transmission polishing??

[roj2323]

hey guys,
i know there are a few of you crazy's who have polished your transmissions instead of painting them so i was wondering if you might share your story and give me some pointers as to how i might want to aproch this time consuming task. i'm working with a 700r4 so there are a few tight areas as well as alot of surface area so any pointers would be awsome.

thanks,
ondrew

[dwcsr]

Polishing castings is a lot of work.

Grind off the parting lines and unneeded ears and tabs. Don't grind to the case with too coarse a grit and don't grind the part lines down to the case with a grinder disc. You can use it to knock off the big stuff but not down to the case. Once that’s done you need to start with something like 50 then go to 80 then 100 then 120 and so on up to 320 or 400. Your trying to remove the high spots without leaving scratches from the previous girt. you may go back and forth on a grit till you get the marks out but the trick is to not grind to heavily and not leave deep scratches that need extra work. Use open coat sanding disks they won't load up as much.

If you are going to truly polish it then start with the buffing. Use a fast cut compound like Brown Tripoli. You could try a green bar then for final polish or White bar, you'll have to experiment. Red should only be used on a polish that needs to be like chrome and it will cake up on the aluminum and the polishing wheel and most likely leave a ghosting or dulling effect at that spot. If that happens, try and aluminum oxide powder mixed with water to form a paste.

One point on buffing is that you never use the buffing compounds on a polishing wheel. It will wreck all that hard work.

Buffing is the process of taking out the minor scratches and imperfections in the metal, it is not for a shine and it will not take out big scratches that you can feel with your finger nail. Never use different buffing compounds on the same wheel.

Polishing is for the shine and never use a different compounds on the same polishing wheel.

Each grade of compound gets its own wheel.
Always wear a mask your chest will kill you if you don't.
You will be dirtier than you ever though you could be after you’re done.
Don't use these grinding wheels for grinding welding joints once they have ground aluminum.
If you wear glasses rinse them off before you clean or wipe them or you will scratch the heck out of them from the compounds.

Good luck.

[Kevin45]

To polish something like a tranny would be a ton of work, not counting that after it is polished, you will have to stay after it or it will dull back up. Aluminum will stay shiny after it is polished if it is clear anodized afterwards. to coat it with a clear paint you need to have something for the paint to bite into, hence sanding it, therefore undoing what you did. Best bet would be to prep it like body work and either paint and clearcoat it or there are a multitude of powdercoatings available and go that route. I work with aluminum everyday (machinist and tool & die maker) and I see what it takes to shine a piece of aluminum. Also some grades of aluminum you can get a mirror shine out of it and other grades you can only get a mediocre shine. With a tranny being cast aluminum, you will not get the chrome look that I think you are looking for. It will end up more of a duller billet looking shine and a darker shade than actual billet type of aluminum. For comparison I will say a tranny will look like the older slotted aluminum wheels from back in the '60's / '70's era when polished compared with what you would expect to what a set of March pulleys and brackets would look like with a mirror finish. Sorry to go on and I realize that this post is a few months old, but I hate to see someone waste their time and end up with less than expected results.

Kevin

[Alex Hayley]

Does anyone happen to have a picture of a polished transmission?

[Musclerodz]

Not polishing mine, but I took a 3" 60 grit roloc wheel to all the casting flashing and any slag I could feel when I ran my hand across it. Couple coats of high build primer and 2 part urethane, it will look nice and smooth.

Mike

[mbgmike]

We use a wheel made by Norton and others. It can be used for stainless also. It looks like a grey stone wheel but not. We use them alot on harley Jugs to polish fins. We don't use polishing wheels much, takes too much time.

[Orange]

Originally Posted by Alex Hayley

Does anyone happen to have a picture of a polished transmission?

This one USED to be. This is after quite a few thousand miles though. Doesn't look so polished now. I sanded, and polished, and ground for DAYS on this think. There isn't hardly a burr on it anywhere. If there is, it is a smooth burr.





If you were to go back over it and clean it up again, you can visualize what it would look like. Just a dark polished piece of metal.

DLB

[LONGHAIR]

Kevin45 is absolutely right. Much of the final outcome has to do with the quality of the aluminum. The harder alloys not only take polishing better but they hold it better too.

[N2TRUX]

Smooth it, paint it and be done. Since you can barely see the transmission once installed, it is not worth the hassle to polish. Besides, as mentioned the quality of the casting is porous so it will not maintain a decent shine.

Here's mine after paint....

[Alex Hayley]

N2TRUX, what paint did you use?

[resin addict]

How about powder coating?

[gregfull]

I'm with you N2, did the same on mine.