Hey guys,

I have a '69 442 with a built 455 and a Th 400. I had the trans rebuilt using a TCI kit. It's been a while so I don't remember the exact kit but it had the clutches, steels, HD sprag, ect ect. This has been about 8 years ago. Soon after I had the trans rebuilt the car was parked and not driven. I remember when I was driving it kept wanting to upshift then downshift from 2nd to 3rd. All the while I was going at a constant speed of about 35-45 mph. I was told that it may be my modulator or governer. I have manifold vacuum. What could be causing this? Any help is appreciated. Thanks!

Dan

 

It possibly could be a leaking rubber modulator line, modulator and/or governor. It could also be associated to your kick down switch. It may be internal to the trans.

 

The trans shifted fine before the rebuild so it would lead me to believe that it is something internal or a vacuum leak. I will try replacing the modulator and see what happens. Thanks.

Dan