Change oil in diff. and gearbox?

Hi everyone, I have Volvo fh trucks 10-11 pates and was wondering how often do you change oil in diff. and gearbox? Thanks,

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It depends on whether you are using mineral, semi syn or fully synthetic oil in the transmission.

300,000 km

It all depends on your operation, the best way to tell is to drain a bit and send it off for analysis,

Oil does not go off, it gets overwhelmed by contaminants and in a closed system such as a gearbox or differential, contaminants mean wear metals.

Analysis is the ONLY reliable method of determining oil change intervals.

newmercman:
It all depends on your operation, the best way to tell is to drain a bit and send it off for analysis,

Oil does not go off, it gets overwhelmed by contaminants and in a closed system such as a gearbox or differential, contaminants mean wear metals.

Analysis is the ONLY reliable method of determining oil change intervals.

Most do not have a closed system anymore eg one way breather valve.A top hat seal.
Most have an open vent system that allows expansion but also allows water ingress as the axle cools sucking crap into the axle banjo.

Also causes hub seal failure due to breather blockage and pressurising the axle while in operation.Once upon a time you pulled a diff plug and it had a vacuum behind it now the oil is at atmosphere and black as your hat after 100.000 km.
Used to change oil on Rockwells after 500,000 km and it was as clear as honey.
But of course that dont sell axles does it.
Gearboxes had the same idea but again it does not sell gearboxes does it!

So the breather tube doesn’t have a one way valve where it goes into the housing, hmmm, that’s a bit daft.

newmercman:
So the breather tube doesn’t have a one way valve where it goes into the housing, hmmm, that’s a bit daft.

Not daft at all if you want to sell axles.

Or oil!

True story

In the supposedly bad old days i worked for a mid sized haulier who maintained exceptionally well, but worked them hard and fast at full weights, he always said oil was cheap repairs and downtime were not.

Engine oil at 15k miles, gearbox and axle oils every third service so 45k miles, on the usual overspecified drivetrain of ■■■■■■■ Fuller Rockwell.
No prizes for the failure rate over the average 7 years from new they were kept.

Learned a lot there, and similarly always overmaintain my own cars, no prizes for the failure rates here either.

Make sure you use the correct grade of oil or your going to do more damage than good, I’ve got an old fh and always changed gear oil and diff oil periodically not100% on mileage but I know it’s over serviced,

at the very least every mot mine get done

as previously said the type of oil can be crucial, some oils cannot be used on brass bronze type bush or bearings, and as also said oil is always cheaper than any repair and downtime.

hotel magnum:
as previously said the type of oil can be crucial, some oils cannot be used on brass bronze type bush or bearings, and as also said oil is always cheaper than any repair and downtime.

Who the hell uses brass bronze bushes or bearings any more?
You still driving a bloody Trojan?

I change the engine oil 3 times a year and gearboxes and diffs once a year Scania 8 and 6 wheeler tippers doing between 80,000 and 100,000 Kms a year

Volvo recommend changing the diff oil at 800,000kms on my trucks.

Going by my experiences over the years I would say diffs as tough as they come, its the gearboxes that need looking after, but I have noticed the newer motors take quite a bit less diff oil then before, I would guess that the changes date from mineral to syn.
Daf used to be every annual Y service then in 2006 they changed it to every Y3 for trans oils, gearbox oil was as black as they come from then onwards.

hodgeturbo:
I change the engine oil 3 times a year and gearboxes and diffs once a year Scania 8 and 6 wheeler tippers doing between 80,000 and 100,000 Kms a year

Bet you get a christmas card off the Saudi royal family every year dont you!

This is the form I work from, I also get my engine oil sampled when it’s drained. I drop my oil at 50,000kms as my operation is a bit heavy duty.