Here are some pictures. Some other folks were asking about changing these fluids recently. Mine is a 2005 model. The transfer case is just a set of hypoid gears, and takes some form of 80 or 90 weight oil. Many use 75W-90 or 80W-90. The rear differential takes VTM-4 fluid, about 3 quarts (sold only as a gallon). I bought one quart of Mobil 1 75W-90 LS fluid and 1 gallon of VTM-4 fluid.
Both are incredibly easy to change. Crack the fill plug loose first (to make sure you can fill it back up), then open the drain plug. The transfer case takes about 2/3 of a quart of the gear oil. I used my small fluid transfer pump to do (related picture below).
The rear differential was also very easy, but my fluid transfer pump didn't screw onto the larger opening of the gallon jug. So what I did is empty the smaller gear oil bottle, "triple-rinse" it (and the pump) with a bit of the VTM-4 fluid into the drain pan, then fill the gear oil bottle with VTM-4 fluid to go into the differential. It took about 3.1 volumes of the gear oil bottle to fill the rear differential unit. The drain plug on the differential unit has a large magnet on it, similar to the transmission drain plug, because the rear unit has clutches in it similar to the transmission clutches. Related picture below.
I don't think Honda has a drain interval for the transfer case fluid. It's a very low-impact unit, under very little pressure. The fluid in that is probably good "for life", but I wanted to changed it anyway. It's really good for life now. The VTM-4 fluid has a drain interval of either 15k or 30k miles as I recall. I will probably do it every 30k. The car has 79k miles on it now.
Both are incredibly easy to change. Crack the fill plug loose first (to make sure you can fill it back up), then open the drain plug. The transfer case takes about 2/3 of a quart of the gear oil. I used my small fluid transfer pump to do (related picture below).
The rear differential was also very easy, but my fluid transfer pump didn't screw onto the larger opening of the gallon jug. So what I did is empty the smaller gear oil bottle, "triple-rinse" it (and the pump) with a bit of the VTM-4 fluid into the drain pan, then fill the gear oil bottle with VTM-4 fluid to go into the differential. It took about 3.1 volumes of the gear oil bottle to fill the rear differential unit. The drain plug on the differential unit has a large magnet on it, similar to the transmission drain plug, because the rear unit has clutches in it similar to the transmission clutches. Related picture below.
I don't think Honda has a drain interval for the transfer case fluid. It's a very low-impact unit, under very little pressure. The fluid in that is probably good "for life", but I wanted to changed it anyway. It's really good for life now. The VTM-4 fluid has a drain interval of either 15k or 30k miles as I recall. I will probably do it every 30k. The car has 79k miles on it now.
