4wd Question

[FastLane]

I changed the front U joints on my 2010 Silverado today. They were getting pretty old. I have a question regarding the 4wd operation.

When the truck is in 2wd, does the front drive shaft from the transfer case to front diff turn or only when 4 hi or low is selected???

 

[Chris142]

Depends on if it has solid axles to the wheels or not. A truck that new won't have hubs so unless there is some sort of disconnect in the axles the driveshaft will spin anytime the front wheels are turning.

 

[Rand]

The front axle has an actuator..

 

[dumkid]

It depends. Some solid axle trucks have locking hubs, so you can disconnect the front driveshaft from the wheels. Some solid axle trucks there is no disconnect between the driveshaft and the front wheels. Some trucks (ifs and solid axle) have a center axle disconnect that will unlock one of the axle shafts and so the spider gears will spin but not the driveshaft. 2002 GMC 2500 suburban had ifs and a center axle disconnect

 

[Timmastertech]

Front driveshaft only spins in 4WD. Order of operation for transfer case engagement is the TCCM engages the front axle disconnect in the front differential then once the front axle is engaged it shifts the transfer case .

 

[FastLane]

Front driveshaft only spins in 4WD. Order of operation for transfer case engagement is the TCCM engages the front axle disconnect in the front differential then once the front axle is engaged it shifts the transfer case .

I always thought it spun but I could spin the drive shaft with my hand. This got me thinking I’ve been wrong all the time.

So once the transfer case is engaged it sends a signal to the front differential to lock.

Thank you.

 

[FastLane]

The front axle has an actuator..

I remember now. I had to disconnect the wiring harness when I dropped the front diff. I had an oil pan gasket leak a couple of years ago.

For whatever reason I always thought the front drive shaft was always spinning.

Thank you

 

[Rand]

I remember now. I had to disconnect the wiring harness when I dropped the front diff. I had an oil pan gasket leak a couple of years ago.

For whatever reason I always thought the front drive shaft was always spinning.

Thank you

IF it works like I think it does.. the actuator disconnects one side axle shaft.. which means the diff and shafts turn.. but not the front driveshaft.. The ram's use a similar system iirc.

 

[repairman54]

Front driveshaft does turn in 2wd. Actuator disengages R side shaft, but the driveshaft will turn some due to left side turning the differential gears, spider gears moving, oil in diff resistance, etc. Doesn't turn at full speed but it's not motionless either.

 

[Snagglefoot]

If it’s a 1/2 ton 1500 with an automatic shifted transfer case, the 2010 Silverado has a Magna Power Train MP3023. The code on the inside of the glovebox door will have NQH on it.

If it’s a manually shifted transfer case it’s a MP1222. From there a person can do more research. The simplest way is to tie a tight string around the front drive shaft, and two axles and drive it in two wheel drive. Anything rotating will wind the string around it.