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#49367 - 11/11/02 06:26 AM OD shifting problem
KevinNC Offline
Member

Registered: 24/09/02
Posts: 453
Loc: NC
OK I searched and found some info but not exactly. Just took my first highway trip with the "X" and had this problem. If you drove normal you had no problem but if you were going 70mph (the posted limit) and accelerated to pass, the OD would kick down. Then when you lifted throttle and slowed back to around 70mph the OD did not kick back on immediately. Sometimes I would have to let off completely and coast then she would kick back to OD. I noticed that when it seemed to hang in 3rd that if I cut off the overdrive switch and then turned it back on it would shift immediately to OD. It shouldn't take long to go from 3rd to OD after easing off the gas should it? Seemed to only do it around 70mph, no problems at 55 to 60mph. Is this normal? My other vehicles aren't like that. Why would turning the OD off then back on make it shift immediately? Not to mislead anyone, it would shift back into OD without messing with the switch but it seemed to take a awfully long time. Was the computer sensing the previous acceleration and at that mph it thought I didn't want/need OD? I mean I would let way off the gas at 70mph and it wouldn't shift back to OD and then I'd coast for a few seconds before it finally decided to shift to OD. HELP!
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#49368 - 11/11/02 07:49 AM Re: OD shifting problem
2000se Offline
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Registered: 29/10/02
Posts: 72
Loc: Prov RI
Define awfully long time?

Visit the dealer for a lookover and make sure you take it for a ride with the tech. Drive another at the dealership to see if it does the same thing.

Could be a slow solenoid or something about to break. Could be low fluid.

And, are you sure its not the TC lock/unlock cycle vs. being in 3rd gear?

Form now on, when passing someone, learn to use the OD switch. This isn't a sports car. Don't expect it to have a brain reading instant shifting transmission.

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#49369 - 11/11/02 09:03 AM Re: OD shifting problem
OffroadX Offline
Member

Registered: 17/08/00
Posts: 13692
Loc: Baltimore, MD
I'm betting he's mistaking the torque converter unlocking and locking for a shift between 3rd and 4th.

Here's what you can do to feel it out.

Cruise at 65 or so on level ground with O/D on. That should be 4th gear and just under 2500 RPM.
Now gently accellerate to 70, the torque converter will stay locked and the RPM should barely budge and you'll end up just over 2500 RPM. RPM increase should be in phase with the speed increase.
Return to 65, and this time try to get to 75 with half throttle or more. The RPMs should jump up around 3000 RPM as the converter unlocks, but speed will of course not jump as abruptly. Once you reach 75, back off the throttle and watch the RPMs fall, then settle again a second or two later as the converter locks up again.
Repeat once more (65-75), but this time as soon as the RPMs jump, turn the O/D off. The RPMs will jump a little more, but you'll be in 3rd with the converter locked up. Power will be more immediate, and the RPMs will increase in phase with your speed once it kicks down to third. Turn the O/D back on when you reach 75, and if you're not climbing a hill, the RPMs should fall in 2 stages again, once as it shifts to 4th and again just after as the converter locks up again.

Basically, if you think it's shifting, turn the O/D off. If it "shifts" again, the first "shift" was just the TC unlock, the second was the shift to 3rd gear. If you're in 3rd, 99% of the time you're guaranteed that the TC is locked up (which is better than 4th with it unlocked for any sustained period), there are only 2 ways to be in 3rd with the TC unlocked. One is if you're under 45 MPH, the TC won't lock up in 3rd or 4th...
The other time I can get into 3-unlocked is by turning the O/D off while climbing a moderate to steep grade (good) and turning the O/D back on before I reach the top (bad). The TC will unlock in 3rd and the RPMs will really wind up until you back off the throttle briefly and it drops to 4-unlocked (still bad, turn the O/D back off again and leave it off) or crest the hill and ease off. You DON'T want to run in 3-unlocked under load like this, period, the heat it generates is substantial. Don't turn the O/D back on until you've pretty much levelled out and can return to 4-locked quickly (2500 RPM at 65 MPH).

Brent
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#49370 - 11/11/02 01:10 PM Re: OD shifting problem
KevinNC Offline
Member

Registered: 24/09/02
Posts: 453
Loc: NC
Thanks Brent. I'm going to the interstate as soon as it quits raining. Good advice, I'll see what it does. wink
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