QuestionI have an '89 Cadillac Deville(ATM, 4.5L V8) that just recently(about three weeks ago) had the following problem develop. Whenever I push the gas pedal down to the floor, the transmission seems to downshift one gear too far.
For example, I tried just flooring it for a little bit when this problem first started arising, and the car refused to shift out of 1st gear until I let off of the pedal.
The same thing happens when the car is moving and I try and floor it to get the car to move into passing gear. I'll be going 45 mph, and I'll floor it to give the car that extra "oomph" to get up to highway speed, and the car, instead of shifting into passing gear, will automatically shift to 1st gear, causing it to redline horrendously and jerk as a result of the sudden compression.
The problem seems to go away once the car gets above 65mph, but it seems to be stuck in overdrive, so acceleration is terrible. I live in MT where the highway speed limit is 75mph, and I have a lot of trouble getting up to that speed, even with the V8.
I just gave it a transmission fluid flush on April 21st. The mechanic said that he couldn't find any metal shavings in the fluid, but he did say that the fluid was pretty old and black.
Any help that you could give me in trying to figure out what the heck is going on with my Caddy would be greatly appreciated.
Thank you so much in advance,
Davis Diede
AnswerHi,Davis
Though it could be a few things that cause this,the easiest and most overlooked fix is the TV{throttle valve}cable,now this could save you a trip to the trans guys and money,i know they will be cursing me up and down,but locate the cable at the throttle body,there will be 2 cables one is for the pedal the other is the TV cable,its is located on the same bracket next to the throttlebody and has what looks like a large metal silver button,leave the engine off,depress the button inward then move the front portion of the cable inward,release the button,then engine still off,move the throttle slowly all the way to wide open throttle,you will feel resistance while doing this and you will hear the cable ratchet outward,this is normal,do this to wide open throttle then release,road test and see if shifting is normal,the TV cable is what sets up shift points and also passing gear{downshifts},you can adjusted the shift points a little bit more by adjusting the TV cable outward 1 click at a time,to much and the shift points will be very high and you wont have passing gear.let me know if you need more help.
ED
