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Everything About Car Axles & Drivetrain Seals

The element that seals the connection of a CV axle (driveshaft) to the transmission or rear differential of an automobile is called an axle seal. An axle seal's job is to prevent transmission fluid or differential oil from leaking out. From how they work to the materials and precious metals used in them, we cover everything you need to know about Axles & Drivetrain Seals in this guide.

What Are Car Axles & Drivetrain Seals?

Axles Seals:

It is the front axle shaft seal that prevents the fluid in your differential from leaking out around the axle. So, if you find some issues, then front axle shaft seal replacement is necessary. The differential delivers the power from your transmission to the car wheels. This allows the wheels to move properly. Accordingly, there is a need to lubricate it, as well as your axle. The front axle shaft seal mounts the axle shaft tube or the differential case. 

Drivetrain Seal:

The input shaft seal is also known as the front transmission seal. It makes sure to prevent the fluid from slipping past the input shaft. The input shaft is inserted into the torque converter or clutch disk. It totally depends on whether the car is equipped with an automatic or manual transmission or not. The output shaft seal is also known as rear transmission seal or driveshaft seal.

What Are The Types Of Car Axles & Drivetrain Seals?

Axles Seals

Have a look at three types of axle seals on rear-wheel and four-wheel drive front axles:

  1. Pinion Seal - The pinion seal is situated inside differentials of automobiles. It is designed in such a manner that the fluid does not leak out of the differential. Some automobiles have a rear pinion seal and others have both a front as well as rear pinion seal.
  2. Axle shaft seal - The CV axle shaft seal is a rubber or metal seal. It is situated where an automobile’s CV axle meets the transmission, differential, or transfer case. It prevents the leakage of fluid out of the transmission or differential housing as the CV axle rotates when the automobile moves. There are some vehicles where the axle shaft seal helps keep the axle shaft in correct alignment with the transmission.
  3. Axle cover seal - The axle cover seal is utilized to support the wheels of automobiles. It prevents the lubricant from leaking and keeps the axle component protected from dirt, debris, wear and tear. 

Following are the types of Drivetrain Seals:

  1. Front Wheel Bearing Seals - Wheel bearing seals ensure that the bearings are properly greased and free of dust, dirt, and other pollutants. As a result, if the bearing is not properly maintained, it may fail to function as intended, causing the bearings to fail prematurely.
  2. Axle Shaft Seals - The axle shaft seal is a critical component in your car that stops fluid from leaking from your differential around the axle. It's a flexible doughnut-shaped piece of material attached to a metal or hard rubber basis.
  3. Pinion Gear Seals - The pinion gear seal is found inside car differentials. It is designed to prevent fluid from leaking out of the differential and is placed near the pinion shaft.
  4. Transmission Seals - The front transmission seal, also known as the input shaft seal, stops fluid from slipping past the input shaft. Depending on whether the vehicle is equipped with an automatic or manual transmission, the input shaft is inserted into the torque converter or clutch disc. The output shaft seal, also known as the rear transmission seal or driveshaft seal, keeps fluid from leaking out of the transmission where the driveshaft yoke fits into the transmission. Each axle has two "rear" transmission seals in front-wheel-drive automobiles.

What Are The Important Features Of Car Axles & Drivetrain Seals?

Do you want to know the essential features of axles & drivetrain Seals? Then you have arrived at the right place. Have a look below to know the important features of axles & drivetrain seals:

  • It should have top quality fluid as well as temperature compatibility

  • Keep in mind that it should possess better pumping to pump extra fluid away from the sealing lip and shaft interface

  • It should offer proper protection from contamination and come in two types, labyrinth and flinger seals. 

  • Flanged outer diameter should allow a perfect seal assembly.

  • It should have stainless steel sleeve for high durability under a severe corrosive atmosphere

  • ½ metal: ½ rubber seal on the sleeve which must allow robust assembly and superb static sealing while dissipating under-lip heat build-up

  • Thrust bumper which should provide genuine lip interference and relative positioning. The shaft guide should prevent seal damage during shaft installation

How Do My Car Axles & Drivetrain Seals Work?

Are you searching how the axles & drivetrain seals work? Then all you have to do is to have a look below and then you will be able to understand everything.

Axles Seals:

The axle seal is a flexible seal that rides on the axle and keeps the gear oil with the assembly and from leaking out. The flexible seal uses a small amount of lubricating oil and is housed in a metal carrier which allows it to be pressed against the transmission. 

Drivetrain Seal:

There are two important dimensions of the seals, that is the outside diameter and the inside diameter. The seal which has the perfect outside diameter fits tightly into the recess on the transmission. There is an interference fit in the inner diameter of the seal along with a tiny spring. This is done to keep it snug against the input shaft or the driveshaft.

Now when the input shaft or the drive shaft is inserted into the transmission, then the fluids are locked inside the seal. The seal is designed in such a manner so that it can prevent leakages irrespective of how fast the input shaft or drive shaft spins.

What Are The Symptoms Of Bad Axles & Drivetrain Seals?

Are you searching for symptoms of faulty axles & drivetrain seals? Have a look below to have a clear understanding of the same:


Axles Seals:

Generally, when the CV axle shaft seal fails, few symptoms indicate to the car driver that there is an issue. Have a look at them below:

1.  Signs of leakage around the seal - If there is a presence of leaks, then it is a sign that there is a need to replace the CV axle shaft. When the seal starts to wear, then it can start to leak slowly and start covering the area immediately around the seal with a thin layer of gear oil or transmission fluid. You must get your car inspected by a professional as soon as possible and get the issue fixed.

2.  Puddles of fluid - Another noticeable sign is a puddle of fluid with one of the vehicle’s axle shaft seals. When the axle shaft seal fails, the gear oil or transmission fluid might start leaking from the transmission or differential.

3.  Axle shaft pops out - One major symptom can be that the axle might start popping out of the CV axle shaft seal.


Symptoms of bad drivetrain seals:

 

1.  Leaks around the differential - Drivetrain seals leak frequently as a result of normal wear and tear. You'll notice the leak around the differential once it starts leaking. This could be a little puddle or genuine oil drips. In either case, you should get professional help to replace your drivetrain seals before the condition worsens.

2.  Oil Stains on your driveway - One of the first indicators of a drivetrain seal leak is puddles of oil on your driveway. Oil tends to seep through and spill out as the seal rips and splits, accumulating underneath your car. Because the fluid has had more chance to flow down from your car and pool on the ground after you've been parked for a few hours, these stains will be more obvious. 

3. Dampness around the seal - The only sign of a minor driveshaft seal leak is a moist area surrounding the seal. As with the oil stains stated before, the severity of the leak increases the likelihood of fluid leaking onto the ground. When leaking fluid makes its way into the exhaust system, it can cause a burning odour when the exhaust is hot. The leak could also contaminate your brake shoes, resulting in strange noises and a reduction in braking power.

Which Tools Do I Need To Repair My Car Axles & Drivetrain Seals?

Several skilled auto mechanics have a goal of opening their car repair shop in their career. But let’s face it; if you want to put up an efficient and profit-making shop, then you might need much more than mechanical skills. There are several tools that you might need to perform the car repairs quickly as well as reliably. Auto repair equipment that you will need to repair your Axles & Drivetrain Seals may include:

Tools Needed For Axle Seals:

  • Hydraulic Jack

  • Jack Stands

  • Tire iron

  • Wheel chocks

  • 3/8” ratchet with a metric and standard socket set

  • 1/2” ratchet with a metric and standard socket set

  • 1/2” Torque Wrench

  • Drain Pan

  • Metal Scraper

  • Flashlight

  • Telescoping magnet

  • Towels or rags

  • 24” pry bar

  • Axle seals (2)

  • Brake cleaner

  • Differential fluid

  • Hammer

  • Seal installing/driver kit

  • Seal removing tool

  • RTV silicone

  • ½” torque wrench

  • C-clamp

Drivetrain Seal:

  • Set of Wrenches

  • Hammer

  • Floor Jack

  • Jack Stands

  • Container to catch transmission fluid

  • Screwdriver

  • Seal remover

Which Top Brands Axles & Drivetrain Seals Parts Should I Choose?

If you know which car parts brand suits the best for your Axles & Drivetrain Seals, then it would save a lot of your decision-making time. What we believe is that picking a particular brand would always help reduce the clutter, and would make it easier for the customers to find what they are looking for. That’s why we have listed out some top brands for Axles & Drivetrain Seals below:-

Which Parts Are Related To My Car Axles & Drivetrain Seals?

If you are like most of us, then you won’t know much about the related components of car Axles & Drivetrain Seals. Fear not! Have a look at the related parts of the Axles & Drivetrain Seals.

  • Transfer Case Input Shaft Seal

  • Mounting Adapter Seal

  • Drive Shaft Seal

  • Drive Axle Intermediate Shaft Seal

  • Oil Pump Housing Seal

  • Manual Transmission Intermediate Shaft Seal

  • Side Gear Sea

What Are The Steps Of Changing My Car Axles & Drivetrain Seals?

Keen to know about the procedure of changing the Axles & Drivetrain Seals? Well, we have simplified the entire procedure for you:

Step 1

If you have a new seal that is ready to install, then the spring on the back of the flexible seal should be kept safely. Just be careful that you do not drop this into the transmission or differential.

Step 2

Firstly, you should pry the old seal out of the differential or transmission. If you have a seal removal tool, then it will make your task easier.

Step 3

The installation tool of the Seal and bearing race would come with a lot of different-sized discs. Choose one that would fit into the seal mounting point.

Step 4

After this, the new seal level should be seated on the mount. The seal level should be tapped into place with the seal tool until the seal is fully seated. Just be careful that you do not deform the seal.

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FAQ
If the leaky axle seal is not repaired quickly and the gearbox slips, the transmission may suffer irreversible damage. Driving with a leaking axle seal is hazardous depending on the severity of the leak. Improper axle installation or removal is the most common cause of leaking axle seals.
Axle seals ‌last between 50,000 and 100,000 miles.
Today's automobiles are ‌front-wheel drive, rear-wheel drive, or all-wheel drive. Each vehicle has an axle, which transmits power to the wheels. Each axle is unique in every way and is equipped with two to three seals.
Yes, because the CV axle shaft seals keep the fluid in the gearbox and differential, if they fail, fluid may leak into the transmission or differential, putting the transmission or differential at risk of overheating and damage.
The Axle shaft seal is ‌at the outside end of the axle tube of a semi-float live axle vehicle. The axle seal is ‌at the inboard end of the axle, where it enters the differential, in a truck or SUV with front CV axles.
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John Framigllia
Technical Writer
Our technical writer is known for simplifying automotive parts and services. Intuitive with various vehicles and manufacturers, he knows how to simplify complicated problems.