Quote:
|
Originally Posted by cl1986 Hmm, that is really funny, my 91 deville with 4.9L did same exact thing starting at around 170,000 miles. The thing is, mine was trying to shift into 1st gear while in park or neutral. I sold the car with 189,000, during the summer it wouldnt do it. Winter is the problem. I am 95% positive that it is a valve not closing and causing it to try to go into first. One time the car even moved ahead a little because of it.
To get the most out of the tranny, start the car and immediatly put in Drive. You could set the parking break first, but this is a problem because the car automatically releases the brake when started. Maybe you can change the parking break back to old style somehow.
Main thing is, your tranny is going to go. When?? Not sure. We drove ours for over a year like that. |
I'll bet it was the sprag. When it grabs like that the inertia of the spinning elements inside the trans does tend to rock the car forward...but it is the sprag clutch causing that.
Good advice, though, to start the engine and immediately shift into gear so that the sprag will not have to overrun while the engine fast idles in neutral. The shift into drive or reverse will be far less traumatic to the trans than the sprag grabbing.