Alfredo Ruiz asked:

>The Bently book and other references specify the final drive fluid as:
>90W "hypoid type" GL5. I have a gallon of 90W GL5. My question is
>this: Is "hypoid type" a synonym for a GL5 service rating? or is there
>something different about a "hypoid type" GL5 oil?
>
>BTW, the engineering term "hypoid" refers to a gear tooth shape in
>which the gear teeth slide across each other as in a worm gear.
>In contrast, an "involute" is a gear tooth shape in which the gear
>teeth roll across each other without sliding as in clock gears.

Alfredo, BMW have issued a Service Bulletin (i think it was in '93, i can look up the bulletin if anyone needs it) that stipulates new synthetic final drive lubricants for all BMW models.

There are two types of oil, depending on if you have a standard 'open' diff or a Limited Slip diff (LSD).

Oils for standard (open) diffs: BMW Synthetic OSP

Castrol SAF-XO

Oils for Limited Slip diffs: BMW Synthetic MSP

                                Castrol SAF-XLS
                                [unknown brand] VS-700

Gunnar Elmgren, Stockholm, Sweden
BMW Club Schweden #1436
'71 1600-2 Vollcabrio, '75 2002tii, '90 M5(all with synthetic diff oil.)

Gunnar Elmgren                            ______'
AS/400 Software Support, IBM Sweden     o/______\o
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