I have a 2000s10 blazer 4x4 with push button transfercase. 4x4auto. 2hi. 4hi,4lo. I was tracking down a vibration and found fround that the front drive shaft is engaged all the time. The front axle is disconnectiong but tcase is not. Is there a common problem that I can look for? motor on tcase? a way to check for voltage to engage tcase motor? Any direction in this would be appreciated. Thanks Rick

 

Check out the Tech Article (DIY) Index link in my signature and look in the Transmission, Transfer Case, & Drivetrain section. See if any of those threads help out. If not, let us know what you have tried and the outcome.

 

Thanks for the info. I have done more checking. It appears that there is some kind of mechanical problem in tcase. In 2 hi I can turn front driveshaft by rotating a front wheel jacked off the ground. It takes considerable effort though. On test drive on road everything works as it should. It is just that the front shaft turns all the time. Is that normally so tight? Anything to worry about? Maybe just take front shaft off and replace or repair to take out all play? What is in tcase? A clutch pack?
Thanks Rick

 

If you can turn the front driveshaft with one wheel off the ground when in 2HI, your front axle is not disengaging.

There is a viscous clutch in the NV236 (Auto4wd) transfer case and it will take some, but not an excessive amount of effort to turn the front driveshaft even when in 2HI due to the clutch. But when in 2HI, the front axle should be disconnected so you should not be able to turn the wheel and have it turn the front driveshaft.

Just an FYI, the NV236 transfer case requires GM Autotrak 2 transfer case fluid. DO NOT substitute anything else regardless of who tells you otherwise.

 

Sorry! your right.I was in auto when I was able to turn the driveshaft. I guess my question is. How tight should the driveshaft be while in 2h. I can't turn driveshaft by hand when in 2h. I have checked and axle is disconnected. Raised wheel and checked. Everything works when driven. I was chasing a vibration, when I came across this. Drive shaft is turning while in 2hi. Nothing I have tells me if this is normal. It seems to be tight at trans case I haven't tried a pipe wrench or anything. I'm used to my old jeeps, with a lever on the tcase. When they are out of gear nothing turns. I really appreciate your trying to help. Rick Thanks for the tip on fluid. I haven't added, but can't say someone didn't before I got it. The cheap repair manual I have says dextron. Thanks again.

 

There should be resistance. How much... Not really sure I can put words to it. But I can say with 100% certainty that the front driveshaft will always spin. That is a quirk of the preloaded viscous clutch inside the transfer case.

 

Thankyou very much for the help. Rick