A loose dirt road is probably best, but yeah, wet grass would probably work too. Just make sure your 4 wheel shows engaged before doing it.

 

you can always jack all 4 wheels up and see if the 4wd works

 

i really like the 40 series. it gives a nice deep rumble all throughout the rpm range until about 4500 rpm. the high flow cat i later added didnt really change a whole lot. just gave it that kind of popping sound when you let off the gas (dont really know how to explain it) ill link a video of what it sounds like with the stock cat.
sorry video is kinda short and thats the sound at about 2000 rpm
97 blazer 40 series muffler - YouTube

 

if you want to make sure its working i would put it in 4x4. then put it in reverse. and then stomp on it. make sure you are on grass or gravel. if it grabs then the front is spinning but if the back tires just spin then its not engaging. i had this problem a while ago. i went through a couple actuators and solenoid switches and such.

i would also put the truck in 4x4 and reach under, grab the front driveshaft and if it is locked then the transfer case is working it would just be your actuator. check the lines to make sure there are no kinks or cuts on the lines.

also if you are turning and you have the 4x4 on, it will be hard to turn while the wheel is cut all the way. almost like it is binding.

 

if you turn the tires on bare cement you will hear one of the front tires slipping. But the best option would be to get on something slippery and try the reversing idea

 

Me too! Driveline-twin powers activate!

Sorry, couldn't help it.

 

Whenever I want to check on my Jimmy, I can put it in 4x4, then grab the driveshaft between the t-case and front diff. If it spins freely, it's not engaged. It may have a little play in it, but there should be a big difference between when it's in 2wd and 4wd.

To see if the front axle is locked, you can put it in 4x4 and try to drive a little on dry pavement. The steering wheel should be significantly more-heavy and the tires will skip on tight turns.

 

im gonna go out and try the reverse test right now, i'll get back to you with the results, here's hoping it works

 

that sounds sweet, what offset did you get?

 

well i tried the reverse test and it spun in 2 and 4, so it looks like i get to tear into my 4wd system, thanks to everyone for all the help