Learn how to change Volvo Angle / Bevel Gear and Rear Differential Gear Oil with our simple to follow step-by-step guide.

Volvo-angle-gear-and-rear-differential-oil-31259380-75w-90

Old Angle/Bevel Gear Oil – @60,452 Miles (97,289 Kilometres)
Old Rear Differential Oil – @60,452 Miles (97,289 Kilometres)
New Volvo Gear Oil – API GL-5 – 75W-90 Part# 31259380

Overview

This service is for the person who values long term performance and plans on keeping their car for a very long time or forever and will put a lot of milage on it. Example over 240K+ Kilometres. This post is to be used as a reference of how and when this service should be done as every persons driving style and conditions are different. It’s your decision if you want to change the gear oil or not.

Volvo does not give us an oil change interval for the Angle Gear and Rear Differential so many don’t change this oil over their ownership of their Volvo.

No Oil lasts a lifetime… Angle Gear and Differential Fluid servicing is far less expensive than having a component fail or get damaged due to failed fluid.

I recommend that the Volvo Gear oil should be changed at the following milage / kilometre interval below depending on driving conditions.

Normal Service: 100,000 miles (161,000KM)

Severe Service: 50,000 miles (80,500KM)

I will personally service my Angle Gear and Rear Differential Oil Every: 100,000KM

PLEASE NOTE: These drain intervals listed are NOT official numbers as there is no drain interval from Volvo. Therefore tune to your own use and driving habits.

Angle Gear/ “Bevel Gear” Guide

ONLY use the OEM API GL-5 75W-90 Volvo Gear Oil Part# 31259380. Redline and Liqui Moly both make a gear oil that meets Volvo specifications but may not have the same longevity and performance characteristics as the Volvo OEM gear oil. Unfortunately AMSOIL Severe Gear Oil is not formulated for the specification Volvo requires. Volvo OEM gear oil uses an olefin sulfide base oil which means it’s synthetic!

Tools and materials required: Level surface, safe access under vehicle, creeper, 13MM wrench/socket, oil extractor with tiny end tube, gear oil fill pump, 2 new copper plug gaskets, flash light, OPTIONAL Torque Wrench.

Set up vehicle on a safe level surface either on ramps or on a vehicle lift – the car itself needs to be level to set the oil level correctly so if you use ramps make sure the front and rear end are both on ramps
Go underneath and remove the front skid plate
Locate the fill plug on the Angle Gear
Throughly clean all surrounding areas on and around the fill plug – we want to be super clean so no foreign contaminates get into the angle gear as any dirt particles will cause damage
With a 13MM socket or wrench undo the fill plug and remove the copper plug washer with a little screwdriver or pick
Thoroughly clean the fill plug magnet of all captured fine metal shavings
Clean around the fill hole
Insert oil extraction tube – feed it into the angle gear slowly until you feel it reach the bottom of the gear housing
Depending on the extractor you choose once the tube is bottomed out you may have to pump the extractor or my personal preference is a air powered extractor so as its extracting you can focus on moving the tube around inside the housing closer to the end of extraction to effortlessly suck up the most fluid as possible – or you can get a helper to pump the extractor for you while you are underneath the vehicle
When you finish extracting I suggest pouring out the old oil into a measuring cup to measure how much oil you extracted – this will give you a good idea of how successful you were at extracting the old oil
I was able to extract all the old oil in my Angle Gear which was 425ML – unlike the YouTube videos out there that only extracted 1/3 or 1/2 of the oil in the angle gear which is poor service as the new oil will be contaminated by old oil.
Now refill the Angle Gear with new Volvo gear oil using a fill pump or syringe
Fill up nice and steady because you need to get it full until it drips in single drops – If you fill too fast you don’t want this stuff leaking out the fill hole and spilling everywhere
Once full and there’s a drop of oil dripping out every few seconds install the fill plug with a new copper washer
Torque fill plug to 26 ft/lbs (35NM) – No torque wrench? Once the plug is seated to the gasket just tighten the plug nice and snug. DON’T yank on it and OVER-TIGHTEN, just nice and snug until its tight against the copper washer
Clean area again throughly with brake cleaner or a suitable degreaser to clean off oil residue – do this so when you inspect it every oil change there’s no false leaks because the oil from the service collected dirt around the fill port
Finished! Relax take a break until your ready to do the rear differential
Rear differential is the same steps as the angle gear but a different side you access it from

Rear Differential Guide

Clean around fill port area
Remove 13MM fill plug – clean plug
Insert oil extractor tube
Extract oil – I extracted (450ML) which is the full oil capacity of the rear differential
Refill gear oil until it drips out of the fill port in single drops
Install drain plug with new copper washer – Torque fill plug to 26 ft/lbs (35NM)
Clean area again throughly with brake cleaner or a suitable degreaser to clean off oil residue
Finished! Until next service….

Is this service worth doing if Volvo says it’s not required?

Yes, its worth it. If you’re planning on keeping your Volvo for a very long time. Lubricants are your vehicles mechanical insurance policy when the factory warranty is over. The only thing protecting your vehicles oil protected mechanical parts are the lubricants you choose and when you decide to change them. Let’s look at the cost breakdown of how much this service costs vs. The price of having to replace a failed angle gear or rear differential.

The Angle Gear required Approximately 450ML to fill.

The Rear Differential required Approximately 450ML to fill as well.

I purchased (2) 1 Litre Volvo Gear Oil bottles not knowing how much I would need because Volvo says both components require 1 litre each but this is not true as there is no official oil capacity listed on there specifications. So 1 Litre Bottle of Volvo gear oil was enough to do both the Angle Gear and Rear Differential.

1 Litre of Gear Oil: $37

Angle Gear not including install labour: $2500

Rear Differential not including install labour: $5000

Total parts cost protected by $37 gear oil = $7500

If you change the gear oil every 100,000KM and reach 1,000,000KM you changed the gear oil 10 times. So $37×10 = $370 is the cost of gear oil over 1 Million kilometres of driving.

So you be the judge. 1 litre of Volvo gear oil is $37 and it protects $7500 driveline components! Why would you NOT CHANGE IT???

People disagree and argue that gear oil never has to be changed because Volvo says the fluid will last the life of the component. This is unacceptable. “Lifetime Fill” or “Filled for Life” (maybe they meant lifetime of the differentials…which will be shorter if the oil is not changed). There is no such thing of a lifetime fluid, every fluid in your vehicle eventually needs to be replaced. In todays disposable society vehicle manufactures typically set their drivetrain warranty to match how long they’re “Lubricants” last.

Words of advice and Things to know before doing this service yourself

The Volvo gear oil has the consistency of 5W-30 motor oil so it is not necessary to warm up the oil before extracting or filling the angle gear and rear differential. Therefore even if this service is being done in colder temperatures the viscosity of the gear oil will not have changed enough to make extracting or refilling a problem.

Besides longevity the greatest reason gear oil and other driveline fluids should be changed is to keep everything running and moving as efficiently as possible. Gear oils have an effect on fuel efficiency! The cost of new differential fluid every 80,000KM to 100,000KM could pay for itself over the service life of the lubricant! Remember New Oil is always going to be cheaper than the part it protects! It’s worth it!

Friction > heat = lost efficiency

Gear oil has an effect on fuel efficiency. If the gear oil is never changed the fluid looses its maximum ability to control and prevent friction between the gear teeth which in turn creates heat. Friction creates heat and drag on components which is lost efficiency. Heat is the killer of any component that requires oil. Too much heat can reduce the life of the lubricant, cause damage, leaking seals and reduced component life. New fluid ensures you’re protected because the angle gear and rear differential are air cooled. The gear oil is extremely important because the oil allows the components to run cooler. Low oil in these components will shorten the life of the internal parts significantly leading to earlier failure.

The gear oil smells bad and strong so don’t get it on your clothes or bare hands because it contains olefin sulfide. Wear suitable gloves and protective clothing.

Angle gear fill plug has a magnetic fill plug. The rear differential does not have a magnetic fill plug.

Pouring the extracted oil into a clear measuring cup gives you an exact measure of how successful you were extracting the oil and an opportunity to see the condition of the oil. You might see tiny black particles at the bottom of the clear measuring cup. There should be NO metal particles. The black particles were soft and when rubbed between fingers it smears into nothing therefore there’s no concern.

You can send in your used gear oil in for a detailed oil analysis or just change it at the interval you choose. The detailed oil analysis will provide you in depth information on the actual condition of the gear oil. This information will provide you a good understanding of when to change the gear oil to maximize service intervals and reduce maintenance costs. It’s like a blood test for your vehicles lubricants!

Heat oxidizes oil! Just because the oil is very dark it doesn’t mean it’s bad. The extreme pressure between gear teeth generates heat which eventually turns the oil dark. Notice the rear differential oil is not as dark as the front angle gear? This is because the angle gear handles all the power out of the transmission to the front right wheel and directs power to the rear Haldex system. The rear differential does not have power sent to it all the time. The rear differential only has power sent to it when the Haldex system is engaged. The Haldex system connects the driveshaft that’s connected to the front angle gear to the rear differential. Haldex allows full control over how much power should be sent to the rear wheels depending on driving conditions. Extreme pressure and forces really takes a toll in the angle gear especially if you love to drive hard and launch the car frequently!