It is very important to know your Transfer Case is full! EVOs are especially sensitive to this and if it is not completely full you will burn up the expensive ring and pinion gears in the unit! If you fill the unit via the factory fill hole in the T-Case, it can fool you into thinking it’s full when it is in fact not. The small oil sump in the T-Case will make the fluid back up in the unit while you are filling it and come out of the fill hole to make it look like the unit is full! Do not believe this as it can cost you a T-Case!!
We recommend using Redline Shockproof Heavyweight (RED) in your Non-ACD EVO T-Case. For ACD T-Case owners, please use Diaqueen LSD ONLY. Note: We recommend changing the fluid every 5-10k miles, depending on driving habits and conditions.
If you do not follow these instructions perfectly and run the T-Case low or with any fluid not recommended above you can kiss your t-case good-bye! 99% of the time when a customer has a whining T-Case it is due to either low fluid or the wrong fluid!
The proper way to fill the transfer case when the unit is out of the car:
A) Set the T-Case up so the tail housing is pointing UP.
B) Fill the T-Case through the tail housing (where the drive shaft connects to it).
C) Pour in a full quart of fluid.
D) Install the unit in the car making sure not to spill the oil out of the tail end and that you have the small rubber O-Ring installed between the trans and T-Case.
E) Drive the car around the block.
F) Park the car and remove the FILL plug from the T-Case so excess fluid can drain to achieve the proper level in the unit.
G) Install fill plug and now you are 100% sure it is full and the ring and pinion will be happy.
Proper way to fill T-Case when unit is in the car:
A) Remove the DRAIN plug.
B) Take a hand pump and insert the hose into the drain hole. Tape, clean rag, whatever can be used to try to seal the area the best you can. Kevin M. found that a 3/8" pipe thread fitting you can find at any hardware store will fit and seal. Get one of those that will fit your pump hose with a barb fitting and you just found a great way to fill your T-Case safely without making a huge mess! Pic of it at the bottom of this page. Crude, but it works great!
C) Pump a full quart of fluid through the DRAIN plug!
D) Quickly remove the hose and install the drain plug.
E) Drive the car around the block.
F) Park the car and remove the FILL plug from the T-Case so excess fluid can drain to achieve the proper level in the unit.
G) Install fill plug and now you are 100% sure it is full and the ring and pinion will be happy.
Filling through the factory fill hole:
This is very dangerous and we DO NOT recommend it as it will fool you into thinking it’s full!
Fill the unit keeping track of the amount of fluid going into it. If it backs up and looks full, install the fill plug and wait 10 minutes. Pull the fill plug back out a repeat until you are sure you have almost one full quart of oil in the T-Case!
If your T-Case is whining STOP and get it rebuilt! If you do not rebuild it now and you wait for the gears to break you can then burn up the VCU or ACD LSDs and be out even more money! The center diff LSDs are very expensive and hard to find! The pic below is of a broken pinion due to a person that ignored the T-Case death whine noises:
Easy way to fill t-case from drain plug:
