hello all, my '04 envoy front diff? hums/whines when I get above 15-20 mph in 4wd. no noise at all in 2wd. any and all thoughts? thanks, chuck.
'04 envoy "hums/whines" in 4wd
- Thread starter charlell8
- Start date
littleblazer
Member
- Jul 6, 2014
- 9,265
Is it really loud or just a slight hum/whine? Mine does this as well but it is not really any louder than the engine at speed. I don't know if it's normal though, for the very little I use 4wd I haven't really put too much thought into it though.
A lot of stuff rotates in 4HI that doesn't in 2HI. Some noise is normal. Has it changed since the last time you checked it out?
Also VERY VERY IMPORTANT is to change the transfer case fluid every 50K, which is not what most owners assume until they kill their transfer case from neglect and discover to their horror it's not a "sealed for life and ignore it" unit.
What's your transfer case maintenance history? How often have you changed or checked the level of the diffs?
Also VERY VERY IMPORTANT is to change the transfer case fluid every 50K, which is not what most owners assume until they kill their transfer case from neglect and discover to their horror it's not a "sealed for life and ignore it" unit.
What's your transfer case maintenance history? How often have you changed or checked the level of the diffs?
hey all, it's not really loud, but I can hear it clearly over normal running sounds. not at all like a tire rubbing against a mud flap. I don't recall it happening at all last winter when I used 4wd. my s.i.l. changed the fluid last spring, i'll have him check the level, but if I remember correctly, which is questionable, (age? to much weed in my younger days? some of both?), you cant really see what the level is. no dip stick. how would he know? thanks, chuck.
IllogicTC
Member
- Dec 30, 2013
- 3,452
May03LT uses a white zip tie. Stick it in just a bit, right below level with the fill hole. If you get a reading on the tie, your level is good, and the color of the tie allows you to examine the fluid itself for discoloration or other warning signs.
Some front diff. parts are constantly rotating, the big change in 4HI is now the pinion and carrier join the party the spiders and outputs have been having year-round. So, that may help narrow down specifically what's gone sour up there.
Some front diff. parts are constantly rotating, the big change in 4HI is now the pinion and carrier join the party the spiders and outputs have been having year-round. So, that may help narrow down specifically what's gone sour up there.
AWD V8
Member
- Jan 12, 2015
- 463
Are you using A4WD or 4x4?
You should not be using 4x4 on a hard surface face. If you are then the stress of the torque build up will cause whining of the drive train.
If you are using A4WD then front end parts are rotating that don't in 2wd, so you may hear some whining.
You should not be using 4x4 on a hard surface face. If you are then the stress of the torque build up will cause whining of the drive train.
If you are using A4WD then front end parts are rotating that don't in 2wd, so you may hear some whining.
Mounce
Member
It's advised to not use A4WD, ever, because it puts stress on the clutches and can burn them out.
IllogicTC
Member
- Dec 30, 2013
- 3,452
I'd say it has its uses, in a mixed dry/wet scenario. The road I take to work, it's very easy to find spots that are dry and then other spots that have sheets of ice on them, because the drainage plan for the particular highway was "eh, just let it run from one side of the road to the other on banked curves." The useful scenarios when considering clutch lifespan is pretty limited, though, unlike what the dealer promised about "just leaving it on full-time."Mounce said:
I only put it in "a4wd" or "4hi" when I need it,which is almost always on snow. i don't use it for just wet roads.
Hi Chuck,
I am having very similar symptoms with my 2006 Trailblazer LT/4.2L/4x4 (75k miles). The guys at the dealership could only hear the hum/whine with the car on the ground, not on the lift so they weren't sure where to start. Car runs fine in 2WD. No warning lights or codes pop up and fluids were okay. Just curious what you ended up doing with your Envoy. Thanks.
Phil
I am having very similar symptoms with my 2006 Trailblazer LT/4.2L/4x4 (75k miles). The guys at the dealership could only hear the hum/whine with the car on the ground, not on the lift so they weren't sure where to start. Car runs fine in 2WD. No warning lights or codes pop up and fluids were okay. Just curious what you ended up doing with your Envoy. Thanks.
Phil
djthumper
Administrator
When was the last time you changed the transfer case and differential fluids? The transfer case should be done every 50, 000 miles.
Hi DJthumper, thanks for the reply!
The TB is at 75k and I haven't changed the fluids for either the differential or the transfer case, so there is my first problem. I suppose the smart thing to do is change the fluids first and see if that helps. Guys at the dealership checked these fluids trying to diagnose the issue, and reported that fluid levels were normal and clean (I assume that meant no metal filings or other junk).
The TB is at 75k and I haven't changed the fluids for either the differential or the transfer case, so there is my first problem. I suppose the smart thing to do is change the fluids first and see if that helps. Guys at the dealership checked these fluids trying to diagnose the issue, and reported that fluid levels were normal and clean (I assume that meant no metal filings or other junk).
djthumper
Administrator
That would just mean there were no metal floating at the top. If there are filings most would be at the bottom. I would definitely change the transfer case.
That's the kind of advice I was looking for. From delving through related threads it seems like not having the TC fluid changed @50K and driving with A4WD (used to do this before I realized it is just a bad idea) can combine to ruin my transfer case. Thanks for the help DJ.
rcam81
Member
Last winter my 07 TB developed a major whine in the transfer case when in 4WD. I ended up replacing the transfer case. The clutch pack was going out. I had done a fluid change at 51K miles. It was replaced at 91K.