Disengage during downhill deceleration

[Hawkeye78]

So I recently had a chance to put a couple thousand miles on my '07 SE while taking a road trip across the Midwest and I experienced a couple of things that have me scratching my head:

1. I notice that during large hill descents at highway speed, I feel what I can only describe as a light disengage shudder when I let off the gas. It happens repeatedly if I have the cruise control set - it's as though it is constantly (but slowly) engaging and disengaging power while descending the hill.

2. There were two separate instances (different days) where I was on a flat road at highway speed with the cruise control set and I felt something "slip" - it was as if I was accelerating and hit a small patch of ice on the road. I have driven it 1k miles since then in the same conditions and have not felt anything like it. The roads were clear and dry when this happened.

My SE has 64k miles. I had performed the bypass at 62k when I bought it, at which time the transmission fluid looked blood red. In fact, the transmission fluid has probably been changed twice since then due to leaking transmission pan gasket (the dealership somehow managed to screw up this simple job). Having just bought it with 62k miles on it, I can't verify that coolant hasn't contaminated the transmission prior to me owning it, but this doesn't seem to follow the same failure modes that I have read in other posts.

Does anyone have thoughts on what the issue might be?

[NVSteve]

1. It happens repeatedly if I have the cruise control set - it's as though it is constantly (but slowly) engaging and disengaging power while descending the hill.

I have experience with this one. Totally normal symptoms for the cruise control, which really is not suited for going up or down long, steep grades. You are far better off turning it off and manually shifting when needed.