Maybe three or four times i go out driving, my car will shift into overdrive at 35-40 mph. It is annoying, because i really slow down. It only happens if i'm only giving it a little gas, just cruising. I was wondering if it was the tranny fluid or filter. I have both sitting in my garage but it's getting so hot out . Could this be affecting it? It shifts fine at 1/4 or more throttle. Thanks.

~Matt

 

Mine does the same thing. From what I've been told you change a governor to make it shift a little later, which is a part in the transmission. I burned my PROM to make the torque convertor lockup happen later, so my engine doesn't bog as much... but it's sorta annoying to have OD kick in at 38 mph with 10% throttle.

 

Yeah, it is annoying. Did you change your governor? I know some people here have swapped Corvette ones and i bet that helps. Thanks.

~Matt

 

Exchange one governor spring for a slightly weaker one. Lightening the weights will help also even at part throotle but will raise the wide open throttle shift points.

 

Sounds to me like he's talking about his TCC locking up, not jst going into overdrive. And sounds like normal TCC operation to boot. If you really have a problem with it the only way to change the TCC lock-up paramters in the chip.

 

Under normal "light" driving conditions in OD it will shift into 4th gear at 35/40 MPH its normal. If its shifting into overdrive with a good amount of throttle at 35/40 then you need to readjust the TV cable. Light TV pressure will cause early shifts.

 

No, it only shifts early at small amounts of throttle. Thanks.

~Matt

 

What you are experiencing is normal for the f-body. Same for V6 or V8 engines. If you would like this to not happen and get better fuel milage at the same time , just leave the shifter in D instead of OD . If you get out on the highway, bump it into OD after 50 mph.