Running in rebuilt 915: When to change oil?
 

I have just had the 915 in my '76 Carrera 3 rebuilt - new synchros, some dogs and bearings, plus a Porsche short shift.

My mechanic, who is OPC trained with 15 years experience with Porshes, reckons the standard gear oil he has used will be fine for 20K miles. However, I am tempted to run the gearbox in, then change to Swepco 201.

Any feedback on whether my approach is worthwhile? If so, how should I run the gearbox in and how many miles this will take?

Al G

I've never rebuilt one, but I'd be inclined to think that 500-1000 miles and then I would change the fluid. That way, you'll be able to drain out any metal swarf (particles, etc.) that may have been hiding in the tranny from the rebuild. You'll also be able to check your magnetic drain plugs for junk.

Cheap insurance if ya ask me...

-BG

I would run the trans for about 750 miles then swap over to Swepco. I had thought to give you a lower mileage at which to switch, and hopefully others will chime in here, but the 750m mark will probably be a point where most of the new swarf will have come clean and you can pull this particulate out with the change.

Another method is to swap out at 500 then at 1500 again. This rids the trans completely of dino oil and completes the transfusion to Swepco.

Other points:
= Remove the fill plug before the drain plug.
= If you can find a magnetic plug for the fill plug, put one in.

John

Al,

I ran my rebuilt for about 1000 miles then drained and added the Swepco. You'll notice an improvement in the shifting anyway at around 1000 to 1500 miles. Less stiff and balky as everything seems to settle in a bit.

Dan O
84' 3.2 Targa

Swepco is dino oil, just a different brand. Pretty conventional stuff, actually. But great oil for Porsche synchros, so they say. Also, do not use a magnetic drain plug for a fill plug, you want any particles to stick to the bottom of the oil pool, not be suspended at the top. This would be the reason why no manufacturer ever put one in that location. :cool:

Many thanks to you all - looks like a souple of weekends worth of driving!

Al G