960 Wagon -96 differential with automatic lock, oil change

[KAIHUUHTANEN]

Hello, I tried to change the differential oils without success.
The multilink suspension covers the differential bottom so I finded a hatch inside of car. I think this hatch is mentioned to access a fuel tank sensor but it helped me to locate a level plug from the front side of differential.
The level plug is almost impossible place to open. I tried with a socket wrench including a joint under car but angle is difficult. Do anyone know any helpful hints to do the job? My plan was suck old oils with a manual pump and then refill it sameway, because there weren`t a drain plug. / Kai

[ivor940]

Hi. none of the differentials have a drain plug on 940s, but you can remove the bottom bolt on the aft facing cover of the diff, and the oil will drain out. Do make sure first that you can open the level / fill plug first so you can refill the diff ( Though you could remove an upper bolt on the cover and refill through the bolt hole the correct amount of oil). The same advise applies to the gearbox ( checking the fill plug opens before draining the gearbox )

ivor940

[Peter Milnes]

The amount of oil in the differential is 1.35 Litres (locking differential) and 1.5 Litres for standard. The reason for no drain/fill plug is that the unit is sealed for life as it uses fully synthetic oil which Volvo recommend not to replace during the life of the car. The only way to replace the oil is through the speedometer/ABS sensor plug but the internal clearance is very critical. Should the unit require servicing where the rear cover is removed the fresh oil is put into the unit with the nosepiece downwards then the cover is replaced and bolted up with new gasket (Unit is off the car for servicing).

All the best, Peter.

[KAIHUUHTANEN]

I`not willing to take off the differential unit, because then I should disassemble the multilink suspension also. I will check first can I open the level plug to see how worn oil looks like. Then if needed I´m ready to take off the speedometer sensor. I just changed the automatic transmission oils and they were totally run out(10 years, 183000km). That why I assume that the differential oils can also need changing. Thanks, I let you know how did I manage. It might take couple of weeks. Cheers ,Kai

[Peter Milnes]

Kai, my recommendation re gearbox oil (fully synthetic ATF) is to flush replace every 100,000 miles (160,000kms). The differential oil should also be flushed/replaced at this interval. Both oils are fully synthetic. Volvo do not recommend any change interval for gearbox and differential oils! You should be able to remove the cover without much difficulty, or removing one of the bottom cover bolts should drain the oil sufficiently. Replace the bolt and remove one at about the right level to refill through.

All the best, Peter.