THey can be sealed depending on the location and relativity to moving parts. They are best to be sealed from the inside which does require removing the internal parts and being thoroughly cleaned.
If it is an automatic, it will not have a dipstick. It is a sealed transfer case.
How to remove a transfer case in a 97 f-250
about $1000
A 1994 does not have a control module on the transfer case. But it does have a 4x4 Actuator on the front differential.
drop the pan and replace it
NO. If you keep finding yourself ADDING transmission fluid often and you have no leaks but the transfer case is over full then you need to remove the transfer case and replace the seal in the transfer case where it bolts to the rear of the transmission.
Replace the seals.
To replace the transfer case on a 2002 GMC Denali, start by safely lifting the vehicle and securing it on jack stands. Disconnect the battery and remove the driveshafts from the transfer case. Unbolt the transfer case from the transmission and any supporting brackets, then carefully remove it from the vehicle. Install the new transfer case by reversing the removal steps, ensuring all connections are secure and fluid levels are checked before testing.
the viscous is located inside the transfer case... you need to pull the transfer case out and split it open. While you are there you might as well throw a fresh chain and bearings into the transfer case as well.
replace the seal
where is it at
Need to specify which headlights you have... you either have the dual composite headlights, or you have the sealed beam headlight. In the case of the former, you rotate the harness 1/4 turn counterclockwise and it pulls out. You just replace the bulb. In the case of a sealed beam headlight, you have to replace the entire assembly.