, the clicking was back. Once the trailer was unloaded the clicking was gone even in 2x4 mode.

Then it hit me

Could it be a bad CV joint? With the rear sagging and the front lifted up some, that would but the CV joint at a steeper angle and could show the signs of a bad joint more easily. When the 4x4 was engaged it put enough power to it to keep the clicking if that makes any sense.

This could explain excessive binding in a turn and the clicking noise, but not the lack of symptom for a month or so.

Does this sound like a valid idea?

I haven't had time to try and pull the shaft to see if that would cause the clicking to go away, but that sounds like a plan for tonight.

Anything else this might be? Hopefully not the front diff.

Thanks for any input!
-Wahugg
 

Bartonmd

Member
Nov 20, 2011
545
Yeah, smells like a bad CV joint, to me... Only makes noise/binds when it's under load, or maxed out on angle...

Mike
 

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