I have to fix a leaking rear differential and was wondering where I can get the gasket from for a '91 740. I have looked at a couple of places, including IPD, and haven't been able to find anything. Also when I do find one do I need to torque it down and if so how and ft/lbs? Thanks

Which gasket? Do you mean the gasket for the large cover plate on the back? In that event, either make your own or use RTV.

Yeah that back cover is leaking from what I can tell, isn't there a gasket I can buy? Is RTV that sealant that comes in a tube, if so how well does that stuff really work? I would think I would be better off buying a real gasket if I can.

There's always the dealer... it's not an expensive gasket, <$10 if I recall correctly. And RTV silicone does work fine, often the cover comes off leaving the gasket behind, intact, then I just put a skim of RTV on the cover & reuse the old gasket. I expect the leak is from the cover itself rather than the gasket. Depending on your climate they do rust through. In Nova Scotia, Canada, 15 years from a diff cover is quite an accomplishment unless enough other things are leaking to saturate the bottom of the car with oil... Rarely do the gaskets fail in my experience.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf

The '91 used an alloy cover, not steel, and should not rust like the old ones did.

Gaskets probably could be find in shops working on american cars, too - the axle originates from a widely used Dana design.

Martin
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'65 121, '73 165

Good to know, Martin - thanks! I know the IRS cars (760, 780?) had an alloy cover, does that apply to the live axle as well?
-Chris
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf

Volvo began using the alloy cover in ABS and/or IRS equipped cars only. From '89, all 700 cars should have it. Similar applies to 200 cars - first in ABS cars only, from '92 in all models.

The new cover not only took care of the previous rust problems - it also offered a more accurate speed sensor mount and thus eliminated the need for shims. This is why ABS cars, with more demanding sensor setups, got it first. After a few years ABS grew more common and all models had the new sensor setup no matter if brakes were ABS or not.

This also is a good reason not to replace the gasket with rtv - speed sensor will get closer to the sensor wheel when the paper gasket is missing. I don't think it would interfere with the wheel but this could be an expensive lesson.

Martin
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'65 121, '73 165