Axle oil - Which type?

According to my 740 Haynes manual:

* Rear axle without limited slip differential: Hypoid gear oil,
Viscosity SAE 90 EP to API GL5 or GL6.
* Rear axle with limited slip differential: Volvo oil (No. 1 161 276 -
9.)

The two questions I have are:
1) How do I tell if the differential on my car is limited slip?
2) What is Volvo oil (No. 1 161 276 - 9.)? Is there an equivalent?

The cars are '86 740 GLE and '88 760 GLE (V6.)

Also, I couldn't find the place to fill the diff. oil on the 760.
Supposedly there is a nut on the front of the differential but I could
not find it.

Thanks.

 

Hi try Austin or Len at Carson and Murphy OR John Johnson our ex president
hope to see you at the next meeting 1st Wednesday of the month check out
the url above .these guys are Volvo through and through if they don't know
no one does .I think if you jack up the rear wheels and place the car in
gear try holding one wheel to stop it and see what happens both go in the
same direction if its a limy and opposite if its non limited diff ,better
still check the guys who know .

 

With the car in neutral, handbrake off, block front wheels, jack up one
rear wheel and try to spin it. If it spins you don't have a limited
slip differential. Also there should be a tag on one of the diff cover
bolts outlining the need for special oil if the car is equipped with a
limit slip. (Very few are)

Volvo (No. 1 161 276 - 9.) is just differential oil with the additive
required for limited slip differentials.

The fill plug is on the left side, about halfway up.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)