UKKid35

I've just realised I've used the wrong grade oil, although it was fully synthetic it is rated only API GL4 rather than API GL5. It must be less harmful that the stuff that came out, but how urgently should I change it?

This is what I thought I was buying
http://www.morrislubricants.co.uk/pr...?v06c41q7p6=FH

This is what I was given
http://www.morrislubricants.co.uk/pr...v06c41q7p6=ELM

Should have checked more closely....

Drmark

Paul,
Was it you who had the spill when changing the engine oil? If so, you don;t much luck in this dept do you!
No idea what the difference is between the two specs - but I am sure someone will.
Cheers
Mark

UKKid35

Yes, but I didn't spill a drop this time!

However I used 8mm tubing to fill, which took forever, not realising that I could have used a much larger guage without problems.

Garth S

Doug Hillary has an excellent piece on lubricants - where GL 5 is specified: As the transmission and differential share the same lube, the difference must be in the lube film shear and/or pressure rating req'd by the diff gears. LSD also has its unique needs, generally met by most syn. GL-5s.
Before exchanging the lube ( see how nicely I avoided "draining" ), why not contact the Lodexol tech. service line and get their advice? - perhaps they have a solution ... to be taken or added.

GlenL

GL5 is a "heavier duty" lube than GL4 and protects when there are higher pressures between the gear faces .

Not a crisis; you didn't put tranny fluid in the engine. I'd change it in a week or two and call the first round a cleaning step.

Daniel Dudley

You can ruin a diff in less than 5000 miles. Change asap and don't flog it. Ask me how I know.

UKKid35

Thanks Daniel - that's hard advice to ignore.

UKKid35

Thanks for your encouragement to change, it's so much easier second time round! And now I feel much more confident driving the car.

I persuaded the supplier to sell me the correct oil, API GL5 fully synthetic 75W/90, at half price.

The magnets had still managed to collect a little debris, but not too much, and of course the oil I drained was completely clear.

I used a 2 metre x 12.5mm tube to fill, and my gf got much less bored holding the funnel as it took only a few minutes to fill this time...

m21sniper

That's a good GF you got there UKK.

Doug Hillary

Hi,
Paul - you were wise to change. It is most unlikely that any damage has occured as the oil you used was a synthetic so it would have been well formulated - just not for a 928

Some synthetic gear oils are now both GL4 and GL5 compliant due to the newer additive packages available. GL5 has a greater "shock loading" ability at any viscosity and this is needed in the 928

The PSD does not need a special LSD additive or oil

Regards
Doug