Boxster gearbox stiffer after oil change

[chris7676]

So I had the box oil changed at my 986 S at a reputable indy a few months ago. The result is actually the stiffer gear change than it was (it was pretty decent but not brilliant). It has got a bit better now after around 600 miles but still not good as before. The car has 92k miles. Is it a common situation? Would another oil change make it better? Or perhaps use any 'special' oil? I only assume they have used a suitable but don't know the details as paid for parts & labour (£60)...

[Trev450]

Have you spoken to the indy that did the work?

[chris7676]

Not yet, wanted to get opinions whether it's typical.

[Maersk]

Is it the right spec. oil?

[chris7676]

I could only assume so. I guess no one else had a similar experience then ?

[PGM]

Had a similar problem recently with my Subaru Legacy, correct oil also.

Stiff when cold in 1st and 2nd but OK when warm. Seems to be easing with mileage stragely.

[NTY]

I experienced stiff shifting from 2nd to 3rd gear after changing my GT3's transmission oil to Mobil 1 SHC 75W-90. I intially thought it was because I did not put in the designated Mobil PTX. Strangely, the shifting improves with time and it is now as smooth as before.

[wildoliver]

Sorry to awaken an old thread but what was the update on this?

I changed the oil on our Box S yesterday to try to improve the cold shifting (shifts nicely when warm but tight when cold as per all Porsche/high performance boxes) and to be honest it's worse than before. Fine when warm though.

Is there a particularly good oil to use, don't mind changing the oil again by any means just don't want to cause wear to the box.

[chris7676]

The update:
After the time, now it feels similar as it did before, which is pretty good rather than perfect. Strange things these boxes

[wildoliver]

Sounds like we are in the same boat then.

I'm sure I recall an oil used by 944 owners to cure the noisy and balky boxes, I think it was Swepco or Red line?

[littlejohno43]

Opie oils do the oil at good prices I you need the right spec as the baulk rings can't handle Iraq and stiff changes occur

[hartech]

If there are additives like molybdenum in the oil it can slow the synchromesh from doing its job (basically because it is too slippery to enable the cones to slow or speed up the two mating parts together).

As it wears the quality of those additives deteriorates - so it this it what has happened I would recommend a bog standard gearbox oil rather than anything fancy.

Baz

[browno]

What you will be feeling is normal - your old fluid will have sheared (thinned down) over the miles due to the gears chopping up parts of the oil - so it will have a lower viscosity when drained. When you have put back in a new, (hence thicker) fluid, it will initially feel a little stiffer, but will settle with miles.

As someone who develops oils for a living - this is what I would expect, so don't worry - as long as you have used the correct Mobillube fluid, that Porsche specify, then all will be fine