Transmission oil

verytricky · 09-10-2005, 10:15 PM

I am sitting here holding a bottle of Volvo Penta Synthetic Transmission Oil. It is the official stuff that James Sydenham puts in the gearbox.

It is 75w90

I have found nothing else except 75w90 as a replacement.

ATF? as previously suggested? It is also 75w90 which is thick.

Could I run ordinary engine oil. Like 5w15? It would definately thin the oil and this would get more power?

Matt · 09-10-2005, 10:35 PM

ATF=75W90? I don't believe you.

Jon Fuller · 09-10-2005, 11:01 PM

ATF (Automatic Transmission Fluid) is generally #5 grade

jw. · 09-10-2005, 11:09 PM

The Volvo oil is synthetic gear oil... GL5 spec. I put some in the diff of me Jeep today.
Err, that's not quite true it was Castrol's equivalent cos Volvo stuff is a really silly price.

Jon Fuller · 09-10-2005, 11:11 PM

so what 'weight' is the volvo synthetic gear oil?

jw. · 09-10-2005, 11:18 PM

75w90

Jon Fuller · 09-10-2005, 11:25 PM

OK,
the purpose of this exercise, is to run a lighter grade oil to reduce component drag within the drive assy and 'free up' some ponies.

jw. · 09-10-2005, 11:40 PM

Quote:

Originally posted by Jon Fuller
OK,
the purpose of this exercise, is to run a lighter grade oil to reduce component drag within the drive assy and 'free up' some ponies.

Yeh, I know. I'm not sure there is much to be gained using thinner oil though. I suppose there is some pumping loss at the pinion gears but the rest is just spinning in the oil. The dpx is reckoned to use about 10hp. I'm not sure where it all goes!

Are you in stealth mode tonight JF?

verytricky · 10-10-2005, 12:09 AM

Matt,

just quoting what I have been told!

I do not know myself.

I can say the 15w90 is thick stuff, and it burns if you dont wash it off you fingers!

JW: you recon the DPX only costs 10HP?

jw. · 10-10-2005, 12:14 AM

I think that's what Volvo reckon. I'll check.

jw. · 10-10-2005, 12:17 AM

Oops, sorry, 13hp.

Jon Fuller · 10-10-2005, 12:23 AM

That's still pretty low, Mercruiser seem to think about 25hp @ 400 ish SHP for a B1. puting the power through two right angles ain't ideal

jw. · 10-10-2005, 12:39 AM

That's a lot. Maybe explains some of the overheating problems and the need for showers in some applications.

That's the heat from about 18ish electric fire elements...feckinell.

BluFin · 10-10-2005, 05:51 AM

Think about the Thermal stability of the Oil if mixing, can have adverse affects and cause a breakdown of the oil
Both should, I suspect be HTS Oils.

verytricky · 10-10-2005, 07:09 PM

Quote:

Originally posted by Jon Fuller
ATF (Automatic Transmission Fluid) is generally #5 grade

The only 'grades' I could find were these: I dont think this is the correct 'grade' to #5 as in your example aboe.

5WT = 0w0
10WT = 0w10
20WT = 5w20
30WT = 10w30
40WT = 15w40
50WT = 15w50
60WT = 20w60

Matt · 10-10-2005, 08:45 PM

Dexron III ATF is, I think 0w20. But, if you can get a 20 weight fully synthetic engine oil, it will be much better at load bearing than ATF.

Matt · 10-10-2005, 08:49 PM

The "weight" of the oil is the bit after the w. So, 40 weight is always going to be something-w-40, and should be matched to the engine's needs. The bit before the w relates to the cold temperature viscosity, or in noddy terms, the lower the better.

CB1 · 10-10-2005, 08:55 PM

Try royal purple gear oil. Very thin but very good!!

jw. · 10-10-2005, 10:27 PM

Quote:

Originally posted by Matt
... if you can get a 20 weight fully synthetic engine oil, it will be much better at load bearing than ATF.

Not being smart, Matt. Do you have info to back that up?

jw. · 10-10-2005, 10:29 PM

Quote:

Originally posted by CB1
Try royal purple gear oil. Very thin but very good!!

CB1 any info on this oil?