I have just replaced the transfer case lubricant on my 2003 Toyota RAV4. I followed the advice of the Haynes manual and used SAE 75W-90 gear oil. I have just looked in the handbook that came with the car and this says that SAE 85W-90 HYPOID oil should be used. Is the use of normal gear oil in the place of hypoid likely to cause problems? Should I change the oil to hypoid or will it be OK left as it is? (I used hypoid oil in the rear diff - the Haynes manual got that right). Thanks.
Normal gear oil in place of hypoid - problems?
May 02, 2005
6 Replies
I would not expect ordinary gear oil to be a suitable replacement for hypoid if that's what's specified, but others may know different.
Rob Graham
It's not. Hypoid oil has extra additives, so the oil doesn't break up under the higher sliding forces between the gears, found in hypoid gearboxes. Personally, I'd put the right oil in.
Hypoid gears, that is gears which have curved teeth which have a sliding engagement, need Extreme Pressure [EP] oil. If your 75w/90 oil is actually a
75w/90EP, and it would be unusual if it were not, then you have the correct oil.Huw
The oil bottle says that it is API GL-5 rated, but doesn't mention that it is "Extreme Presuure". Are they the same thing?
Both GL4 and GL5 ratings say that the oil is an EP and therefore suitable for hypoid gear sets. Sleep easy tonight :-)
Huw
GL-5 is the uprated version of GL-4 and should be suitable for EP and sliding gear applications including hypoid boxes and diffs. Does it have that disticnctive smell - if so that's the phosphorus and sulphur additives and it will be fine.
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