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Discussion Starter · #1 ·
Hi All,
I've added more additive to my rear diff but still get a groan - particularly on slow left turns.
Is there anything like a wheel bearing or brake pads which could also cause the noise?
Thanks,
Paul.
 

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The beast from Brazil
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When you changed the diff fluid, was there anything special to see in the old fluid? Metal particles or alike? Did you look at the ring gear and pinion for damage or wear? There are bearings inside the diff and also wheel bearings in the outer side of the axles. Any one bearing could start making noises.
But after you had add the additive, did you make several tight figure 8 turns, to get the fluid/additive mix inside the vari-lock? How much of the additive did you put in finally?
If you have a groaning sound while driving straight, it usually is not a problem with the additive, because there will be no speed difference between the two rear wheels, so the vari-lock will not do anything.
 

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Discussion Starter · #3 ·
Hi Frank,
I just sucked a bit out and added nearly two ounces more fluid (didn't see anything untoward in fluid). I did do a few figure 8s but I'll do a few more lunchtime in a big open area round the corner.
It's a really weird noise and sounds like rubbing almost but you do feel a slight judder as well. Can the transfer case produce symptoms as I need to change the fluid in that too?
Regards,
Paul.
 

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Discussion Starter · #4 ·
Just a thought, I'll try and make a recording on my phone and upload it so you folks can have a listen.
 

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The beast from Brazil
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When you do the figure 8's, do them as tight as possible, so that the Vari-lock will be activated and fluid pumped around. Was the fluid level low, that you had to add two ounces, or was it 2 ounces of additive? No leaks? Is the noise there when driving straight?
T-case can produce noises as well, important is to not let the fluid level get low and ofcourse regular fluid changes will help in longevidity.
 

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I need to change fluids in my TC and diffs as well because I'm having the same issue. Lots of groaning and some shuddering when I'm taking tight turns in my parking garage. Just bought the Jeep from the original owner with 65k miles and figured it'd still have the factory fluid in it, but who knows.
 

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The beast from Brazil
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I need to change fluids in my TC and diffs as well because I'm having the same issue. Lots of groaning and some shuddering when I'm taking tight turns in my parking garage. Just bought the Jeep from the original owner with 65k miles and figured it'd still have the factory fluid in it, but who knows.
Is you jeep Quadra drive? If so, then don't forget to put the limited slip additive in the diffs. No additive or not enough of it, will cause skipping of a wheel in tight turns.
 

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Yup, '04 Overland. Maybe the stock fluid is worn out by now or a dumb dealership changed it with the wrong stuff since it was new, but it's definitely not quiet when turning. I test drove an '02 overland and made sure to try out the tight turns and it was completely quiet.
 

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Hi,
I just joined to Your forum as I saw here seems to be good tips... in some forums they're talking mostly beside the issue...

OK, back to the issue.
(Sorry my english as it will be a bit weird...)

I've got something similar going on with my WJ. It's CRD, but from tranny onwards, should equal to V8 models. Model '04 ('99-'04) and Quadra Drive.
T-Case oils were changeg 'bout a year ago.
Front/Rear last November.
For T-Case, original 247 oil, just checked oil is on a right level (nearly comes out when plug is taken away).
F/R, Mopar 75/140 + additive. Additive were added with a rule of a thumb.. 3/4 of a bottle to a front and the rest + 1 bottle to the rear (4 oz./Crown).

So... T-Case was driven on a "dry ground" (summer conditions, no sound) as it was changed a year ago, but F/R saw first time an asphalt/good friction as snow started to go away (I'm from Finland).
The reason I'm telling this is that while turning on ice/snow, I can hear that sound we're talking but it's not so easy. When we actually come to a point, I can't be sure when this problem/sound started. (Whether it started right after oil change, I mean)
Anyway, A couple of days ago, I turned left, slow speed, no snow, and then I realized this moaning sound as a first time. (Some guy from Aussi forum described it like a Chewbaca/Star wars sound...)
Then I tried it several times and there seems to be a relation to turning radius. If I'll turn "a little", it's like "Chewbaca"/whining sound. If I'll turn more it turns to a sound like wheel is rubbing to somewhere (it's not).

Just right now I'm in a middle of changing rear bearings/seals, because after changing the oil I got (realized?) a leak from right side.

So an other question is (as any axles has not been loosened yet) about spinning wheel(s) by hand.
(T-Case) Gear stick is in Neutral...
-I can spin the wheel but as according to a manual, if I'd like to check how locks will work I should spin an other tire to one direction an the opposite the the other direction, one round /sec. It's really hard to spin that speed... Why? Should it be so?
-And, even the Neutral is activated, rear wheel spins front and vice versa.
And, it's sticky too.

Got to go the garage to make a puller to get rear axle shaft out.
I believe, I have to open propeller shaft (right word??) to find out which end is really sticky.

So, could there be a relation? Between sticky wheels & sound?
Could the progressive clucth be partially close all the time? (If I try 4Lo there's still a huge difference, when turning, so front wheels can't be locked fully) but partially?
And, acceleration on a snow... I can feel, first rear slips a bit then front comes on and then we go...

Thanks Guys...
 

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The beast from Brazil
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The first issue still seems to be the vari- lock which is locking up when making tight turns. Did you make several tight figure 8 turns after changing the diff fluid, to be sure that the friction modifier is inside the vari- lock?
Regarding testing the vari- lock, you will need to have both front wheels of the ground. When you turn one front wheel, the opposite wheel should first turn the other way, but soon should turn in the same direction, as the vari- lock locks.
When you select the T case in N, you disconnect the transmission from the T case. You don' t disconnect the rear wheels from the front. So the progressive coupler in the T case will still lock the front wheels to the rear when you turn them with different speeds. Also its normal that the rear wheels slip a bit before the front engage, because there should first be a speed difference before the progressive coupler will engage.
The wheels are not that easy to turn, don' t know if that is what you call sticky?
You can remove the front propeller shaft, just 12 bolts in total when it has the CV joints.
 

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A couple of answers, after spending a day with rear axle, changing bearings... Got to make pullers, etc...

So,
-fluid change; those were changed before last christmas, no particular 8's were made, but there were no problems with it -> no need for 8's. I changed fluids because of km's. During the winter, we've had that much of a snow, I haven't realized this problem before - if it had even existed. The first turn on dry asphalt after winter revealed that sound. So, i can't tell whether this occurred right after fluid change.
-T-case in N position... I know it disconnects transmission, but I just wanted to test how sticky it is without it (spinning wheel by hand)
-all wheels off the ground, hanging by hand from propeller shaft, kicking wheels by foot... propeller steady, wheel "spins" by kicking it - locks seems to engage as after a few rounds I can't spin/move it (wheel) anymore.
All corners acts the same way, so I feel they're working? (locks)
-rear slipping... Yes, there's a short delay, before front end comes on, but I can feel it and that means it works - at least somehow.

-T-Case... one theory was that, progressive coupler is partially engaged all the time? But when I lifted the car, I'm able to rotate F/R properllers to an opposite directions. And, when turning, there's really a different feeling if 4Lo/TC is engaged. (Same speed front/rear)

Yesterday night, after bearings change, I drove for a short while to check that bearings are OK and if there's a difference after adding a bit more, 2 oz, additive.
After a few minutes of driving (11 PM), I was able to make that noise. It depends quite a lot of a speed. But - no whining?? Instead this louder noise, like tires were rubbing (as the others are describing it as well).
Coudn't repeat it with 4Lo. When I'm only moving 4Hi, like walking speed, all turned to a left (right) - not that much that steering will make a sound - this sound will appear easily. A bit more speed, and it hard to "find" it.
As I said - a short driving session at that time of the night.

I REALLY wonder if 2oz will change the situation? Only original oils/crown additive was used. All were filled up to a "hole" (Talking about last year).
How sensitive this mixture is? If car is leaning a bit forward (on a lifter), 4 oz is exact amount, but it's possible to fill a bit more of oil. Then there's "less" additive/oil liter.

Got a lot to do during eastern, but I'll try to go somewhere to drive "8"s - just to confirm it wasn't missing 2oz.... (on top of this 4oz + 1/4 bottle, which was added last year...)


...a bit more of this...
From the manual I have...
TRANSFER CASE
NV242 1.35L (2.85 pts.)
NV247 1.6L (3.4 pts.)
FRONT AXLE ± 0.3 L (1 oz.)
186 FBI (Model 30) 1.18 L (2.5 pts.)*
* With Vari-Lok add 0.07 L (2.5 oz.) of Friction Modifier.
REAR AXLE ± 0.3 L (1 oz.)
198 RBI (Model 35) 1.66 L (3.5 pts.)*
226 RBA (Model 44) 2.24 L (4.75 pts.)**
* With Trac-lok add 0.07 L (2.5 oz.) of Friction Modifier.
** With Trac-lok or Vari-Lok, add 0.07 L (2.5 oz.) of
Friction Modifier.

THIS manual, (looks like a factory manual for '02 Jeep GC WG) tells to add 2.5oz for both ends??? Usually "it's said" 4oz to rear??
So... could it be so that there's too much of it right now? Does anybody know what an extra amount will do/cause?
And... what is the right amount? (If it matters)
 

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The beast from Brazil
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My 04 manual also states to put 2.5 oz of friction modifier in each differential.
When you put in too much, it could affect negatively the lubrication properties of the fluid and cause premature wear to the moving parts.
 

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If we play with an idea, there's too much additive... what ever the amout is, but that much it will cause something...
What will it cause?

Now, when manual states 2.5oz and (as I heard, there's some plate attached to axles/each) the plate tells 2oz front/4oz rear, there's about 7oz (just added a bit to rear), which is about 3x the amount manual requires.

Does anybody have exact/confirmed info of what will happen when there's this much additive? (Talking about (more of a ) rear)

Frango100, does Your manual look the same? Those texts/values I copied are from '02 manual (couldn't find '04...)
If they're still the same, I wonder why do they have different amounts in a manual (has been wrong years) compared to those plates. (Got to see it by myself)
 

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The beast from Brazil
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In my 04 manual its written like this:

FRONT AXLE ± 0.3 L (1 oz.)
186 FBI (Model 30) 1.18 L (2.5 pts.)*
* With Vari-Lok add 0.07 L (2.5 oz.) of Friction
Modifier.
REAR AXLE ± 0.3 L (1 oz.)
198 RBI (Model 35) 1.66 L (3.5 pts.)*
226 RBA (Model 44) 2.24 L (4.75 pts.)**
* With Trac-lok add 0.07 L (2.5 oz.) of Friction
Modifier.
** With Trac-lok or Vari-Lok, add 0.07 L (2.5 oz.) of
Friction Modifier.
*** Includes 0.9L (1.0 qts.) for coolant reservoir.
****Nominal refill capacities are shown. A variation
may be observed from vehicle to vehicle due to

manufacturing tolerance and refill procedure.

I found in an other forum this:

I was told by a former Dana drivetrain engineer that too much LSD additive effects the viscosity and decreases oxidative resistance of the oil, that is resistance to oxidation from heat. Too little, of course, causes chattering which in turn wears the unit out prematurely or breaks it outright. He suggested that the best procedure is to use as little as it takes to eliminate chatter and no more, but you have to experiment to find that point. Each oil has slightly different friction characteristics so each may need more or less additive.

That process involves extra effort, which is why not too many people do it. It's outlined in some manuals, though it's more common to see, "Add X-oz." The one time I did it the hard way, it took me the better part of an hour. Starting with a newly installed plate-clutch type LS. I filled the axle to about 90 percent and located a parking lot near my home. With no additive I went to the parking lot and did some tight figure 8's in both directions, with a little power on. Chattered like a big dog. I added about half a bottle of the Ford additive and did some more figure 8's. At first it chattered just as bad, but you have to work the stuff into the unit and mix it well with the oil. After a little while, the chattering lessened considerably. I added about a quarter of a bottle more and that eliminated the chattering. For then. Later, it started to chatter a little so I added the rest of the bottle and it chattered no more. The instructions with the unit said to use two bottles, but I don't recollect their capacity in ounces, so I used half that.


 

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In other words, nothing should happen, if oils are changed as scheduled.

Jeep manual... a bit weird they recommend 2.5oz for both ends, as volume difference is about 2x.

Then, more driving... an aspahlt with quite a much of a sand (used during winter). A good place to test how wheels will act.
What I realized
-4Lo, tight turn, there's so much rattling (noise) because of the sand (front&rear turning the same speed) I'm not sure if the original problem (chattering?) exists then. But - still turning, stop the car, switch to 4Hi and continue turning, middle clutch/loch won't get loosen, until I reverse a bit.

Anyway, after that experiment, I can really "feel" that feeling when middle clutch is engaged, when driving 4Hi.

When driving on a yard, I told, wheels can "slip" pretty easy. When turning to a left, rear/left wheel "intermittently" stops/brakes.

Two choices, either rear axle engages or middle clutch. Actually 3... if both do it...

So next question,
-If middle clutch is open when car is standing still, what might make it to engage with low speed/ with that speed difference. In a way, it "works too good/fast".
-And actually the same question to rear axle.

I've heard, middle clutch might "burn"/get stucked. Does it mean it's engaged all the time? Or is it just like this is - works, but too quicly?

About the oils,
I've heard Mobil 424 should equal to NV247 oil. Or is it actually "original" 247 oil? As Chrysler does not make oils, they buy it from somewhere anyway.
Could be a bit cheaper to buy Mobil than Mopar...
 

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The beast from Brazil
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The progressive coupling in the T-case is in fact a clutch pack which uses pressure from an oil pump, which is driven by the speed difference between the front and rear propeller shafts. You have to see it like this; the pump housing is driven by one shaft and the pump output shaft by the other axle. Both axles the same speed = no pressure from the pump = no clutch engagement. When a speed difference exists between the two shafts, the pump will deliver pressure and the clutch will engage. Different tire sizes front/rear (or partly worn tires at one side and new on the other) will already cause the pump to work constantly and cause the clutch to wear rapidly.
When you use 4Lo, it mechanically connects front to rear and progressive coupler is not used anymore. Don´t know the exact buildup of the T-case to know what could be causing it to stay connected.
When the clutch pack is burned, it normally doesn´t engage anymore. It could be that for whatever reason the clutch is stuck in the engaged position.
The mopar fluid is indeed Mobil 424. I´m using it since the beginning.
 

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Thanks, for confirming it, as how I supposed it to work.

What might be the conclusion of this?
-T-Case "burned", stays engaged? It's not. It clearly let wheels to rotate for a while for different speed.
-T-Case doesn't engage at all? -> no sound? And testing on ice, front wheels starts to rotate. -> T-Case will engage.
-Rear?? "Kick" test will engage rear lock after a couple of spins. And during accelerating as well. And in the beginning of "test turn" to a left, wheels have clearly different speeds (vari-lok not engaged), but after a while inner wheel starts to brake. -> rear is still a possibility.

Sooouu....
No good reason why either one (or any) should engage when driving low speed and turning.
Some other peoples have got similar malfunction (can't be sure) and in those cases, clutch in T-Case has been an issue.
->front propeller shaft away, if there's no sound, I can be quite sure it's T-Case.

But, even faulty parts are there, why does it engage with that speed?
Got to change fluid first and see what happens.
Because, there's 120k km only on that car, I don't want to believe, Clutch in T-Case needs to be replaced.
Jeep can't be that bad, can it?
 

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Today... some shopping (not related to a car...) but, had to do some turns in a parking garage.
Now I'm 98% sure, this sound comes from the rear.
Can't feel anything on a steering, but the other wheel starts to brake (rear, inner). And sound itself is "quite far".

Does anybody have any ideas of, why hydraulic pressure will/would increase that much, vari-lok would start to engage?

And, sorry, no tests without front propeller... no time, yet.
Tomorrow I'm gonna leave to Taiwan for a couple of weeks, so we'll continue then with the shaft.
 

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Just A thought...

From a manual, section 3, "Vari-lok"
"(10) The left wheel should spin freely at first and
then increase in resistance within 5 revolutions until
the wheels cannot be continuously rotated in opposite
directions."

I can't spin it so many turns?? Vari-lok engages, let's say, after about half of those turns. That might be the answer, but why it does so?
(Front feels appr. the same, but no way for 5 turns)
 

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The beast from Brazil
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So it means the vari lok operates perfectly. It should engage WITHIN 5 revolutions, it doesn' t state that there should be a minimum amount of revolutions before it engages.
Still strange though that it still seems to engage when making tight turns, with the amount of additive you already have added. You are sure that the additive is the right one?
When you see my answer from the 31st, i had put a story from an other guy. There they state that you have to use as less of the additive as possible, because it will adversly affect the viscosity of the fluid( so the lubrication) and also the oxidation of the fluid at high temperatures. But you need to put in enough to get rid of the clutch chatter.
 
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