I filled my '88 M47 with Redline MTL. By tipping the car toward the passenger side I was able to get a full 2 qt in the tranny. It shifts fine and is quiet, but so it was before the oil change. There was some fine metal stuff on the magnetic drain plug so I was glad to have changed the fluid. They say the overfilling will help prolong the tranny's life and I'm all for that. If it had been available here in stores, I probably would have gone with Amsoil Type F.

Volvo do a lot of research and testing so you can't go wrong with their recommendations. That said, I've switched (1983 w/ M46) to Redline's MTL (not MTL-90) and found a big improvement in shifting and OD performance. Redline themselves warn against using their (and presumably anyone's) synthetic ENGINE oil in transmissions - too slippery for proper synchro ring operation.

Simple:

Type F automatic transmission fluid.
Redline MTL
Amsoil Type F

THAT is all. Don't mess with the M47--it is a good trans BUT it is not as strong as the M46 and they are kind of hard to come by on the used market. Mostly $500 and up, while M46 you can pick up anywhere for peanuts because there are so many.

I have used the first two of the fluids. I also tried Mobil 1 10w30 in the gearbox under the recommendation of several people, but it sucked for shifting. Type F is the best for shifting, in my opinion. A good brand like Castrol.

Redline MTL is a great product. I have used it and will use it in the future. It cuts transmission debris to a minimum.

And Amsoil Type F... I've never used it but it has come highly (very highly) recommended.

Like Paul said, don't bother with any gear oil as many standard transmissions take.
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1992 940 wagon, 77k
as well as others.

There are options.

DO NOT USE REGULAR PETROLEUM BASED GEAR OIL.

Volvo asks you to use ATF Type F and perhaps for some years says motor oils of different weights I don't remember what your glovebox manual says. Please check it. I recommend Amsoil synthetic type F, also known as Supershift.

IF you live somewhere semi-warm year round (OK anyhwere but Montana, Minn, Upsate NY, Mich., etc) I would use a synthetic gear oil such as Amsoil Series 2000 75W-90, which really has the same viscosity of a 30-40 engine oil (different scale!). This will really help protect this somewhat delicate tranny. Also the lean and fill technique will keep the vital parts in the oil.
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www.fidalgo.net/~brook4