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2001 Grand Prix tranny

B

Bowtie01

New member
Hi folks,
I'm looking for some help!(as everyone is!)
I have a 01 Grand Prix. When I got the car, it would barely run at more than an idle. I did some checking and determined that the catalytic converter was plugged. I replaced it and most of the exhaust. Problem solved. The next issue was random RPM spikes, in park, or while driving (very dangerous!). I found this problem to be the idle air control valve. Replaced and all is well now with the engine. My next issue is the one I'd appreciate some input on. The car will not shift into fourth. The torque converter will not lock up either. This of course results in poor fuel economy since it does 3400 rpm at 120km/hr. There are no codes in the computer. I am suspecting a stuck 3-4 shift solenoid. I would like to know if anyone has encountered a similar issue and what the cure was. Is there possibly a problem with something on the exterior of the trans(shifter position, wiring etc) that I can check before I dig into the solenoids? I believe that a wiring issue would throw a code, is this so? The shift indicator is fine.

I thank you and appreciate your help!
 


If the shaft was stripped, would the car still try to shift to fourth and get a "neutral" type result? Should I find shrapnel in the filter/pan?
 


Does the trans use the fourth gear shaft in addition to third gear? If not, again I ask, wouldn't there be some slippage or some other neutral type of feeling? If the shaft is worn, how would that affect the lock-up in other gears? My torque converter isn't locking up in any gear. To me, that seems to be more of a pressure/solenoid issue.
 
When the 4th shaft strips you just lose 4th gear, no other side effects and it will just remain in 3rd range. Just as if 4th gear was working- when you let off the throttle the rpms will settle down a bit as there is no engine braking or elements applied to connect the engine constant to wheel speed. When you put your foot back on the gas pedal it will rev back up to catch the gear. TCC should still apply as this is not effected by a stripped 4th clutch shaft. There is not a sole-function shift solenoid that only controls the 3-4 shift, so as long as 1-2-3 works as it should then the shift solenoids are all working fine. There are two shift solenoids total and are used in various combinations to make all gears operate. The shift solenoid strategy should be listed on the Tech Info page of our website. Watching live transmission data on a scan tool will verify that the pcm is commanding a 3-4 shift and you can also watch the "current gear ratio" parameter to compare the commanded gear to the ratio. Losing 4th gear will not set a code but the pcm will continuously ramp up line pressure to try to make it apply even though it physically wont.
 
Finally!! Some real technical help!!! I really appreciate it! Is there going to be physical evidence to prove that it is a worn shaft (shrapnel in the pan)? I think this will be a trans removal job to repair? Do you have any other suggestions as far as component replacement while I have the trans apart?
 
The shaft over time wears down and then you no longer have that gear, you likely wont find and piece of metal in the bottom of the pan. Just lots of clutch material on the pan magnet. You'd have to pull the shaft out of the trans to see the damage.

You can do the side cover remove in the car or out of the car. There are write up's for both in the "how to" section.

Depending on how many miles you have on the car, a full rebuild with new parts, clutches etc etc might be a good idea.
 
Bowtie01 said:
Finally!! Some real technical help!!!
Click to expand...

Finally? Searching for the issues would have yielded you results much faster, not beating you down just making a suggestion if the timing wasn't as fast as you'd have liked. This is a very common issue and documented a lot on this and many other sites. Searching will also provide you with a write up I did on how to fix the 4th hub in the vehicle.

(add the word "eas y" without the space to the search box)
 


Right up at the top is a magnifying glass. Click on it and that'll bring you to the advanced search. If....that doesn't seem to net you results, use my name and eas y without spaces. Most likely you'll find something. If not, please have some patience.... we help for free and have good info, but sometimes we have lives as well.
 
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