Rear diff clutches

[Cavell]

Been told power to rear is sent when computer detects wheel slippage for AWD mode. I also heard there is a internal elec applied clutch pack for side to side power in diff. Ok I might believe that. But I saw the rear driveshaft turning while both rear wheels were on ground? So is there also a clutch pack for driveshaft input too?

[ssicarman]

Vue AWD rear diff is all mechanical.

From the service manual.

The rear drive module (RDM) in this vehicle consists of an aluminum housing which contains a gerotor fluid pump, clutch pack and a differential. It has a common fluid reservoir.

The on-demand rear differential distributes variable torque/power to the rear wheels via individual axle shafts.

The on-demand system operates as follows: only when front wheel slippage is encountered torque/power is proportioned to the rear wheels. As long as there is no front-to-rear speed difference; there is no torque/power to the rear wheels.

When front-to-rear wheel slippage does occur, the rear differential (gerotor) pumps fluid stored in the sump to a piston which actuates a clutch pack, which then distributes torque/power to the rear wheels.

The system has an integral protection device that reduces rear wheel torque when excessive heat is generated, thus protecting the rear wheel drive module (RDM).

[VUEmaniac]

Ssicarman is correct. It's 100% mechanical and quite fragile. If you haven't already, you'll want to change the fluid in that rear drive module at your earliest convenience to prolong its life. Saturn actually altered the point at which the rear drive would engage later in the VUE's life cycle as they were having higher failure rates of the RDM than they wanted. The effect of the change was that the RDM needed quite a bit more wheelspin to engage.

I was never really satisfied with the performance of the AWD system in the VUE, but I DID change the fluid every 30k-ish. miles and ultimately stopped using the versatrak fluid and switched to Royal Purple Synchromax. My ex-wife still has the VUE and I doubt it ever got changed again, but she's still driving it 10 years later and the RDM is still holding up at 140k miles last time I inquired. The RP fluid is substantially cheaper than Versatrak fluid.

Best,

[newbievueowner]

All mechanical and quite crappy really. I guess it's better than nothing in the snow but there are MUCH better AWD systems out there.

[Cavell]

guess i am wrong. i had a awd vue for 1 month and took out the driveshaft with a bad support bearing and never put it back in. now i picked up a 06 equinox and most of the info online seems to say the rear diffs are similar/same? i also have a failed support bearing on the nox so i did some digging this past weekend. i assumed the power to rear was minimal. i lifted front wheel and put nox in gear and the driveshaft to rear is turning slowly and the rear diff is making on/off noises. this is with both rear tires on ground. seems the nox has a switched clutch module in the rear and a clutch apply unit? so power is sent to rear ALL the time and it slips/applies when the computer tells it too? long story is: does the driveshaft with bad bearing always turn? on a nox?

[newbievueowner]

2006 Nox is the exact same AWD system as the Vue. 2016 would be different...

[newbievueowner]

I stand corrected, it looks like they still used the same (crappy) system in 2016 after looking at the microfiche!

Edit: Never mind.... just the same pic that they reused for 2016 (for rear axle shafts it looks like) ... the AWD diff assy is different.

[Cavell]

this transfer case for 06 nox is not switched than? it sends power to the rear when slip is detected and the rear has an electrically applied clutch that than transmits the power thru to the rear axles? so normally in dry conditions there is little to no power being sent to the rear? but the driveshaft does turn a bit? so why do people complain of driveshaft vibrations in dry situations like cruising on the hwy sometimes due to bad center support? it must be turning

[newbievueowner]

No switching, when there is wheel spin the drive shaft then spins faster and the gear set in the rear diff spins up and creates oil pressure to engage the real clutch packs an give AWD. Would actually be OK if it was more robust and was allowed to engage much sooner. Instead, because GM starting having too many failures they neutered the RDM unit....

The driveshaft is ALWAYS turning but the AWD system only engages when needed or called for (ie: front wheel spin). If you elevated the front up with a jack and tried to spin the front wheels at all (ie: drive) it would jump right off the jack.

[Cavell]

what is the RDM module that plugs into the clutch pack on the input of the rear diff? it is switched i believe. i read a few posts about low speed binding of the rear and the dealers were changing out the clutch pack on the front of the diff. i think i even saw an exploded view of the diff and there is a typical side clutch pack for the left/right wheels. so the diff has 2 clutch packs. input from the driveshaft and output to the rear wheels

[fdryer]

Transfer case drawings. As you can see, zero electronics. All gears. Power takeoff from xmission thru a right angle drive to the rear drive shaft.

[fdryer]

Rear drive module. As you can see, the front half of the RDM is the clutch assembly. Clutch cover and clutch drum. All mechanical and hydraulics. No electronics.

The rear half of the RDM is a conventional differential.

[fdryer]

RDM, rear differential drawings. As shown, when the rear drive clutch engages, the rear pinion gear shaft turns the differential gear assembly. The differential gears drives the two half shafts.

[Cavell]

what does the black box do? i think my 06 nox uses this box setup

[fdryer]

Posts 11, 12 and 13 are for your '04 AWD. I do not have info for Equinox awd.

[newbievueowner]

Since the NOX, Torrent and Vue are all built off the same platform the AWD systems, drakes, suspension, rear diff, etc are the same between the 2. The pic above is not a rear diff from an 06....