The upper case on my drive is turning a purplish tint. Its a alpha drive with a shower on top. It shouldn't be getting hot with the shower and after running it, it never seems hot to the touch. Is this caused by heat or something else? I flushed the fluid and put new in, it didn't look any different then it has before. What would cause this. It works perfect and no noises from it.

Probably just oxidation. I dont have a drive shower, and get calcium crust on mine from getting hot. I WILL be getting drive showers for next year, but for now, it is what it is...

It only seems to be on the top of the outdrive. Nothing around the lower case.

Mine does that too. Someone told me awhile back that exhaust fumes will do that. Not sure if that is it but I guess it makes sense.

Only the part that is exposed while running on plane has the tint to it.

Long ago I had an old Ford truck with the exhaust exiting in front of the rear tires. I put new aluminum rims all the way around right before a trip to FL. When I got there I noticed rear rims had an ugly tint to them when you looked at them at a certain angle. Me and my buddy thought it was the exhaust with 12+ hours at highway speeds.

hmmm ok.

I have seen the upper turn purple before inwhich was very noticable. keep in mind this section runs out of the water after getting the hull on full plane.

What i have found was on a couple of these the water jackets in the exhaust riser & manifold were very restricted with scale, rust & debrie causing a restriction of water flow.

The exhaust system and all the portion of the exhaust going thru the upper end of the drive was getting to hot causing the discoloring. Also ur upper maybe running too hot maybe a upper bearing problem or the gear lube running too hot or breaking down. Might need to be change & use a quality brand.

Boat has thru halls. No exhaust exits the drive.

Leaded fuel does it big time