This task rose to the top of my list in the last few days, with a couple of near non-start situations. Couldn't put it off any longer...
Removed the starter (easy to say than to do!!) out the via bottom after removing the transmission under-shield. The alloy sub-frame reinforcing plate stays in place. It took two long extensions and two universal joints, making a tool over 1m long!! Dr Suess, I believe Andrew would say...
This was inserted from behind the transfer case, over the top of it, alongside the transmission and then (via the universals) up onto the starter bolts at the top edge of the bell-housing. Fun...
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The "rebuild" of the starter was very straight forward, with no parts needed, just a damn good clean and re-grease. Couldn't exactly diagnose what caused the high current draw and slow operation - possibly a combination of old, dried grease mixed with a small amount of carbon dust from the (barely even worn) brushes and said carbon dust shorting the segments of the commutator. Anywho, once it was all cleaned down (using the only spend on this job - a $12 can of CRC non-flamable parts cleaner), greased correctly and re-assembled, bench testing showed it to perform well, so back into the car it went.
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Moment of truth, holding my breath.... Wow!! This thing now spins up so fast and the engine is running almost instantly! Very pleased... esp. since the OE Bosch starter could probably last a million kms if serviced occasionally, it's so darn well made. Can't actually say if it's better than the aftermarket options but I'm betting it is...