I’m getting close to finishing my transmission, it just occurred to me that what is gray coating on my old pump slide. I know I mentioned my old parts in other related threads. Also here are some pics of my old vanes, I’m having a gut feeling that I should use the old pump parts. There is guy named Hiram Gutierrez on YouTube that mentioned the gray coating on the pump surface.

 

I watched Hiram's disassembly video for the 4L60E back in 2014 because I couldn't get the band anchor pin and band out of the case.

What is the nature of the gray coating? Is it a factory applied coating or some kind of burnishing or wear that happens from being in operation?

 

I guess the gray coating is a sign that the part has very little wear. How come does my new slide does not have it. I know everyone is hi performance driven on this forum, I just want my transmission back to like it was before, I wish I could find an NOS ac delco pump

 

Here is another pic of the slide where vanes don’t ride. I’m not an expert on metallurgy but I guess it might some kind of salt bath nitriding or parkerized finish. I don’t see this kind of finish on any other pump repair kits that are aftermarket.
I might stir up some flack among the aftermarket transmission parts suppliers out there but I think gm had some revolutionary stuff on some of their cars back then. Granted they had some horrible things. But I remember as kid back in the late 80’s and early 90’s gm was one of the best for transmission reliability and electrical systems, most of all they were all dirt cheap to buy. Toyota’s and Honda’s and even European cars were still kind of shitty. I myself drive old Volvo’s for my winter rats. The only reason I don’t drive gm’s or anything American these days is because they rust to hell. Anyway sorry for my rant I got 200k miles and 15 summers out of my transmission and I drive my cars daily. I just think aftermarket parts for American cars these days fall short when it comes to being an exact replacement.

 

Oh I forgot to mention the new slide has an almost mirror finish in the area where the vanes ride. In addition to this I mentioned in other related threads there are subtle differences in terms of dimensions. Can anyone who is fluid dynamic engineering field possibly chime in. No offense to the other guys out there I’m sure they know their stuff as well. Maybe any SAE guys out there???

 

I went back and FF'ed through Hiram's 4L60E Transmission Teardown Inspection - Transmission Repair video where he mentions the gray color of the pump slide around the 35-minute mark.


He eludes to the gray surface color being there when the parts are new and gets worn off as the mileage accumulates. His conclusion was it wasn't new, but wasn't worn out either.

I think the gray isn't so much a coating but a result of the manufacturing process of the parts. Your replacement parts probably didn't go through the same manufacturing process as the ones being replaced. There isn't any data to support this, but I don't think you can say that the new, shiny parts aren't as good or better than the originals.

 

Going back to when I mentioned the pump spins very smooth by hand. I’m trying to visualize what could possibly go wrong

1) Maybe the pump pocket is not 100% smooth and the slide will not seal perfectly against the ring and cause a pressure drop. I couldn’t feel any scoring just a slight waviness. The thing is under high pressure during operation in a small occupied chamber and the aluminum normally fatigues.

2) When the unit is pressurized during operation the vanes could move closer to aluminum and tear the **** out of the aluminum and send my all work down the drain. The rotor to vane clearance is double the amount versus my old parts, less than 0.001 vs 0.003, does this make a difference in terms of generating proper hydraulic pressure.

3) My transmission shifted flawless, and I mean flawless before all this happened. There were no warning signs just out of nowhere the car felt like it was in neutral

 

Oh also I was told by the torque converter supplier guy, when I swapped my old one as a core he found water inside it I guess that what caused the clutches to explode

 

Begs the question, where did the water come from?

I'd make sure to flush the cooler lines and check/replace the radiator before installing the finished transmission. Coolant is a death sentence.

 

I mentioned in a previous post some months ago about what I think may have caused the transmission. The problems happened 2 days later after I had to drive thru some flooding on Halloween night to get home. I described in detail the chain of events that happened.