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Discussion Starter #1 (Edited)
Changing Your Transfer Case Fluid

Tundra model featured in this write-up: 2008 DoubleCab, 5.7L, 4WD

Tools/Materials Used: Socket wrench with 12mm & 24mm sockets, torque wrench, pan to drain fluid into, paper towels, and some way to get new fluid into the transfer case fill plug opening (pump, squirt bottle, baster, whatever works for you), 1.2 quarts transfer case gear oil, and new gaskets for fill & drain plug (part# 90430-18008) .

If you have ever changed the oil in your vehicle then you can easily handle this. For those of you that don’t know, the transfer case only pertains to 4WD models. Before you begin take the Tundra for a drive long enough to heat up the fluids (cold fluid tends to drain slower and less completely) and park it on level ground. Let it cool down enough that you can touch the exhaust pipe without burning yourself as you will be working in close proximity to it.

How do you find the transfer case? Slide under your Tundra via the driver’s side, about ½ way between the front & rear tire. Look up & towards the front of the truck. The transfer case is mechanism that has your front & rear drive shafts coming into it and is protected by a skid plate that is bolted onto it with four bolts. See pic below:



Using your socket wrench & 12mm socket remove the four bolts holding the skid plate onto the bottom of your transfer case.

Locate the fill & drain plug on your transfer case (located on the rear of the transfer case) see pic below:



Using your socket wrench & 24mm socket remove the fill plug (be careful not to strip the bolt as it’s a tight/awkward spot). Beware that a small amount of fluid may come out the fill hole, so have your drain pan & paper towels ready. Clean the fill plug, change the plug’s gasket & set aside. Always loosen the fill bolt first. What if you loosened the drain bolt first and then couldn't loosen the fill bolt? You'd be empty and out of service.

Using your socket wrench & 24mm socket remove the drain plug (be ready with the drain pan as the fluid gushed out pretty forcefully). Clean the drain plug, change the plug’s gasket & set aside.

Let the fluid drain completely. Wipe the area really well where the drain plug goes before installing the drain plug. Tighten the drain plug to 25 foot pounds of torque.

Use your hand pump, squirt bottle, turkey baster, etc to refill the transfer case through the fill opening with approximately 1.2 quarts of gear oil (I use Amsoil Severe Gear 75W-90 [Product code SVG-QT]). The transfer case is full when the oil begins to spill out of the fill hole. Allow it to keep spilling out of the fill hole until it has pretty much stopped. Wipe the area really well where the fill plug goes before installing the fill plug. Tighten the fill plug to 25 foot pounds of torque.

Wipe everything down & reinstall the skid plate, tightening the four 12mm bolts to 25 foot pounds of torque.

Be good to our environment & safely dispose of your used transfer case fluid. Done!Inspect for leaks after your next drive.
 

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Discussion Starter #3
...What is the recommended change interval?
Good question, I just looked up on the Toyota Owners site and it only mentions "inspecting" the transfer case fluid level at various times throughout the first 120,000 miles. However, under "Driving while towing" it shows that it should be replaced every 30,000 miles (My many years experience with Amsoil products would lead me to believe this drain interval could be longer...I'll probably change it about every 50-60,000 miles depending on towing frequency). My Tundra has about 28,000 miles and the fluid looked to be in very good shape (unlike the gear oil drained from the differentials). Many others have reported the same condition of their drained fluid.
 

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Job well done also.:tu:
 

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Nicely done... points for you. :)
 

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In case anyone needs it, here are the drain/fill bolt gasket part numbers that I got from Sparks today:

2007 5.7 4X4 90430-18008

I was able to get my local dealer to match sparks reduced price of less than a dollar and a quarter.

Best of luck!

Dawg

P.S. - I will also be posting the part numbers of the front/rear diff drain/fill gaskets
 

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It's pretty obvious when you get there that you may want to remove another skid plate that somewhat covers the fill plug, I only had a 24mm socket so I just removed two add'l 12mm bolts and had easy access to it.

Cheers!

Dawg
 
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