Is anyone familiar with this transfer case? The problem is that the full-time four wheel drive never engages the front axle. Its awful to drive in the snow. The part time which locks the front and rear axles together works properly but only the rear spin in full time. If i raise the jeep on jack stands and put it in full time, the rear only spin. Its not until i chuck the rear wheels will the front start turning. That would seem to defeat the purpose. I figured that if the rear tires spin when up on jack stands the front should be engaging cause this would simulate the rear tires spinning if i was stuck in snow. Is there a viscus clutch inside that may have worn due to improper air pressure or something else? Is there maybe a bad switch? Please help.
Your center diff sounds like it is screwed.
242 locks center diff in part time, 50/50’ing the torque to the front and rear
Also : if you have open diffs, you technically can spin only 2 tires, but one in front and one in the rear.
Well I’m not an expert on New Process Gear units, but…
If the full time mode does use a viscous coupling, it’s rare for them to break. They are usually extremely reliable. They work by shearing a high viscosity fluid causing the fluid to expand and putting pressure on the coupling causing it to lock the front and rear shafts. By just putting the truck on jackstands and letting the wheels spin (I’m assuming for safety sake you are just doing this off idle) probably will not be enough to shear the fluid enough to lock up the coupler.
If it uses an open center differntial for full time mode you could see this same scenerio on the jackstands. You have a very low amount of drag on the system and thus power is going to go to wheels with least amount of resistance. Which is typically the rears. If your center diff is broken odds are it lost some parts, ie: broke some gears. You probably would have noticed this unless they are sitting safely at the bottom of the tcase.
Part time would work fine provided nothing is fucked inside. As part time physically locks the front and rear driveshafts together by way of gears.
if the viscous coupler went then it would be in 4wd all the time, atleast thats how the 249 works. heres a helpful link www.jeepforum.com sign up and go to the Grand Cherokee section.