Fix for 4wd noise-T-case or front differential

Wolverine350R · March 15, 2007

I have a 99 Sierra that does the same. It has the noise in 4 auto, hi and low, but not 2wd. If I switch it to 4 auto on the move and then switch back to 2wd, whatever makes the sound seems to stay engaged until I go into reverse .

I bought the truck used (~96k) and I don't think it made the noise when I first got it as I drove it around in 4auto quite a bit, but then changed to 2 hi to see if I got a mpg improvement and when I went back to try to use 4auto it made the noise (and feels the same as if its in 4 hi, so now I only use 4x4 modes if the roads are slick.

Does anyone know what triggers the 4x4 if it is in auto mode??? I was originally thinking some of it could be a bad sensor causing it to stay in 4 high.

buckshot · December 14, 2007

I have a 99 Sierra that does the same. It has the noise in 4 auto, hi and low, but not 2wd. If I switch it to 4 auto on the move and then switch back to 2wd, whatever makes the sound seems to stay engaged until I go into reverse .

I bought the truck used (~96k) and I don't think it made the noise when I first got it as I drove it around in 4auto quite a bit, but then changed to 2 hi to see if I got a mpg improvement and when I went back to try to use 4auto it made the noise (and feels the same as if its in 4 hi, so now I only use 4x4 modes if the roads are slick.

Does anyone know what triggers the 4x4 if it is in auto mode??? I was originally thinking some of it could be a bad sensor causing it to stay in 4 high.

I have the same problem with my 2000 2500 chevy. Exact to a T does anyone have any ideas. Please help

buckshot · December 19, 2007

Well I jacked mine up to look at it and noticed my wheel was all wobbily. Turned out my driver side wheel bearing was shot. That was my problem hope this helps you all out.

blueflavor · December 19, 2007

i have a 2000 1500 off road that i bought used with a warenty and i too it i for that reason and they replaced all the seals and bearing in the front end and switched over all my fluids to synthetic and it has pretty much eliminated it all together

Westlotorn · January 19, 2008

i have a 2000 1500 off road that i bought used with a warenty and i too it i for that reason and they replaced all the seals and bearing in the front end and switched over all my fluids to synthetic and it has pretty much eliminated it all together

I had a 2001 Denali, 3.42 gears full time 4wd 6.0L, sold with 89,000 miles, never a noise, always very smooth operation.

Bought a 2002 Tahoe, 4.10 gears Auto 4wd option with 4 hi and 4 lo. 82,000 miles. Very noisy in Auto or 4wd to the point where I take it back to 2wd even when the road is snowy to get rid of this noise.

Put on Jack stands and ran in 4wd while listening. Front Differential makes noise at front imput bearing. Growling sound.

Growl gets much louder when turning on road.

Is this a poor design we have to live with? This makes the full time 4wd look like a shining star.

Looking for a recomendation to eliminate this noise. I don't want to rebuild the front diff and not solve this issue.

chartersj · December 10, 2009

Are there any updates on this topic? i have a 02 z71 206,000kms with a similar noise. No noise is 2wd, in 4wd hi and low it makes a light growling, whirling kind of noise when i accelerate, or off the gas that increases or decreases with rpm, there is a happy medium where the noise will go away while driving. it sounds more like its coming from the front of the truck then the rear but its hard to tell while driving it... any thoughts??

zedbear · December 18, 2009

I have the noise in 2wd as well as AUTO and 4HIGH. Its just much louder in 4x4. In 2wd, it's off and on but pretty steady at 50+ mph. I removed the front driveshaft and drove it around. Sound disappeared totally......

Hieneken49 · December 18, 2009

wow, i hope made the right decision on my 09 sierra, i always had dodges....

TYPE GENDY · December 18, 2009

I have same sound very faintly in my 02 z71 in 4 auto. If it warms up from 10 degrees maybe ill pull the plate and check inner axles for any play. no noise at all in 2wd

jdewolfe · January 19, 2011

Any updates on this? My truck makes noise in auto and 4 hi but nothing in 2wd. Thanks!

Jeff

xwire · February 6, 2011

add another one, mine started doing this today, more so when increasing speed. sounds to me like the front diff but I hate to get into it if nothing is going to come from it

Grebbler · February 6, 2011

My noise is in 4 HI. It growls and rumbles a bit like a bad bearing. It doesn't matter if it's on dirt, snow, or Teflon like frozen slush.

It is pretty quiet in 2Hi.

In 4 Auto I can't really tell it's on except that I don't get stuck.

What cases would I want 4 HI over 4 Auto?

This is my first 4x4 after a long line of 2wd trucks. While good weight distribution, careful driving and good snow tires have kept me out of trouble for the most part - I really like having 4x4 in those cases when it's needed.

I know 4x4 don't help you stop any faster (common argument against 4x4), but it DOES get you out of the way of someone else that can't stop as they are bearing down on you. I would rather suffer some noise than be without.

cwendel4 · February 6, 2011

I just saw this thread. For all out there, it seems there may be an issue no one is thinking about.

On the newer IFS trucks, correct me if I am wrong, the front diff is always turning. No locking hubs. This would mean the gears are wearing in a coast pattern. The poor wear pattern may lead to noise once the front drive shaft is engaged. There may be a break in proceedure that needs to be followed, like after 500 miles of easy driving changing the rear diff oil because of breaking it in.

Second, the front shaft rotates without a load in this type of system as well. The u joints may wear funny and when load is applied the joint near the axle goes bad and makes noise without any play in it.

If the pinion bearing is making noise, then it is bad and enough said.

Noise when turning when the axle has power applied sounds like a bad set of CV joints. Remember, the IFS trucks do use a CV joint axle on the front end to allow for the IFS set up. These joints wear and will make noise if they go bad inside.

To me, sounds like internal wear of the diff and bearings with other factors added. Any one that is a tech out there have any info.......

When I get my new 2011, I may just keep it in 4HI for the first 500 miles to make sure I break in both diffs properly before I get to hammering the new 5.3 with 6spd.

glrizzz · March 9, 2015

Also have a rotational thumping in front after accidently in 4wd too long on pavement pulling another vehicle on a dolly. EVERYTHING started smoking-axle differentials, transfer case, etc. Changed all diff/transfer case fluids, no metal filings, and u-joints seem good.

The thumping starts when truck is cold & increases rotationally as speed of truck increases til about 20 mph, then dissappears. May not happen until the next morning again. Any ideas? I'm stumped!