How to know if overdrive actually works?

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  #1  
Old 07-27-15, 12:00 PM
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How to know if overdrive actually works?

Something's not right with our 99 RX300 transmission. For starters, when cold, it will shift from 1st into 2nd only about quarter mile down the road. Thereafter will be shifting just fine all day long. ATF chnage helps for some time then it goes back to same issue.
Next, when rolling at speeds above 35 or so, it feels like as if transmission is NOT in overdrive. Like something holds it back.
Pressing OD button on gear shifter produces downshift and car slows down. So it passes that test. RPMs appear to be proper for OD on tach.
Brakes and all that that can possibly cause drag are fine.
She simply does not roll right. Has 156 000 miles and been stellar car so far.
Is there any other way to find out if OD actually engages or not? I had Sable took me 2 years of ownership to realize that it has no OD functioning.
Maybe I'm simply looking for black cat in the dark room that is not there?
 
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  #2  
Old 07-27-15, 12:06 PM
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To me the fact that it downshifts when the overdrive is disengaged means that it was in overdrive.
 
  #3  
Old 07-27-15, 12:17 PM
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Have you checked codes just to see if there's anything in there which didn't trigger a warning light?
 
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Old 07-27-15, 04:26 PM
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Several times. I have good scanner that actually pulls ABS and trannie codes. Nothing.
Maybe it's simply age. It's decent mileage.
 
  #5  
Old 07-27-15, 07:16 PM
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od is basically torque converter lock up. best way to test it is drive steady at 45-50. and with your left foot,tap your brakes it will disengage lock up(OD). watch your rpms, they should increase 300-500. and when it engages again it will drop back down.
 
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Old 07-29-15, 07:59 PM
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will do. It just keeps bugging me. Thanks, iceman
 
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