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4x4 noise


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#1 mx71

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Posted 24 December 2017 - 10:18 AM

So we finally got enough snow here in Idaho to kick in the 4wd. Is 4x4 supposed to be noisier than 2wd? I definitely hear the front driveshaft spinning, but the whole truck vibrates a lot more at speed and it's almost like I hear a mild grinding/vibrating noise like bearings are too tight, or gears are operating dry. Is this normal? I know 4x4s weren't as eloquent in the 80s, and driving a true 4x4 at speed should obviously make more noise, but it even makes more noise around town, with the bulk of the sound coming from below me. Do I have a problem, or is this perhaps the chain in the transfer case doing it's job? There's also a lot more resistance in 4x4. If I'm on a slight incline and put the clutch in, it doesn't roll backwards as easily as it does in 2wd.



#2 thisismatt

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Posted 24 December 2017 - 10:26 AM

Well, are your wheels/tires the same size, and differentials the same gearing? Have you checked gear oil level? Transfer case level?
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#3 mx71

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Posted 24 December 2017 - 10:29 AM

Wheels/tires are same size. I have no idea about the gearing, but the way this truck was taken care of, I don't see any reason why any of the previous owners would make that mistake. Double checking the transfer case fluid level, and I had already checked the differentials when I got it, and the tranny has had a drain and fill with GL4.



#4 MaxChlan

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Posted 24 December 2017 - 11:20 AM

I may be using an incorrect term here, but I find that there is more rolling resistance when I use 4x4 (like you mentioned). I haven't ran in 4x4 at speeds greater than 40 MPH in a while, so I can not comment on any excess noise. I was told that you shouldn't drive on pavement in 4x4 with older 4x4 vehicles, but I do not know what. Let's see what Mike has to say about this...



#5 datzenmike

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Posted 24 December 2017 - 11:26 AM

T-100s are known to make noise it they have been abused.

 

Otherwise.. I would take a look at the front R-180 differential for oil. If never changed... then change it. Inspect the drain plug as it has a magnet on it that collects ferrous metals. If it has a black past and fine specks of metal this would be normal. If chunks this is not. Clean the magnet so you can better evaluate it when next you change the oil. Use GL5 gear oil. One liter is enough. Fill till to the bottom of the fill hole.  There should be a vent with a rubber hose going up higher than the frame. This is to prevent water from entering the differential when it is submerged. The rear differential should also have this and the transfer case. Old oil should be dark amber and clear. Milky or cloudy is water. 

 

Inspect the front trans case to diff driveshaft U joints. They should absolutely not move in any direction but turning so pull sideways on them as hard as you can you won't hurt them.

 

Your '85 will have automatic locking hubs? Are they working?

 

Last, are the two front CV driveshafts. Are the rubber boots split? This will let dirt and water in destroying them.

 

I wouldn't advise using 4x4 where it's not needed and if you can drive 40 then it should be in 2wd. Four by four is best in poor traction conditions so that any differences in tire diameter will be lessened by tire slip.


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#6 thisismatt

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Posted 24 December 2017 - 11:57 AM

Yes, real 4x4 which you have has no center differential, so should only be used when some slip is available
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#7 MaxChlan

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Posted 24 December 2017 - 12:08 PM

Yes, real 4x4 which you have has no center differential, so should only be used when some slip is available

Thanks! Now I know!



#8 mx71

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Posted 24 December 2017 - 01:05 PM

Well, I have been driving on the freeway with it so I'll stop that.

 

I changed the front differential oil with GL5. It was too dirty for my taste. I also greased all the grease points.

 

Transfer case was dry. I wonder if that could have been the issue? :devil:. Hopefully I haven't caused too much damage driving it the last few hundred miles like that.



#9 wayno

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Posted 24 December 2017 - 01:28 PM

That truck should roll backwards on a hill when you push the clutch in.

It is easy enough to check the rear gearing to make sure it was not changed.

A dry transfer case is not good.


 

 


#10 datzenmike

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Posted 24 December 2017 - 01:43 PM

Well running the trans case while dry was covered under abuse I guess. :lol:


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#11 mx71

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Posted 24 December 2017 - 04:48 PM

No bueno. I think it may be leaking from the output shaft, but I did spill a lot when I filled it.



#12 datzenmike

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Posted 24 December 2017 - 05:23 PM

A leak would explain why it was dry. The seal is about $20, not cheap.


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