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First DIY Transfer Case Fluid Change (w/ Pics)

103K views 23 replies 20 participants last post by  Muddeprived 
#1 ·
Hello everyone,

I decided to tackle the next project on my 2000 rav4, which was change the transfer case fluid. I didnt even know I had one till I read Haynes Manual and I didnt even know where it was till I researched this forum. I know it hasnt been changed in over 70,000 miles so I def. wanted to do it. So here are things I used to change the fluid:
1. 10qt oil catch pan w/ screen
2. Rags and big piece of cardboard
3. 1 qt. of GL-5 Coastal SAE 75W-90 gear oil
4. 10 mm hex wrench
5. Lubricant spray just in case bolt was rusty
6. 10ft of clear tube 3/8 inch thick (You dont need 10ft, but it was a good deal. Id say you need about 2 1/2 to 3 feet.
7. THE ALMIGHTY HAYNES MANUAL (even though they were very vague about the transfer case). To be honest I didnt even use the manual for this, but I always keep it handy just in case.


To start, I checked the transfer case dip stick, which is located behind the passanger side tire. If you turn your wheel all the way to the left you can see it sticking out. The owners manual and haynes manual dont even mention a transfer case dipstick. The right amount of oil is in the case, but the oil itself is dirty. Here is a pic from behind the wheel, under the car and then the dipstick.




After finding the location of the dipstick and checking the fluid level and quality, its time to find the drain plug. Its basically between the transfluid pan and the motor oil pan. Its right near the exhaust pipe, so if u follow it under the car you'll see it.



Now, its time to drain the old fluid. A strong turn clockwise and the drain plug is turning. THe drain plug had some gunk on it, so I cleaned it before putting back. I wanted to check how much fluid was in there so I know about how much to add. The haynes manual says 0.7 quarts, but i wanted to make sure. So i took an empty motor oil quart and put the fluid in there. The motor oil quarts have the measurements on the back so you can see how much oil is in it. The old oil filled about 3/4 of the quart so Haynes manual was about right.




After draining and putting back plug, its time to add the fluid. Now Im pretty sure there is a check/fill plug somewhere, but after reading horror stories about how difficult it is to find or get to, i decided to add the fluid through the dipstick, just like the transfluid. The dipstick is kind of hard to get to because of the distance, so this is where the clear tubing comes into play. I didnt find a need to raise the car or remove the wheel. I try and avoid excess work if its truely unnecessary. I dont think i'll even raise my car, unless i need to rotate tires or check brakes. ANyway, I used a 2 1/2 foot piece of clear tube. The squeeze bottle fits perfectly into the tube. I put rags under the area just in case I overfilled it or the tube came out. I also put the cardbard under this area too. Since the gear oil doesnt have the measurements on the back like the motor oil, it is kind of difficult to figure out how much 3/4 or 0.7 of a quart is. So every once in a while, I would take tube out, let it settle and check with the dipstick. I would add fluid until it got to the right area.


I must say, Im new to all this fluid changing stuff and this was a pretty simple, easy and quick project. I hope you all enjoy!!
 
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#2 ·
Great article, thanks,

Stephen L,

thank you very much for the great DIY article on Transfer Case Oil change.

I bought my 99 RAV4 (used) about 18 months ago and already added 20K miles on it, it recently started to make a "Da, Da, Da" noise when I start accerlating from stop, it happens very occasionally, and I also hear occasional high pitch rotational noise - it seems to be from driver side front (listening while I am driving). I checked the transfer case oil, the level is ok, but it smells badly, also dark/brownish.

I bought the GL-5 gear oil last summer, thinking about changing it and Rear Diff. oil, but couldn't open the drain hole on my first try, so did not do it last year.

I suspect the noise could be related to those two, so went to a local repair shop to have them done, the technician said they couldn't do it, don't have the special tools, and I need to go to a transmission shop. I had your article a few days ago and decided to Do-it-Myself. I went to a nearby auto parts shop to get clear plastic tube to fill from the dipstick, but they did not have it.

I ended up using two free "straws" from McDonald, extend the two together with glue tape, and taped one end to the oil bottle, squeeze the oil in, relax and let the oil bottle to "breathe" some air in and get back to full shape, then squeeze again... let is settle and measure with dipstick, ... job done without problem.

I also used the same method and changed the Rear Differential oil.

Both plugs had black mud (fine metal debris from mechnical robbing) and oil being much darker than the new oil, it appears the oil could possibly be original on my 85K mileage RAV4, or at least a few years old.

The RAV4 drives ok for two short trips today, I did not hear the noise after Rear Diff change. It had a bit "metal robbing noise" from driver front side after the transfer case oil change on the first trip, but it could take a little time for the debris to dilute into the new oil. or whatever, ... I am keeping my fingers crossed, wish me good luck!

thanks,

masterhu
 
#16 ·
I bought my 99 RAV4 (used) about 18 months ago and already added 20K miles on it, it recently started to make a "Da, Da, Da" noise when I start accerlating from stop, it happens very occasionally, and I also hear occasional high pitch rotational noise - it seems to be from driver side front (listening while I am driving).
masterhu, About that sound, does it feels like the gears are slipping while having vibrations? Like the car's not getting the speed it deserves until it gets hold of something for a while then gets back to being normal after having a momentum?

I am having troubles on my auto trans as well. My rav's not smooth on acceleration from dead stop if I put my foot quickly down on the gas pedal, it goes like nuts.
 
#3 ·
Did mine recently. Except instead of using regular gear oil I used Mobile 1. 75w-90 gear oil. Changed the rear differential at the same time and used Valvoline DuraBlend 80w-90. Since the change I've consistently gotten about +2 mpg.

Had similar results with my previous vehicle, a Nissan Pathfinder.
 
#4 ·
Excellent post. I'll do mine and the rear diff too after I have done a brake job (new lines, drums, shoes, springs and cylinders).

I will be using Royal Purple Synthetic 75w-90 for both rear diff and the transfer case.
 
#10 ·
ZAZ said:
Does anyone know the capacity of the AWD trans-axle?

I have just drained mine doing an engine change and took out 6 litres.

Thats a pretty expensive refill 6 litres at $6.00 per litre.
According to Haynes, an 1999 automatic 4WD trans-axel is approx 3.5qts (3.3 liters)
and a 1999 manual 4WD trans-axel is 5.3qts (5.0 liters)
 
#19 ·
Hello everyone,

I decided to tackle the next project on my 2000 rav4, which was change the transfer case fluid. I didnt even know I had one till I read Haynes Manual and I didnt even know where it was till I researched this forum. I know it hasnt been changed in over 70,000 miles so I def. wanted to do it. ..............


I must say, Im new to all this fluid changing stuff and this was a pretty simple, easy and quick project. I hope you all enjoy!!

This IS .......................... AWESOME !!!!
I just need to figure out what is the best viscosity of oil I should use. .... and the confusion about turning the drain bolt clockwise to open it??
I will be using Synthetic.

Also the filler plug where fluid is put in, what are the horror stories with that?
I guess I need to find the 2 and a half feet clear pipe somewhere to fill in from the dipstick.

It has been 8 years since this post. I wonder if the OP even has his RAV4 and even exists on this board anymore. LOL.
 
#22 ·
I just need to figure out what is the best viscosity of oil I should use. .... and the confusion about turning the drain bolt clockwise to open it?? I will be using Synthetic.
I guess I need to find the 2 and a half feet clear pipe somewhere to fill in from the dipstick.

Your RAV4 is different, you have a manual transmission, so there is no dipstick. You have 2 drain plugs to remove (one for transmission, and one for t-case). And even if there is 2 fill plugs, it's easier use only the one for the transmission... because the trans and t-case ''communicate'' together. If you are not able to put in 5L, drive your RAV4 a short distance. There is an oil pump in the tranny that sends oil to the pinion in the t-case. After you just need to top the trans fluid (if needed). Use synthetic 75W90.
 
#20 ·
It's past time for me to do mine again (AWD, Automatic). I did the refill through the dipstick tube way back when, so I should have the requisite tube and funnel somewhere. I remember it took a long time to refill due to the low slope and thick gear oil.

Anyone know if the 4.1's auto's transfer case is just a "straight differential" (between the front and rear), or if there's a clutch-pack, etc. ("limited slip") in there?
 
#21 ·
This is a great post, and I just wanted to update it with some part numbers and pictures for the drain plug and gasket.

Drain Plug: 90341-18021, torque to 27 ft-lbs.
Gasket: 90430-A0003 (previously 90430-18008)





The drain plug has a small magnet on the inside. It is important NOT to substitute for this drain plug the other, longer magnet drain plug (for example, the one on the rear differential) because you will run into clearance issues inside the case. You can reach your finger into the case after draining it, and you will see what I mean -- there are components within about 1 and 2/3". Use only the short plug.

Below is a picture of the new and old gaskets. These are aluminum alloy gaskets, and are the same gaskets as used on the automatic transmission drain plug. It is always tempting to re-use gaskets. But the picture shows why that isn't always such a good idea:



The picture shows that the aluminum alloy is well past yield and plastically deformed, so for this material we know its into strain hardening (cold worked). The plastic (inelastic, permanent) deformation is normal for a used metallic gasket, because it is by deforming that they work to seal mating surfaces against fluid leak, limit clamping force, and restrict thread engagement when torqued properly. The problem in re-using such a gasket is that the strain-hardened material will not deform as easily as a non-strain-hardened (ie, new) material, so it will not seal fluid leaks as well and the clamping force implicit in the original torque spec will not be appropriate for the stronger material (for connections with gaskets, the crushing resistance of the gasket increases the torque required to drive the bolt once the gasket surfaces are compressed).

Maybe its not such a big deal for a transfer case plug, but its something to keep in mind when inspecting any gasket you wish to re-use. But even for a transfer case, re-using a gasket too many times is likely to lead to leaks, over-torquing, stripped threads, or all of the above.

The over-torquing is perhaps the most common/annoying of these problems for this particular bolt (and all the other hex-key bolts on Toyotas), because it has a hex key (Allen) head. If you encounter an over-torqued drain plug, you will likely not be able to break it free using the 10-mm hex head -- in this case, try a Torx T-55 instead, and plan to replace the plug. Also be sure to hit that plug with PB Blaster before you try to open it, and wipe the PB Blaster off the head socket before you insert the Torx socket. The Torx head will help you get the plug out, but it will likely deform the head. Below is a picture of a hex key drain plug which required a T-55 for removal, and you can see the damage. You might get one more use from a drain plug in this condition, but in my opinion, a plug like that is worth replacing to save the threat that next time it won't be so "easy".

 
#24 ·
I tried this tubing method this past weekend and had little success with it. It appears I can pump a couple ounces into it and then it starts pouring out. Feels like pressure build up forcing the fluid out. I cannot get the fluid level up to where it needs to be on the dipstick. Right now it's at a 1/4 inch up on the stick and no more fluid will go in. All the other fluids were simple to flush/fill. I tried to find the breather hose to see if maybe it was clogged but I cannot locate it.

Any suggestions?
 
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