How to Check the Condition of a Used Final Drive Before Buying

(An educational, step-by-step guide for anyone purchasing used OEM final drives in South Africa)

A final drive isn’t just another excavator part.It’s the heart of your machine’s travel system — and one of the most expensive components you’ll ever replace.

Buying used OEM final drives is one of the smartest ways to save money… if you know how to check their condition properly.

Because let’s be honest:A final drive can look fine on the outside and still be an expensive disaster waiting to happen.

This blog breaks down exactly how to inspect, evaluate, and verify the condition of a used final drive before you hand over a cent.

Let’s get started.

1. Start With Identification: The OEM Part Number Matters

Before anything else, verify:

• OEM brand (Volvo, CAT, Komatsu, Hyundai, Doosan, etc.)

• exact part number

• model compatibility

• left vs right side

• reduction ratio (very important)

• generation/version (dash-3 vs dash-5 etc.)

If the seller cannot provide:

• the part number

• compatibility list

• or a clear ID plate

Walk away.

OEM numbers remove 90% of the risk.

2. Visual Inspection: The First Layer of Clues

A quick visual check can reveal big problems.

Look for:

• cracks in the housing

• weld repairs (major red flag)

• missing bolts or damaged threads

• fresh paint hiding deeper issues

• worn sprocket holes (on integrated drives)

• damaged connectors or wiring (on travel motors with sensors)

A final drive should look used — not abused.

3. Check the Input Shaft and Mounting Flange

The input section of a final drive tells you a lot about its history.

Rotate the shaft:

It should turn smoothly without:

• grinding

• sticking

• excessive stiffness

Wiggle the shaft gently:

Tiny movement is normal.Excessive play = worn bearings.

If the shaft feels loose, that final drive is already halfway dead.

4. Inspect the Gearbox Oil (If Accessible)

This is one of the best ways to judge internal condition.

Ask the seller to:

• remove the inspection plug

• drain a small amount of oil

Red flags in oil:

• silver glitter → metal wear

• thick black sludge → overheated oil

• burnt smell → extreme internal friction

• milky colour → water contamination

Oil never lies.If it looks bad, the gears and bearings inside are suffering.

5. Check for Metal on the Magnetic Plug

Nearly all final drives use a magnetic drain plug to catch metal particles.

If the plug shows:

• a few tiny shavings — normal

• a light paste — acceptable

• chunks, flakes, or thick paste — walk away immediately

Heavy metal contamination = bearings and gears are eating themselves alive.

6. Rotational Smoothness Test

Rotate the sprocket hub by hand (or the flange if sprocket isn’t included).

It should feel:

• smooth

• consistent

• stable

If it feels:

• notchy

• bumpy

• gritty

• uneven

The internal gears or bearings are damaged.

7. Check the Motor Port (Travel Motor Interface)

The motor side of the final drive should be clean and undamaged.

Look for:

• broken bolt holes

• gouged surfaces

• damaged o-ring groove

• uneven wear

• oil seepage

If the mounting face is damaged, the motor will not seat properly — and you’ll end up with pressure loss or leaks.

8. Pressure Testing (The Gold Standard)

A proper used OEM supplier like Vikfin pressure-tests final drives before selling them.

During a pressure test, technicians verify:

• reduction function

• gear noise

• bearing performance

• oil movement

• seal condition

If the seller doesn’t offer test results or refuses to test the drive:Don’t buy it.

Testing separates genuine used OEM quality from scrapyard gambling.

9. Seal and O-Ring Condition

Final drives rely heavily on seals.

Damaged or hardened seals lead to:

• oil loss

• water ingress

• catastrophic bearing failure

Ask the seller:

• have the seals been replaced?

• are they OEM-spec?

Cheap aftermarket seals can ruin a good final drive.

10. Ask About the Machine it Came From

A good used OEM dealer keeps this info.

Important details include:

• hours on the donor machine

• reason for dismantling

• model and serial number

• working environment (mine, sandpit, construction site, quarry)

Final drives from mining machines usually have harder lives than drives from civil construction, even at the same hours.

11. Warranty or Guarantee

Even used parts should come with some form of guarantee.

Reputable suppliers like Vikfin typically provide:

• limited test warranty

• immediate operational guarantee

• return/refund if incompatible

If a seller offers no guarantee, be cautious.

12. Compare Prices to Market Rates

Used OEM final drives sit in a certain price band.If the price is too low, the unit may be:

• flooded

• cracked

• previously rebuilt poorly

• internally damaged

• misidentified

If the price is too high, you might as well buy rebuilt or new.

A quality supplier prices based on:

• condition

• testing

• brand

• demand

• stock availability

13. Check for Superseded OEM Numbers

Sometimes the number on the final drive is outdated.

Ask if:

• the number has been superseded

• the replacement number is compatible

• your machine requires the new version

Vikfin checks supersessions automatically — many private sellers do not.

14. Evaluate the Supplier

This might be the most important step.

Choose a seller who:

• understands excavators

• matches part numbers correctly

• provides tests

• inspects all stock

• offers honest condition reports

• responds quickly

• has a reputation for quality OEM components

A great part from a shady supplier is still a bad buy.

Conclusion: Testing, Inspection, and OEM IDs Protect Your Pocket

A final drive is too expensive to buy blindly.

When you check:

• OEM numbers

• oil condition

• magnetic plugs

• seals

• shaft play

• rotational smoothness

• pressure test results

…you ensure you’re getting a unit that will last, not a ticking time bomb.

Used OEM final drives from reputable suppliers like Vikfin give you:

• long lifespan

• excellent reliability

• a fraction of new OEM cost

• immediate availability

But only if inspected correctly.

Learn the checks.Protect your investment.Make your excavator work, not waste money.

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