Rear Differential Fluid Change

[jp213a]

Procedure for changing the rear differential fluid in a 100:

Draining:

Drive the vehicle to warm-up the gear oil. Park on a level surface. It’s not necessary to raise the vehicle. Remove the fill plug first. It’s located on the back of the differential housing. It has a 24mm head (verify before starting work) but it is slightly undersized so a 15/16” socket fits better. Use a six point socket if available because the low profile plug head offers little surface area for the socket to grip and the head is soft. Be sure the socket stays squarely on the plug head as pressure is applied to the racket handle, especially if a cheater pipe is used. With the low profile head, the socket wants to roll off and round the corners in the process. Remove the fill plug before the drain plug so in case the fill plug is frozen or rounded-off and won’t come out you’re not faced with no gear oil in the housing and no way to refill. If the plug is frozen, spray it with PB Blaster brand penetrating oil and let it work for 15 minutes. Once the fill plug is removed, place a drain pan under the differential and remove the drain plug. It is located in the bottom of the housing, protected by a steel ring around the head. Use the same socket used on the fill plug.

Filling:

Remove the old sealing ring gaskets from the two plugs. Clean any metal particles off the magnet on the drain plug. There should only be a little finely ground metal dust (paste); no chips or chunks (i.e. broken gear teeth). Being able to see and evaluate the debris on the magnet first hand is one advantage of changing the fluid yourself. Clean both plugs with solvent and a wire brush so they look like new. If the corners are rounded, dress them lightly with a file. Install new sealing ring gaskets. These are hollow aluminum, crush type gaskets. Don’t reuse the old ones! Coat the plug threads with anti-seize. Clean the sealing surface around the drain plug hole with a rag. Install the drain plug and torque to 35 foot-pounds. Fill the housing with new gear oil. There is enough room between the back of the differential housing and the spare tire to insert the nozzle of a 1 quart lube bottle into the fill hole and hold the bottle close to level. Squeeze the bottle to fill the housing. Fill until lube barely runs out the fill hole. Clean the sealing surface around the fill plug hole with a rag. Install the fill plug and torque to 35 foot-pounds. Properly dispose of the old gear oil.

Materials:

2 drain plug gaskets, Toyota part no. 12157-10010 @ $.95 each from local dealer or $.69 from online discount dealer. Description: hollow aluminum crush type gasket with 18.2mm ID x 24.1mm OD x 2mm thick (prior to crushing).

3.5 quarts of SAE 80W-90 hypoid gear oil for limited slip differentials that meets or exceeds American Petroleum Institute (API) standard GL-5 (chose your own poison, e.g. petroleum based, synthetic, Redline, Amsoil, Castrol, Mobil, etc.).

Anti-seize compound

Tools:

Racket with 15/16” six-point socket is recommended. 15/16” twelve-point or 24mm six or twelve-point should work. 15/16” six-point PTI-drive socket (relieved corners) is the safest bet because it grips the six sides, not the six corners.

Torque wrench

>1-gallon drain pan

Wire brush

Rags or paper towels

Disposable latex gloves (recommended)

Notes:

1. Verify plugs are 24mm hex head; could be 10mm Allen head (requires Allen socket to use torque wrench) or other size
2. Drain plug gaskets fit 24mm hex head and 10mm Allen head plugs
3. A Torx T-55 bit fits a 10mm Allen
4. Fill and drain plug threads are M18 x 1.5mm pitch.
5. Drain plug has magnet, fill plug does not

[e9999]

anybody who's done this already can go over this how-to to verify all is correct and complete?
if so, will put in FAQ

[Cruiser4UGA]

Looks good to me, the only item I saw was the fill plug also has crush washers that do not have to be replaced, but for a dollar I think it is well worth it. The manual also calls for SAE 90 in warmer climates and 80-90 in cooler. Not a big deal I run 80-90 in Georgia. Everything is good from what I see.

[BeatenPath]

Great write up. If I can share two corrections from the Toyota Service Manual:

1. From the "Filling" section

Originally Posted by jp213a

Coat the plug threads with anti-seize.

The service manual for the 100 LC/470 does not specify to add lubricant or anti-seize to the treads of the fill and/or drain plug. I would not recommend this step as vibration could loosen the plug(s) with catastrophic results.

2. Also from the "Filling" section

Originally Posted by jp213a

Install the drain plug and torque to 35 foot-pounds.

Originally Posted by jp213a

Install the fill plug and torque to 35 foot-pounds.

The service manual specifies only 27 ft-lb of torque for both the fill and drain plugs in the rear differential. Again, this is a "dry" tread specification (no tread lubricants).

[jp213a]

The FSM doesn't specify anti-seize on the plug threads but it does have anti-corrosive, rust resistant, and adhesive propoerties. See following web site: http://www.valco-cp.com/Anti-Seize.htm A thread lubricant/sealer like Teflon paste is different than anti-seize. Basically, anti-seize allows the plugs to be removed at the next gear oil change with about the same torque it was installed with because there is no corrision.

The 2002 version of FSM specifies a fill & drain plug torque of 35 ft-lbs (acutual 36) for the rear differential. A torque of 27 ft-lbs is specified for the transfer case plugs.

[BeatenPath]

Double checked, and your right on for the torque spec's for the rear diff.

For the anti-seize on the fill and drain plug treads, it's really a mute point for this application. I tend to follow the FSM recommendations and have success in skipping this step.

[KathmanduCruiser]

I did the rear differential oil change today. Used Mobil1 synthetic (75W-90). Man, does gear oil stink or what......

I used a manual pump and a 10 foot tube to get the oil in. I had attempted to do this a few months back, but could not get the darn drain plug to open. I applied as much force as I could, but it just would not open. Today, I went and got a metal pipe about a foot and a half long and used that as a 'breaker bar'. It opened without any problems.

I followed the directions on the thread. Thank you, jp213a, for posting this and for everyone who added useful information. Easy job, probably took 45 minutes. Next time, it won't even take that long.

There was a layer of thick grease in the magnetic part of the drain plug and metal shavings, but nothing big - maybe a two or three milimeter layer.

[matt 105]

I thought this was going to be funny???!

[SWUtah]

Here is the other procedure. Drive to Lexus dealership at appointed time. Give keys to service rep. Go into lounge and enjoy the food and drinks, watch some TV or read the paper. About an hour later your LX has been serviced and it has just been also cleaned and you pay your $$ and drive off. I think that covers it

[9toys]

Are the rear differentials on LC's limited slip? My '04 Tundra's rear differential has a small metal tag hanging from one of the bolts that ID's it as a LSD, but my '99 LC does not.

[hoser]

Rear differential on your LC is not Limited Slip. US Market 98-99 LX's have limited slip but no available locker. If somebody really wanted one, I have one in the garage I can part with.

[jditom]

Great write up!
Do not forget about the front diff and the T case.
I did all 3 last night. Same procedure as above with a few exceptions.
For T-case you drop the skid plate (3 bolts) Use 1.3 Quarts of 75-90W.
Front diff, you have to drop the plastic middle skid plate (8 bolts).
The 2 bolts in the front diff are allen type. I have some that plug into my socket wrench. It also takes less than 2 quarts same grade as rear.

While you are at it greese that driveshaft espically the front part that is under the skid plate. Most shops are to lazy to take off the skid and greese the front DS Mine looked dry and never been greesed!
Took about 2.5 hours along with the engine oil change. Nice thing to do after the kids are in bed.

[Dandon]

Originally Posted by SWUtah

Here is the other procedure. Drive to Lexus dealership at appointed time. Give keys to service rep. Go into lounge and enjoy the food and drinks, watch some TV or read the paper. About an hour later your LX has been serviced and it has just been also cleaned and you pay your $$ and drive off. I think that covers it

Yes, but you end with less cash and less fun. Not to mention less of the diff oil stench that identifies you as a real ih8mudder

[KathmanduCruiser]

Did that one today. A few months ago, when I tried doing the TC and the diff oil changes, I was able to do only the TC. Since then, thanks to the wonderful new idea of breaker bars (I keep hearing that there is something revolutionary coming in the next few months called blinkers), I have been able to change both the diff oils.

The plastic skid plate is still leaning to the wall. There is some rust in the underbody that I want to take care of before putting that back in.

Originally Posted by jditom

Great write up!
Do not forget about the front diff and the T case.
I did all 3 last night. Same procedure as above with a few exceptions.
For T-case you drop the skid plate (3 bolts) Use 1.3 Quarts of 75-90W.
Front diff, you have to drop the plastic middle skid plate (8 bolts).
The 2 bolts in the front diff are allen type. I have some that plug into my socket wrench. It also takes less than 2 quarts same grade as rear.

While you are at it greese that driveshaft espically the front part that is under the skid plate. Most shops are to lazy to take off the skid and greese the front DS Mine looked dry and never been greesed!
Took about 2.5 hours along with the engine oil change. Nice thing to do after the kids are in bed.

[Jim_Chow]

I don't use any anti-seize on the bolts. There's plenty of gear oil residue on there to prevent it from fusing. I also just wipe off the magnet w/ a rag...wire brush is kind of overkill.

For the front diff, the 1 qt diff oil bottles won't work...not enough clearance. You need a pump.

I also use Mobil 1 Delvac 75w90 gear oil, 5 gal pail w/ lid pump.

[Jim_Chow]

Originally Posted by jp213a

The FSM doesn't specify anti-seize on the plug threads but it does have anti-corrosive, rust resistant, and adhesive propoerties. See following web site: http://www.valco-cp.com/Anti-Seize.htm A thread lubricant/sealer like Teflon paste is different than anti-seize. Basically, anti-seize allows the plugs to be removed at the next gear oil change with about the same torque it was installed with because there is no corrision.

The 2002 version of FSM specifies a fill & drain plug torque of 35 ft-lbs (acutual 36) for the rear differential. A torque of 27 ft-lbs is specified for the transfer case plugs.

Ditto for the '03 LX...36 ft-lbs for both drain & fill plugs for the front & rear diffs, 27 ft-lbs for the t-case drain & fill plugs. Front diff uses a 10mm hex bolt for the drain & fill, everything else is 24mm hex. Use 6 pt sockets only on the hex bolts.