shudder like problem

[Jackpine]

Originally Posted by not you

How do i do this, hex code and serial number . The cruise was not on and it was a flat road it doesnt do it all the time once with me with the wife driving and a few times with just the wife. Its not a tire issue because it would do it all the time correct?

Generally, that is correct - a suspension/tire problem should show up at all times at a certain speed. But, I found in my truck there were times when it was far more noticeable than at other times. I feel it was a property of the road I was driving on.

The "shudder" description is still bothering me. I interpret that word as describing a very rapid vibration - kind of like a "shiver" when you are very cold. Somehow, I can't visualize how anything in the transmission could cause this kind of rapid oscillation - but an unbalanced tire sure could. It would be a kind of "shaking" sensation that you'd feel in your seat, and if it were from the front end, you'd probably feel it in the steering wheel. As I said, it took about three tries to get my wheels balanced, and I had not thrown any weights - things just seemed to "change" as the new tires "broke in".

I'd expect something funny in the transmission to be a slower effect, and it would have kind of a forward/backward motion. I'd also be surprised to see it happening at 70 mph, unless the truck is under a slight load, perhaps climbing a hill.

I wonder if this could be a somewhat aggressive closed-loop fueling problem? The system there is constantly alternating between too rich and too lean to average things out at the proper stoich, and maybe it's "overshooting"? Just a thought, any experts want to give an opinion on this?

- Jack