Technical Would you run it? Magnuflux looks bad...

Transmission is a Mopar 3 speed, with BW R10g-1 overdrive unit.
I have been wondering about cryogenic treatment or micro shot peening, even before finding this. I was originally planning on having it done, then sending everything for Isotropic polishing.

did as you said


Also checked my NOS Sterling brand Input shaft, I dont like it either.

These lines I can see and almost feel with the naked Eye, I wonder if they were scratches that got finished over? Or worse, flaws in the base steel.... at least I have the option to not run this.

I couldn't find the dye pen stuff yesterday, I will get my NDT guy to dig it out and we will check both of them with dye tomorrow at lunch.

 

Good luck with the test, I hope it turns out OK

 

Think of those cracks as being very shallow depth, as I recommended if you dye penetrant test, the dye may not have much crack to seep into and you may not see much result. Indicating they are very shallow. While any cracks are not good, think about flywheels where they get the cracks. Of course those can be machined off; while your trans shaft can;'t be reduced diam. But those flywheel cracks do not really cause any issues for normal driving.

 

Might put some want ads out on some of the Mopar forums. Moparts.com, forabodiesonly.com, forbbodiesonly.com, forcbodiesonly.com. Some of those guys and gals may have a trans for parts they want to get rid of. Finding a spare trans or input shaft to use as a backup if you decide to run what you have as is.

 

I suspect you are not going to find any nearly 80 years old machined part that is going to pass this inspection.

Look at the part, and consider how it functions in its operating position with everything present. Then, tell me in which direction any cracks that are going to cause a failure are going to appear on the part.

If the cracks you are showing on the last part would fail because of those cracks, the end you are holding would break off with side to side movement. Is that even possible with that part in position with all the other parts around it? Had the cracks been located from the base of the keyway or at the bottom edges of the teeth cuts in such a way it might show the shaft splitting side to side along the length of the keyway or along the length of the tooth that could cause them to breaking off, I might be concerned. In other words, a crack running the length of the shaft, or 1/2 way around and then extending to the end of the shaft would be concerning. The crack going all the way around the shaft would only be a concern if the end of the shaft could move side to side enough to break off.

The parts you are concerned about are in a low force, low pressure position, with a low power application. The very minor cracks you are seeing are in an area on a part that very likely can not break in the direction the cracks could cause.

That said, cracks like those on either end or at any journal on a crankshaft in a motor is a different matter. Whenever you check for cracks on machined parts, you need to take into consideration the depth of the cracks, and if the cracks you are seeing can really cause a breakage on the part you are inspecting when it is operation.

 

Micro cracks can develop when surface grinding, if the metal gets too hot.
Very shallow.

 

What could go wrong, car still has an original floor pan, right?