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Not shifting into overdrive


bookie400

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Hopefully someone can point me in the right direction. I have a 94' Cutlass Supreme 3.4. Sometimes after driving through town for a while my car will not shift into over dirve when I get on the highway. I then have to pull over and shut my car off for a few minites. Once I take off again it will shift into over drive. It does not do it all the time but it is getting realy anoying. Any ideas on where I should start looking?

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change the fluid and filter, usually, thats the best place to start. It will clear up problems you didnt think it would, and never knew you had.

 

Robby

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It might, cuz if theres too much vacuum, the shift will be really slow and sloppy, it may not shift at all, I dont know. Hey, JS91Z34, how would the MAF being bad, cause it not to shift? Just curious, Im not up on my MAFs and how they work

 

Robby

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If the MAF sensor is bad or faulty it will not be able to determine how much air is being drawn in by the motor. Therefore not being able to tell how much of a load is on it, and not tell the car to shift in accordance to throttle position. The MAF sensor controls alot of key features other than telling the computer how much air is drawn in. :) :)

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If the MAF sensor is bad or faulty it will not be able to determine how much air is being drawn in by the motor. Therefore not being able to tell how much of a load is on it, and not tell the car to shift in accordance to throttle position. The MAF sensor controls alot of key features other than telling the computer how much air is drawn in. :) :)

 

Makes perfect sense, thanks!

 

Robby

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  • 4 months later...

Any time the temp guage reads 195-215 deg. At some point in the next 10 -15 mins she jumps out of overdrive. I do not mean the tourqe lock up, I mean I pull the shifter down to 3rd and rpms do not change save in the OD position, when I let off the throttle the rpms drop to almost idle. I am about to change the fluid and filter which I have terribly neglected. If anyone else has had a similiar problem please shoot me an e-mail. As of now I am not getting any trouble codes. Thanks all

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Changed filter and fluid. To my disapointment the problem is still there. She shifts smoother now though. I purposely let her heat up to 200+ by sitting on the side of the road with her in drive. Shortly thereafter while on the highway at a speed of 65-70 she jumped out of overdrive. At the time the engine temp had cooled to 160-170ish. When I let off of the accelerator the rpms drop to approx 1200. When I give her gas she acts like she's out of gear until she gets to around 3000rpm. Like I said on the previous post, she's not kicking any codes. I may be ignorant of the system but I would think if the MAF was flakey it would cause a code to be kicked. Unless underhood temp was effecting it. Any help is appreciated. Thanks.

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Changed filter and fluid. To my disapointment the problem is still there. She shifts smoother now though. I purposely let her heat up to 200+ by sitting on the side of the road with her in drive. Shortly thereafter while on the highway at a speed of 65-70 she jumped out of overdrive. At the time the engine temp had cooled to 160-170ish. When I let off of the accelerator the rpms drop to approx 1200. When I give her gas she acts like she's out of gear until she gets to around 3000rpm. Like I said on the previous post, she's not kicking any codes. I may be ignorant of the system but I would think if the MAF was flakey it would cause a code to be kicked. Unless underhood temp was effecting it. Any help is appreciated. Thanks.

 

What year/motor/trans do you have?

 

Robby

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sounds like fluid viscosidy (sp?) to me. the fluid is to hot to press the valve against the pin to tighten the band for the od

 

i have seen on my car the fluid got real thin when it was hot but i didn't have a problem with it not shifting into od

 

i could be wrong!

 

but i hope this helps

 

P.S. check the fluid when it is warmer than 170 and see if it is thin and that may or may not tell you a little

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Robby, she is a 95 Cutlass Supreme with a 3.4liter engineer's wet dream gone awry and a 4T60E tranny.

 

Today I am planning on checking to make sure the cooler is not clogged. I had read something about there being a transmission fluid temperature sensor and that the ECM reacted to the temperature in some way. Exactly how I have yet to discover. She shifts through all the other gears with no problem even after jumping out of overdrive.

 

Thanks for all the posts. I appreciate it!

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