I recently had the fan housing cerakoted and now I want to do the transmission. On the fan housing I removed all the grease and oil and the shop that applied the cerakote blasted it withe 200 grit aluminium oxide in a cabinet and it came out great.

I will get all the grease and oil off the transmission, but the blasting will be done with 100 grit aluminum oxide outside of a cabinet. I believe I have protected everything but was a little concerned about 100 grit being to course.

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I would only soda blast unless you intend to overhaul the trans after blasting.

I cleaned mine up getting rid of all the oily mess before one of the Doc’s trany clinic’s then painted the outside as it needs a protection coating anyway.

Because of getting into bearings on the drivers? I packed them with foam and wrapped tight with duck tape. I don't intend to overhaul trans. Thanks for help

I've only used crushed walnut shells for whole gearboxes. I'd be concerned about a real hard/aggressive media getting inside.

The heavy duy foil backed duct tape really helps protect unwanted areas for media blasting.

Thanks for response I am concerned. I have packed hard around the bearings to the drivers. I don't know what to call the area. If I can get the area 2 to 3 inches away from bearings and tape this off would that relieve the biggest concern

Dry ice would be another way to go but I wouldn’t do an abrasive material.

I wouldn't use sand. . I doubt that any tape or sealing will keep all
of the abrasive out. . I'd go with plastic beads if you can't do the soda or dry ice, which
would be my first choice for an assembled tranny. .
However, all of this is a substitute for doing it right. . pull the trans apart, blast it, then put in in a vibrator ceramic tumbler, and you'd have a perfect original finish . . .

This is bare Mag, no paint. . it was then coated with an Aerosapce metal protectant from Boeing called Boshield,T-9. It is similar to WD40, but dries to a waxy protectant finish that penetrates the pores of the mag. . I did mine 8 years ago and it looks the same today.

I agree with all of the above comments
to the OP

you will not keep 100% of the media out
that media will in turn ruin your bearings
and then you will be spending 2k on the rebuild in 2 years


please if your going to blast... use dry ice or soda. something that will dissolve and definitely not a silica media. That is the wrong way of doing this job

Great input. Stay away from sand. I have no experience with plastic beads but sounds promising. Walnut shells is messy but works terrific. If and when I redo a trans, I'm trying Boshield T-9, if I can find it.

I used a 30-60 Garnet yesterday to blast some doors for a fellow SoCal member @Steve


Oscar

This is the best response, but others hit the nail on the head with recommending not blasting it.

I have never had one blasted the didnt have some intrusion into the box. You are forcing small hard particles at the box very fast. They will find a way. And you only need one particle to get in to wreck a bearing, and then, and then....

Its not much effort to pull the thing apart, clean, blast, change all the gaskets, put back together. Just match the gasket between the intermediate plate and case.

When I had a friend with a washer, that was the best first step if you cant do all the exotic treatments mentioned here. The ones lke a giant dishwasher with jets and hot water based soap solution was great. Likely you can find a shop near by with one that will let you wash your stuff for cheap or free. Takes like 20min and comes out clean, but somewhat stained metal. Then, I have used Hammerite from Krylon to paint for easy effect.

Thanks for all the responses. I have spent about 10 hours cleaning on the d thing. I am going to clean a little more and just live with tran envy until I have time and comfortable doing it right. The world saved me a big problem. Thanks again

We do quite a few gear boxes at Rothsport. 1 to 2 trips thru the hot water jet washer. The real grimy ones get a good soaking of Gunk engine cleaner and rinsed prior to the jet washer. Never blasted before dis-assembly. After tear down they head to the soda blaster for outside touch ups and detailing the innards.