change rear differential fluid

[sambyanis]

So far I've seen quite a few people recommend that. Maybe they are all wrong too, but do you mind explaining?

Volvo's stuff is a synthetic 75W-90 fluid "API GL-5" right? Same stuff as the Mobil...

I don't think it will be good.

[Nomar]

My mechanic just changed my bevel gear fluid and he said he used Volvo recommended OEM 75-90 'stuff'.

[lookforjoe]

Volvo's description of the fluid for the angle gear is "API GL5, BOT" for the rear differential its "API GL5, low friction" neither of these are transmission fluids. I hope the left over fluid you have from your dealer's changing of the bevel gear is API GL5 BOT and not a transmission fluid. The API GL5, BOT oil is an extra low foaming lubricant while the API GL5 specified for the differential is not. Although the amount dealers change for these lubricants is significant, the quantity required is not. I stick with the OEM lubricants for these expensive to replace components.

Agree 100%

Not worth the price difference for such small quantities, and low service interval.

[Omega5]

Last year I removed the bevel gear and replaced coupling that typically fails, took the oportumity ro perform the service on it as well once i finished, i filled it up with Castrol 75W90 full synthetic oil (didn't even give it a second thought after seeing what was inside) and poped it back in place and way i went. It is now 60,000 km later, and i haven't heard anything from that part of the engine, also no leaks and no problems.

Since then, I also changed one rear drive shaft (broke it while messing around in the snow) changed a rear bearing twice (first one was 75$ internet special, the scond was from the dealer at 260$), i have also blead my brakes and replaced the fluid completely, i have flushed the rad, and replaced the damn fuil fill hinge twice.

Now i am about to change the rear differential oil, i see a lot of talk (As usual) about which oil to use ... once again, i will go with my gut feeling and stick with the full synthetic 75W90. Way i see it, is if all it is is gears and bearings it should be fine, now if that oil is shared (like what Honda does, it is used ny the AWD clutch) that 75W90 is definatelly not the right oil.

Any comments?