|Though Often Overlooked, These Two Elements are as Important as
Changing the Oil - |
There has long been intense focus on frequent engine oil changes every
3,000-5,000 miles. In truth, oil change intervals can be as short as
3,000 miles or as long 15,000 miles on some new cars. With the
high-performance reserves of Mobil 1™ synthetic motor oil, you can
have the confidence to go the full mileage or time frame recommended by
the vehicle manufacturer*.
With all this attention being paid to engine oil and filter changes,
what about the rest of your vehicle’s driveline — the transmission and
axle? How many of us never give transmission and axle service any
thought? Regardless of what manufacturers say about “life of the unit”
lubrication (no fluid changes), clean lubrication beats the socks off
dirty lube any day. Clean fluid provides a clean oil wedge between moving
parts. It also keeps dirt and debris on the move and away from those
moving parts. Clean fluid is also kinder to seals.
Transmission and axle fluid changes should happen at the same time —
every 30,000 miles — including the filter. And while your vehicle is in
the air, it’s a good time to inspect everything underneath, like the
Universal joints, driveshaft, suspension bushings, ball joints, shocks,
struts, fuel and brake system hoses. Anything suspect should be replaced.
Drive axles do a tremendous amount of grunt work and it shows in the
condition of gear lube when it’s time for a change. Because gear loads
and pressures are high in differentials, they tend to run hot — around
300° Fahrenheit — especially if you’re climbing a hill with a heavy load
at highway speeds. This is why drive axles should be serviced every
30,000 miles. And when you service, follow the manufacturer’s
specifications with the correct viscosity. If you have a locking
differential, don’t forget to go with a friction modifier for smooth and
consistent clutch engagement. While you have the differential cover off,
check all seals and axle bearings. If your vehicle has over 100,000 miles
and has never had axle bearings and seals replaced, do it now.
Whether you’re working with an automatic or manual transmission, service
should be performed every 30,000 miles. Though manual transmissions used
to take heavy weight gear lube, today’s newer manuals with tighter
tolerances take automatic transmission fluid for easier shifts and cooler
operation. Again, check with your manufacturer to see what type of
lubricant is recommended.
Whenever you perform automatic transmission service, remember both fluid
and filter should be changed. Follow the manufacturer’s recommendations
on fluid type and capacity. If you’re wondering where the dipstick is on
some applications, it has been phased out and replaced with a service
port via the pan or case. This approach to fluid fill prevents
overfilling and fluid foaming. Some automatic transmission filters use an
o-ring between filter and case, so make sure the old o-ring has been
Before you begin tackling any DIY maintenance or repair job, however,
your primary concern should be safety. Following a few safe work
practices and investing in protective equipment – like gloves and proper
eye protection – should help reduce your chance of injury.
Here are some more suggestions that you may find useful:
*We recommend you follow the oil and filter change
frequencies shown in your owner's manual. Generally, this means changing
your oil every six months when using Mobil Super™, Mobil Super™ High
Mileage and Mobil Super™ Synthetic motor oils, and every year when using
Mobil 1 or Mobil 1™ Extended Performance synthetic oils.
Most drive axle assemblies today have a removable pan, which
makes service a breeze. Be prepared for installation with a fresh gasket
and sealant. If you have an older removable carrier type drive axle found
in Fords and some GM vehicles, removal is more involved. You can remove
the differential or knock one of the bottom studs in (with a lock nut
attached) and allow it to drain. Lube can also be siphoned out.
Because axle lube has a strange way of finding even the tiniest
leak path, surfaces must be clean and free of scoring. Ideally, you will
have a composition silicone and steel gasket if available. Otherwise, go
with the best gasket material available.
Axle service is the time to check for leaks and correct them.
This 8.8 integral carrier drive axle has a leaking pinion seal, which
must be replaced. You can’t just change a pinion seal because the ring
and pinion have to be set up all over again. When the drive flange or
yoke is removed, preload changes and must be set again.
When you are performing drive axle service, this is the time to
replace axle bearings and seals. Some axle bearings are pressed
on, which calls for a hydraulic press.
For seal installation to be leak free, a very thin film of sealant
is applied to the perimeter to fill in any irregularities.