Transmission - Rough Shifts and Whine

2000 Lumina, 110K miles.

1. Loud whine all gears, audible even at cruising speed and in park.
2. Rough shifts all gears.
3. Shifting from drive into neutral at speed initially feels like a downshift, then feels like neutral.
4. Intermittent. May happen 5 times a day, or once a month.
5. Cured by turning off ignition for 15 seconds and re-starting. (usually)

A thread in another GM forum described a Pontiac with SOME of these symptoms and the advice was to replace the Pressure Control Solenoid Valve assembly in accordance with TSB 0O-07-30-002B (which also covers 2000 Luminas).

I have not yet checked the computer codes, but assuming I get a code P1811 or P0748, is this the same problem that the TSB addresses or something entirely different?

You are right on target with your diagnosis/thinking.

Thanks for the quick reply maxwedge! If the codes come back as expected, I guess I'll be replacing solenoids soon. If not, then I'll be back to play "Stump the Experts" some more.

BTW... impressive profile and number of posts.

Hello Rick,
I too am having the same problem on a 2001 Century. I am a ASE mastertech. I have followed the bulletin: repl pc sol, and tcc pwm sol.
Has NOT fixed the concern. In the past we have replaced the valve body, but have still had repeat symptoms. I called a very good aftermarket rebuilder, he has nothing else to offer.
If anyone out there has more info, PLEASE help!!!!

Funny you should mention replacing valve bodies. I had a 98 GMC Safari Van that developed rough shifts from first into second gear. No other symptoms like I'm having on the Lumina.

After consultiing other blogs and the local GM service tech, it seems that on this particular transmission (the Safari van that is) the valve body problem is common. I replaced the valve bodies on the van and it solved the problem.

But, the symptoms on the Lumina (except for rough shift) are entirely different than the Safari van. Since the problem is intermittent, that makes me think it would NOT be valve bodies like on the van. Also, since the problem can be temporarily cured by re-starting the car, that also makes me think electrical vs. hydraulic or mechanical.

Bear in mind that my post is merely amateur brainstorming by somebody that can barely twist a wrench.

A full scan with a trans function scanner will answer some questions, you may see a pending trans code for the Pcs solenoid and also look at other internal functions.

I beleive that the powertrain module is reacting to excessive torque converter slip speed. This is monitored by the pcm and is kept rather low
(15-40rpm) at highway speeds. If a low number cannot be maintained the pcm decreases amperage to the pc solenoid.This causes higher pump/line
pressure, and is felt as firmer shifts. Additional pump oil volumne is also bypassed causing the "whine". It resets after key is cycled.
I have replaced valve bodies per GM tech assistance to correct this condition in the past. Their thoughts are that valve to body wear is allowing oil to seep past the apply valve causing the excessive slip rpm.
I too am still looking for that Super tech" that can shine a new light on this very common problem.
The bulletin about the pc solenoid replacement is not addressing the
root cause to this condition.

Agreed on the worn TCC valve bore, but if the pcs is stuck then this would acct. for the condition, if it is responding to the p1870 condition then this takes a different direction, hence the recommendation for the full scan.