I've got a 1970 442 with a 455 and TH400. For years I've had a slight stutter/slip when shifting from 2nd gear to 3rd gear if running full throttle (no big deal because it's not often that I'm full throttle going into 3rd).

In any case, I just changed the radiator over the weekend. Now the first time on the throttle somewhat heavy after the radiator was installed, it didn't want to shift into 3rd unless I let off the gas. Then it seemed to slip more than normal in 3rd. ...but under normal light driving you would never notice it.

So the question is, could this be something related to the transmission cooler in the new radiator? Or is it just a coincidence that this problem is showing up at the same time? When I hooked up the tranny cooling lines I did have a small leak at first, which could have introduced some air, but I would think the air should have worked itself out by now.

Any thoughts or input on how to fix this or what could be causing this are appreciated.

Keith

 

Simple question, but did you check the fluid?

 

Did you check the modulator line to make sure you didn't somehow unhook it?

 

The modulator line is still hooked up, and the fluid is at the appropriate level.

 

Is it at the appropriate level with the engine warmed, running, and in park? Is the color ok and doesn't smell burnt?

 

Correct. The fluid is clean, doesn't smell burnt, and was checked idling in park warmed up after a short drive.