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
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
