I will be posting a starter repair/cleaning tutorial for the Porsche Cayenne. I bought a 2006 S a few months back and it had the startup whine that I believe is common to this vehicle. I have replaced the old starter with a Chinese $130 job, but I don't trust that the starter will last.
I was amazed that no one had posted a DIY for this since the new Bosch starter is so **** expensive. As of right now I have most of the starter disassembled (which was not difficult except for one part that I can't figure out). As I clean and put back together I will post pics and advice. I found a few sites where you can get starter parts, mostly in Great Britain. I used a parts company called saverepair.com. Unfortunately, Bosch doesn't supply a lot of parts specific to this starter. The starter number is 0 001 125 025. Other good reference sites are aspwholesale.com, https://en.as-pl.com and this parts breakdown helped TREMENDOUSLY http://www.woodauto.com/Unit.aspx?Man=BOSCH&Ref=0001125025 (which wood auto was my second choice for parts but they cost a bit more.)
What I could order from saverepair.com were these parts.
|bsx208-209||Bosch Starter Motor brushes 5.8 mm x 18mm x 14.6mm.||€3.60||€3.60|
|wsbu9016||Starter Bushing 10,08mm x 14,04mm x 9,90mm Rear bushing for Bosch,Front Bushing for Valeo D7E, and Centre for Ford Motorcraft.||€0.55||€0.55|
|wsbu9022||Starter Bushing 28,47mm x 32,30mm x 10,00mm. Front bushing used in Self-Supported Bosch starters.||€1.72||€1.72|
|wss0020||Starter Solenoid for Saab 9-3 Turbo 9-5 Turbo 900 9000 Opel Astra F Corsa A B Kadett E Vectra A B Lancia Fiat and more.||€18.00||€18.00|
Pretty cheap parts as you can see. When I received the parts I was a bit concerned that the solenoid wouldn't work (I basically picked it by cross referencing starters that were close to the number range and had the same type of connectors). This solenoid is a bit larger than the old one, but the screw holes match up perfectly. I have never replaced bushings or brushes before, so this will also be an adventure I'm sure.
On a side note, I REALLY wanted to replace the main bearings on the starter, but there are a few things I can't figure out. There is a part called the bendix that has the gear at the end that also holds the bearings. It is also attached to the stationary gear and a spiral gear shaft. I can't figure out how it all separates. If I did, I could just replace the entire bendix with the bearings on it. I'll see if I can attach a pick of what I'm talking about. If I can't get them separated I think it will be fine as the bearings still turn.
I believe the major points of wear on the starter is the bushings. There is wiggle and play on the shafts on the bushings, which is probably why the starter was whining.
One more thought on removing the starter itself. There are write-ups for that so I won't delve, I will say, it is a relatively easy job of removing parts to get to it, but it does take a lot of time. I was able to remove the starter also without disconnecting coolant lines. I also added a pic of me after ripping the engine apart, with a much rewarded pipe blend called "quiet nights" (completely irrelevant to the post, ha!).