2021 Equinox AWD

[Joeyeyes1975]

Ok guys, need help with this one. I have a humming/grinding while driving in FWD WHEN ITS 20 degrees or below. When it’s 30-35 degrees no noise at all. When I engage AWD noise goes away. Here is list of thinks I had checked,transfer case, drive shaft, and different, wheel bearings and brakes. Had new tires installed made noise before and after. Checked everything out myself also had it at trans shop and 2 other repair shops. Any thoughts are appreciated let’s get this solved. Thanks

 

[PoManNox]

Can you pinpoint if the noise is coming from the front or back, or a specific corner? As cold as this winter has been for pretty much everyone, this is going to be near impossible to troubleshoot if it only does it at temps below 20F. There's fewer moving parts in FWD mode, vs AWD, which is also weird..

A fairly common culprit on the 2018+ is a bad carrier bearing on the driveshaft between the T-case and rear carrier, but this driveshaft shouldn't be rotating when AWD mode is not selected.

 

[Joeyeyes1975]

Noise coming from mid to rear. Had checked out when temps were low. Noise was present but can’t figure it out. Center bearing and whole drive shaft including transfer case and differential all are fine. Doesn’t make noise when on my lift or lift at shops. Only when wheels are on ground. The mystery continues.

 

[Brennb]

I'm having a similar issue with my 18 awd. whine/grinding in fwd, goes away in awd. Only does it in temperatures below freezing. My thought is the transfer case shift control motor. If I drive far enough in awd, and it heats up the gear oil, or I guess just the transfer case, it will lock into fwd without the noise. Sometimes when I shift into AWD (when it's freezing), I'll get a clunk as the axle engages. It's been below freezing here for 2 months, with lots of snow. I'm using a lot of fuel, lol. A break coming this week with temps in the 30's, so I plan to get underneath and check the connectors, and change the fluid. The motor (and connectors) appear to be above the fill plug, So I hope there is enough access to check.

 

[Joeyeyes1975]

Ok did a little more digging this morning. It’s cold this morning drove noise is present with FWD switch on AWD goes away like normal. Put up on lift, while in fwd on lift no noise when I put AWD the rear passenger wheel is not spinning all other 3 are. Is that normal in this vehicle I would think all 4 would spin?

 

[RIT333]

I think yours is operating as designed. The wheels which have the least amount of traction get the power. That is my understanding. Ideally, with 4WD, then you can get all 4 wheels to have equal power, but then, when you take a corner, the tires tend to hop, if on dry pavement.

 

[PoManNox]

Ok did a little more digging this morning. It’s cold this morning drove noise is present with FWD switch on AWD goes away like normal. Put up on lift, while in fwd on lift no noise when I put AWD the rear passenger wheel is not spinning all other 3 are. Is that normal in this vehicle I would think all 4 would spin?

The front and rear diffs are open (not posi or limited slip). In reality, one front and one rear should spin when all 4 wheels have no resistance against them.

 

[Brennb]

Warm enough to get under the car yesterday. trying to reach shift control module connecters was fruitless, even with the shield slid as far as it would go. Will have to remove exhaust to get in there (although that doesn't look that difficult). I did change fluid, and it was clean. Very little material on the magnet. I didn't expect much considering I changed it 20000 miles ago. I'm just gonna limp along until sometime this year when I have better weather. Been working fine the last 3 or 4 days, as it has gotten above freezing. There are some Ohms checks for the module, but considering it only happens below freezing, I don't know if it would tell me much. Maybe stick it in the freezer, lol.

 

[PoManNox]

Warm enough to get under the car yesterday. trying to reach shift control module connecters was fruitless, even with the shield slid as far as it would go. Will have to remove exhaust to get in there (although that doesn't look that difficult). I did change fluid, and it was clean. Very little material on the magnet. I didn't expect much considering I changed it 20000 miles ago. I'm just gonna limp along until sometime this year when I have better weather. Been working fine the last 3 or 4 days, as it has gotten above freezing. There are some Ohms checks for the module, but considering it only happens below freezing, I don't know if it would tell me much. Maybe stick it in the freezer, lol.

I'd be curious to see how GM recommends accessing the T-case motor/module. Like you say, it's on top of the T-case with no access. Probably have to remove exhaust and the T-case itself. What is your thoughts on it being this motor/module? In my mind, it either works or it doesn't. It's a linear actuator that slides a collar back/fourth. Kind of an 'on, off' situation. I assume it has some type of feedback to the PCM, telling the PCM what position it's in and will set codes if it's not in the position being called for.

No presence of metal on the drain plug magnets is a good find. When I first changed these fluids on my 2021 @ 3yrs and ~32K miles, I don't recall the oil looking as bad as it does on most vehicles equipped with a PTU/T-case. As I recall, both the fill and drain plugs had magnets on them on my 2021.

 

[Brennb]

According to AllData, 2 bolts for cradle brace, 2 nuts for catalytic converter, 2 bolts for bracket brace, and 2 bolts/nuts to separate from tailpipe. Then you can remove the heat shield. The module and plugs will be accessible. As for why I think it's the module. I have had issues both ways in the past. Last year it didn't want to lock into awd when freezing. I changed the fluid, and of course the weather changed, and it didn't happen all summer. This winter it wouldn't fully disengage to fwd. I can hear the motor run when I push the switch both ways. But I don't know it is getting full voltage, or if it is just weak. There was a poster I believe posted here that asked if there should be fluid in the shift motor, he said he got a couple of LITERS of fluid when he removed his. The whole transfer case shouldn't have more than a half liter. He never returned to explain. My thought is mechanically the transfer case seems to be OK. I would like to examine the electric/mechanical aspect before I go further.

 

[Brennb]

Just to update this, and I don't want to hijack

Joeyeyes1975 thread. I'm convinced it's the shift control motor. I'm ordering one just to have when I get to removing the exhaust for access. When I said I could here the motor shift both ways it was above freezing. Now being below freezing I can only hear it shifting to FWD. Trying to shift to AWD I get a chain rattle/grind. It has worked both ways as far as engaging. I've been careful as far as driving to force (not really the right word, slow speed engagement) one way or the other. Today it got to 33, and it shifts fine, lol. I have schematics to test, but I'm almost positive the motor is the issue. It's hard to find info on this unless you supply very specific search terms. Anyways, I'll update in a week or so. If Joeyeyes1975 (the year I joined the Navy) is OK, I'll post here, otherwise I'll start a new thread.​