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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| Transfer Case and Differential "Noises" During Engagement
Hi all.
Anal compulsive me, I "exercise" my transfer case and differentials WEEKLY (on both G's). I've noticed 3 things lately.
1- Lately, the Transfer case in the G55 (39k miles) has been making a "rumbling" noise with slight vibration when switching the button from high to low, and before placing back into Drive. It lasts but one second. It is MORE pronounced at slower speeds (10-15mph) and LESS noticeable at the max engage speed of 25mph.
2- The REAR diff lock makes a mild to moderately audible, "bang" upon disengagement, especially while making a turn.
3- The Center differential can take up to 30 seconds to disengage, even with pronounced "zig-zagging" on grass and gravel roads in my "front yard."
I would just like to know some ideas before I take it into the dealer (a little preemptive knowledge goes a long way with our dealership here!!). It IS still under warranty!! How do most dealers even TEST the diffs in most cities??
Anyway, I am so very thankful for this site, a way you can freely ask and receive!!
Any input at all would be very appreciated.
Greets!
Edited by G-AMG 4/28/2007 11:18 PM
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: Transfer Case and Differential "Noises" During Engagement
Patrick,
I have no clue what the rumbling noise could be - my transfer case is quiet as the desert during all activities. You may have your
dealer check it.
You should not "excercise" the transfer case of your 280GE on pavement. The binding effect on hard surfaces could be harmful.
http://4x4abc.com/4WD101/driveline-bind.html
The binding of components is also your problem of the 463 transfer case disengaging late. The built up tension keeps it from
disengaging freely. Zig-zagging makes it worse! To disengage the transfer case needs absolutely equal rpm front and rear. Turns
create huge differences. http://4x4abc.com/4WD101/abc4.html
If you absolutely have to excercise your transfer case give it ample time to disengage (could be several minutes). Go dead
straight and be extra careful on the gas. Applying throttle during this process can bend internal parts (possibly reason for your
rumbling noise).
The "bang" sound of your rear diff disengaging means you are doing something very wrong. DO NOT make turns after disengaging!
Go dead straight (best even without touching the steering - the vehicle will then find the straightest line itself). DO NOT apply power!
The 45 degree shoulders of the diff lock teeth force the activation sleeve back (rather than finding its own path slowly). The forcing
back causes the bang and it will bend the activating finger of the diff lock.
All diff lock and transfer case actions should be inaudible.
We discussed this subject last week or so and I posted pictures of the internals there.
So, so far your excercises have stressed your vehicles more than helping them to stay healthy.
Edited by 4x4abc 4/29/2007 1:04 AM
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Transfer Case and Differential "Noises" During Engagement
Harold,
thanx for the experience and insight, although I am confused, with regards to previous posts/advice about disengaging the diffs.
From my recolection, I though if you disengage while driving straight, there will be no "differential" rotation between the two wheels, so the diff will have no reason to disengage??
And, of course, I an not doing this on a paved road. I'm driving around the "front 40".
In regards to the speed during diff disengagement: I was going off the "G-wagen Sales Video" where the demo driver seems to be cruising along at a "preatty good pace" while disengaging the diffs. |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: Transfer Case and Differential "Noises" During Engagement
The difflocks will not want to disengage under load. If there is power to the axles or there is load due to turning they will not want to disengage and if they start to there will likely be damage to the engaging "teeth". They need time to come out of engagement sometimes and straight line driving and coasting will get them to release. Deceleration can load them as well as acceleration, its that spot between that will let them disconnect. I don't think you have to be going dead slow, you just want to give them time to release before turning.
My operators manual says: Engage the difflocks when the vehicle is standing or traveling at a slow speed (walking speed). Do not engage locks when the drive wheels are spinning.
Change direction slightly several times if one of the indicator lights fails to go out after the locks have been disengaged.
I think the key is gentle steering wheel inputs to help unload the lock, I find they come out driving straight. I have full front/rear difflocks in the tractors I farm with and use the feature often. It is the same set of rules, Don't engage with a wheel spinning or under load, to release don't turn or try to release under power.
-Dai
Edited by dai 4/29/2007 12:15 PM
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Transfer Case and Differential "Noises" During Engagement
"Change direction slightly several times if one of the indicator lights fails to go out after the locks have been disengaged. "
That is exactly what I am doing when I say "Zig-Zag", I gently turn side to side, moving the truck around a foot or so each direction, but it will still take around 150 feet for the Red light to go out on the rear diff, after turning all 3 off.
In the "Old" G, the diffs disengage within 20-30 feet. I know the systems are apples vs. oranges. Could there be a vacuum line problem?
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AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| RE: Transfer Case and Differential "Noises" During Engagement
G-AMG - 4/29/2007 4:12 PM
...In the "Old" G, the diffs disengage within 20-30 feet. I know the systems are apples vs. oranges. Could there be a vacuum line problem?
Disengagement of the locks requires that the vacuum lines return to ambient pressure. It might be that by frequently using the lockers you have plugged the filter through which the air gets let in. These, are near the vacuum solenoids, which are near the brake booster & pedal position sensor. As I recall they look a bit like aquarium bubblers. Pull then off (maybe tape a cotton ball over the hose to prevent dust ingress), then try it again. |
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G-AMG
G-Class DIY Host
Date registered: May 2006
Location: South Texas
Vehicle(s): '04 G55, '80 280GE, '99 S420, '98 E320, 2011 E350
| RE: Transfer Case and Differential "Noises" During Engagement
Alan,
thanx for the idea. How long (distance and/or time) does it take for YOUR diffs to unlock?? How often do you recommend "exercising" things??
The only thing that would go against the plugged filter is: My engine compartment? You could eat off of it, and not enough dust to plug a filter.
Hmmmm, I should pull the line anyway and see what happens!!
Cheers |
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