Loud Clunking noise when awd or 4 wheel High

[gulfman]

I have been getting a loud clunking noise when going from 2 wheel high to awd or 4 wheel high while under way. I know the manual says there will be a noise, but how loud is to loud. Its sounds like the drive is about to blow. I asked the dealer to test it a long time ago, but he said little. The thing is a 2003 with only 42,000 miles. I hesitate to shift into awd or 4 wheel low without stopping first. Has anyone else had this experience? I know its 12 years old, but I rarely used it as I had a company car for all those years and only used it to tow my boat.

 

[Skauber]

Going between 2wd and awd while at speed is no problem. I don't think there's anything mechanical that will move when doing that, I think it's just an electrical clutch that is allowed to engage in order to power the front wheels if necessary. But when switching it to 4H or 4L you should always be stationary with transmission in neutral, as this will lock the transfer case. You should only use 4H and 4L on muddy or gravel roads, or on ice. Don't use it on pavement, as this will bind up and could cause serious damage to the drivetrain.

 

[gulfman]

The clunking occurs when driving along and going from 2 wheel drive to awd and/or 4 wheel high. I know to stop when shifting into 4 wheel low.

 

[Skauber]

You should also stop before going into 4H.

 

[Skauber]

This is from the owners manual:

Basic operating principles
• Do not use 4H (4x4 HIGH) or 4L (4x4 LOW) on dry, hard surfaced
roads. This may damage the drivelines and axles.
• Drive slower in strong crosswinds which can affect the normal steering
characteristics of your vehicle.
• Be extremely careful when driving on pavement made slippery by
loose sand, water, gravel, snow or ice.


Positions of the Control Trac system
The Control Trac system functions
in four modes:
• 2H (2WD HIGH) delivers power
to the rear wheels only. This is
appropriate for normal on-road
driving on dry pavement.
• A4WD (4X4 AUTO) provides
electronic control four-wheel
drive with power delivered to all
four wheels, as required, for
increased traction. This is appropriate for all on-road driving
conditions, such as dry road surfaces, wet pavement, snow or gravel.
• 4H (4X4 HIGH) provides mechanically locked four-wheel drive power
to front and rear wheels. The “4X4 HIGH” light will illuminate in the
instrument cluster when this position is selected. This position is not
recommended for use on dry pavement. This position is only intended
for severe winter or off-road conditions, such as deep snow, ice or
shallow sand.
• 4L (4X4 LOW) provides mechanically locked four-wheel drive when
extra power at reduced speeds is required. The “4X4 LOW” light will
illuminate in the instrument cluster when this position is selected.
This position is not recommended for use on dry pavement. Use this
position for off-road low-speed operation or when extra power is
required, such as climbing steep grades, going through deep sand or
pulling a boat out of the water.

 

[gulfman]

The 2003 manual says you can go from (2 wheel high to A4WD or 4 wheel high up to 55mph. ) ( Note: Some noise may be heard as the system shifts or engages.) What I'm asking is does anyone else get a loud noise while under way doing this. The noise is noticeably loud.

 

[Skauber]

Considering this:

• Do not use 4H (4x4 HIGH) or 4L (4x4 LOW) on dry, hard surfaced
roads. This may damage the drivelines and axles.

Just because the system will allow you to select 4H while at speed, doesn't mean that you should. If you select 4H, you lock the transfer case. If you do this at speed on the highway, you should expect to hear noises from the driveline. If you drive it like this, specially making a turn, then you risk severely damaging the axles and/or transfer case. If you hear a lot of clunking noises, then this may have already happened. Inspect the drive shafts and universal joints, these may have been worn and have excessive play in them. If not, you might have to get the transfer case inspected.

 

[gulfman]

Perhaps I'm not explaining myself very clear. Does anyone else get a loud noise when they shift into A4wd( if you have that option) or 4WD high while underway. The noise sound like a clunk and goes away. No noise after that. When at stop,( as the manual says to do) and shifting into 4WD low, the same noise occurs, at stop, and goes away. Sorry if I wasn't clear about the issue. Someone must have A4WD and have shifted into it under way as the road conditions got slippery from snow or ice.

 

[Skauber]

When going from 2H to A4WD there is no sound. I can't say for switching into 4H, as I don't do that at speed. I only select 4H or 4L if I am on slippery surfaces, and not while at speed or going down the highway as that could potentially damage my driveline and I'd like to keep it in good condition.

 

[thevalleyboy]

No noise on mine from 2wd to AWD, sometimes a clunk from AWD to 4H, but not normally, and a clunk when going from 4H to 4L - just did the transfer case fluid so hopefully a bit of the clunk goes away - I too typically only go into 4H at a stop, or going very slow. It's funny I typically only notice a slight clunk into 4H when in neutral and stopped, when going like 5km/h it seems to go silently. I understand the mechanical change from 4H to 4L so I understand that there is a physical change in gears - hence the clunk and for that matter the lock from AWD to 4H.

Seems wrong that you would have a clunk 2wd to AWD - might want to get that checked out