Breaking free old frozen transmissions: Tricks?

[RalphM]

I just had a stuck transmission given to me. Open drive, 40’s ish, I haven’t uncovered the serial number yet.
I had a gallon and a half of evaporust laying around, used, so thought I’d experiment. Instructions say 30 min for light rust, overnight for more. I’m going to let it sit for a few days before I check it.

 

[fordor41]

for small stuff, nuts and bolts etc I've used muriatic acid. can get it at any home center. just don't soak things too long.

 

[F-ONE]

for small stuff, nuts and bolts etc I've used muriatic acid. can get it at any home center. just don't soak things too long.

Anything I have personally used muriatic acid on was eventually destroyed. I was careful. I cleaned and neutralized. The stuff looked like a million dollars.....

Until it crumbled to pieces.

I found a possible reason for this. The stuff is hot! Another thing is it can produce chlorine gas.

It seems muriatic chlorinates the steel. In other words it impregnates chlorine into the good steel at a microscopic level. Chlorine is an oxidizer.

Paint or even grease may prolong something treated with it because it seals out oxygen. Eventually though....it will rust.
Any untreated surface may look great but will turn to poo poo rather quickly.

 

[tubman]

I just had a stuck transmission given to me. Open drive, 40’s ish, I haven’t uncovered the serial number yet.
I had a gallon and a half of evaporust laying around, used, so thought I’d experiment. Instructions say 30 min for light rust, overnight for more. I’m going to let it sit for a few days before I check it.

I have used Evaporust quite often and like it a lot. I have never used it for something like this, though, and will be quite interested in how this turns out. From my experience, it will probably take several sessions, because the stuff does "wear out".

I will emphasize again that this stuff is not an acid, and therefore doesn't deteriorate he metal in any way. Acid will eat rust, but unfortunately adversely effects metal. It's just a matter of degree.

 

[RalphM]

I almost forgot about the transmission, it’s been a week. I just drained it out started to clean it but it’s still pretty stuck so back in the solution it goes. I have hopes of getting this one free because the gears and syncro’s look pretty nice.

 

[JSeery]

I almost forgot about the transmission, it’s been a week. I just drained it out started to clean it but it’s still pretty stuck so back in the solution it goes. I have hopes of getting this one free because the gears and syncro’s look pretty nice.

I think a clean new solution would make a world of difference over reusing it.

 

[RalphM]

Your probably correct, I did add about 1/2 gallon of new evaporust to it today. It’s just the stuff is expensive, at least here. I think I paid about $40 for two gallons. I see Home Depot here has a 5 gal bucket for $76.

 

[tubman]

For stuff like this, I use something called "Rust-911". It's a concentrate, so it's a lot cheaper than Evaporust. In the long run, however, I don't think it does quite as good a job as Evaporust, but for something like this, the savings are worth it.

Here's a link : https://www.rust911.com/rust911-ultra-concentrate-rust-remover-dissolver-treatment-free-shipping/.

It looks like you are getting pretty good results with that transmission.

 

[Mart]

I'm going to be blunt here. I think you may be wasting your time. De-rusting something like a gearbox casing or old crescent wrench may be worthwhile but when it comes to precision engineered parts like gears and synchros you must surely be left with pits where the rust has eaten in.
Not trying to be a killjoy, but realistic about the potential outcome.
I hope you prove my conjecture wrong and have a good usable set of gears, but I don't believe that outcome is guaranteed.
Mart.

 

[Bored&Stroked]

In looking at the last transmission pictures, it does not appear that those gears will be usable - you can see heavy rust pitting on everything. I'm with Mart - rust pitting on precision machined parts - will ruin most of them.

 

[cas3]

and, while i am no engineer, i have always been told that the case hardening on the gear is not too deep, so it goes away with the layer of rust leaving you with a soft pitted gear. fact or fiction...take your pick

 

[tubman]

I know you guys are right, but I would like to see him complete the process just to see how well it works. The gears are probably toast, but the synchronizers look pretty good. I would like to see this taken to the point where we see if he can get that transmission to the point where he can disassemble it.

 

[rotorwrench]

I won't tell anyone not to do something but I will say that every rust pit is a potential stress riser for cracks. Cracks can lead to tooth separation.

The old ford transmission cases are sensitive around the front bore that the countershaft fits into. Any rust pits in that area won't make it stronger. The thrust surface on the back has to be smooth and thick enough to act as a thrust surface in conjunction with the thrust washer that goes in there.

 

[tubman]

To me, it's more about the Evaporust than the transmission.

 

[cas3]

evapo rust is a good thing, no question about that. i just hate paying for it! agree 911 is good too, but sightly weaker/slower. its all just another "if ya wanna dance, you gotta pay the fiddler"

 

[JSeery]

To me, it's more about the Evaporust than the transmission.

I agree, was interested in seeing the results! I have been using 911 because of the cost difference.

 

[RalphM]

Kilroy,
Any luck with your transmission?

I’ve only been at the evaporust for two weeks, started with a used batch. But I’m impressed at how clean it is getting after two weeks. Still not free to move, but I think I’ll invest in some brand new if Evaporust and see how much further I can clean it. I lightly wire brushed the part of the gears I could get to and there is not any deep pitting in them.
So I’m still hoping that some of this might be salvageable.
Ralph
My really good pictures won’t load this is the best I can do

 

[JSeery]

Looking better! If you want any additional photos posted you can email them to me: jseery@ymail.com

 

[JSeery]

Two additional photos Ralph wanted posted.

 

[Zeke3]

Impressive progress.