What happens in a transmission rebuild - Part 2

[Mac VP]

LINK TO ORIGINAL POST:
https://www.fordbarn.com/forum/showthread.php?t=278347

So with each succeeding development of the 49 Merc overdrive trans rebuild, we will set it up as a fresh thread so that the comments and questions don't extend the thread page too much. This next thread will carry practically the same thread name but will be Part 2 (eventually followed by Parts 3, 4 and so on). I am not concerned with keeping to a tight schedule on bringing each fresh thread to the site, so you will have to watch for them. Thanks for the kind remarks!

Part 2 simply shows the process of cleaning the castings. They are placed in a sturdy basket and taken to a partner shop who has the industrial oven system for cleaning engine blocks and such. The castings are placed in the oven and baked at about 500 degrees for about 45 to 60 minutes depending on how many items are in the oven and how nasty they are. The gas fired oven virtually burns off any old paint, oil or grease.

When the oven cools, the parts are removed and placed in the rotisserie media blast machine. They are tied into place with wire. The machine turns the parts while the media (ie shot blast) is thrown about inside the cabinet. This process removes any residue of burnt ash, and of course, any rust that might be on the castings. There are two impellers that take the media from the reservoir and, spinning rapidly, throw the media at the revolving cage.

After this blaster unit is finished, the parts are blown off with compressed air, and then placed in a wash cabinet. Any dust or debris is rinsed off. The castings are dried. At this point, we have them painted with the usual "cast blast" gray paint at our request. We don't want the castings to turn brown which they would do fairly quickly if we didn't protect them.

When they are finished up we pick the castings up and return them to the transmission shop for the next steps.

Here is the link to Part 3:
https://www.fordbarn.com/forum/showt...28#post1866528

[Lawrie]

Mac ,you are fortunate to have access to such a cleaner, any engines or trans that I do in my shop are cleaned manually with wire brushes and kerosene etc ,a real messy job.
Lawrie

[cas3]

i have access to a shot blast cabinet like that, it shoots cast iron balls. i have used it on cases, but you run the gears and shafts thru there too?

[Mac VP]

The bake and blast process is only for the exterior castings. Way back when I first began to rebuild transmissions on my own, I scraped and wire brushed them before scrubbing with soapy hot water. What a long messy job that was! Plus you never really got it all that clean, and it didn’t do much about the rusted castings.

The wonderful thing about this process (for us as a shop) is the significant saving of time. We get totally clean castings..... and I do mean totally! You know how it is with the little nooks and crannies. You could never get them properly cleaned by hand scrubbing. A great side benefit is that our sealing compounds stick very well to the clean surfaces.

As for the gears and shafts, we utilize a completely different procedure for them....that’s coming up in one of the next threads.

[Mart]

Great stuff, Mac.

[Seth Swoboda]

Sponsored Links (Register now to hide all advertisements)

I'm enjoying these segments. Thanks Mac.

[RKS.PA]

Mac, this is like your book on steroids!!!

Thanks for taking the time to do this for us!!

Dick.

[kegmon]

This is the best thing on the internet right now...

[Tim Ayers]

Thank you for a peek behind the curtain!

[Ol' Ron]

when I ran my shop, I sent all myBlocks ans etc out for bake cleaning. At the time it cost 65 per block, worth every sent!
Gramos