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2005 Grand Prix 190,000 miles P1811 max adapt and long shift

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PixelMagic

New member
Hey guys. I have a 2005 Grand Prix, and only once in a very blue moon (maybe twice in 6 months) my car has hard shifted between gears. I took it to a local transmission place which has been unable to reproduce the problem. The computer showed a p1811 code, which had been cleared in the past. I read on this forum that it might be a pressure control solenoid, however, the one transmission place I took it to doesn't think that will fix the problem and estimated $2,200 for the repair. He said he thinks the "clutches will be worn" even though he has not looked into the transmission.

I called another local shop (who did not look at the car however) and he said the pressure control solenoid will probably not fix the issue either based on what i told him. However, I read on this forum that 99% of the time it is the pressure control solenoid. Does my car just have too many miles on it to fix with a pressure control solenoid, or are these guys pulling my leg?
 


While it hard shifts, is it after you've been driving for awhile? My car does that once in a blue moon. And its the pressure control solenoid. Doesn't do it often enough that I care to fix it, I never threw a code though.
 
If it is caught soon enough the solenoid will fix the problem. But if its been driven like that for say 15k it's likely that clutches will be worn pretty good. If your fluid is clean and not burnt I would say replace the solenoid it will probably be fine..
 
Rob97gtp said:
If it is caught soon enough the solenoid will fix the problem. But if its been driven like that for say 15k it's likely that clutches will be worn pretty good. If your fluid is clean and not burnt I would say replace the solenoid it will probably be fine..
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Well, they said the code had been cleared a while back but was still in the computer? It is definitely possible I've driven it past 15k, but the problem first occured 4-5 months ago.

Also, how long do you suppose my car will last in this condition?
 
My Parents GP is a 01 with around 170K, and occasionally shifts hard like that. I experienced it a couple times when I borrowed it.
It started doing that around 130ish IIRC, which was around 6 years ago. It does it after being driven awhile and when it is hot out.
I'd replace the solenioid and replace with some Dex6. My Dad never bothered to look into it or fix it, that car is retired.
 
The sooner you replace the solenoid the longer the trans will last but if continued to drive with that problem with burn the trans up... I would say to replace the solenoid ASAP!! It's not that expensive of a repair apposed to trans overhaul
 


Rob97gtp said:
The sooner you replace the solenoid the longer the trans will last but if continued to drive with that problem with burn the trans up... I would say to replace the solenoid ASAP!! It's not that expensive of a repair apposed to trans overhaul
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Even if the clutches are already worn? The guy didn't look at my trans, but he said "I can almost guarantee those clutches will be worn if I opened up and looked in it." However, I don't know if they are indeed worn since the car barely gives me any trouble at all.
 
Well that's coming from a guy that want to make money! If your fluid is clean and don't smell burnt they will be fine... You would be surprised how thin new clutches are... You don't have to remove the trans to replace the solenoid
 
Rob97gtp said:
Well that's coming from a guy that want to make money! If your fluid is clean and don't smell burnt they will be fine... You would be surprised how thin new clutches are... You don't have to remove the trans to replace the solenoid
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Well here is my current situation. They ran a code check on it today, and no codes come up at all. The 1811 was a cleared code from a while back. The hard shifting problem only happens extremely rarely. I would be fine to put a solenoid on it, but my wife says since the code doesn't show up currently, and since mechanic could not reproduce the shifting problem, we should just ignore the problem.

So what do you think after all that said?
 
It's set before it will set again! If it were me I would replace the solenoid rather than ignore and need a trans overhaul in the future when u could of just replaced a solenoid and be fine. Most of the time that code/ solenoid problem is main cause of 4t65 failure unless beat on like a lot of us do then they just can't take the abuse unless built well
 
Does it shift fine when cold? Then hard when warm? Mostly hard in the 1-2 shift? If so, these are the signs of a bad PC. A shift kit is a good "temporary" solution.

My P1811 set the CEL after about 10 minutes of driving, every time I drove.
 


Bronco Boy said:
Does it shift fine when cold? Then hard when warm? Mostly hard in the 1-2 shift? If so, these are the signs of a bad PC. A shift kit is a good "temporary" solution.

My P1811 set the CEL after about 10 minutes of driving, every time I drove.
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It's only done it twice ever. In early September intermittently for about 3 hours. Then again on Saturday when I left a red light. It has never done it any other time. However, when we had the codes read at the mechanic today, and there was no code errors. However, he checked the old cleared codes (but we don't know from when) and there was an 1811 code in the old cleared codes. It has only happened twice ever.
 
PixelMagic said:
It's only done it twice ever. In early September intermittently for about 3 hours. Then again on Saturday when I left a red light. It has never done it any other time. However, when we had the codes read at the mechanic today, and there was no code errors. However, he checked the old cleared codes (but we don't know from when) and there was an 1811 code in the old cleared codes. It has only happened twice ever.
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I don't know that much about these tranny's, but maybe you are experiencing the early signs of a bad pump, or intermittent pump. Being that the P1811 is there, I would throw in a shift kit and move on.
 
Mine has done it once, but it never triggered the CEL. Over the summer, outside temps between 95 and 100, I had been driving for about 7 hours and it started hard shifting when I hit stop and go traffic. The trans was also running at about 230 degrees, my engine was hovering between 210-220 because my water pump was on its way out. I stopped for a couple hours at a rest area, when i got going again, I never had the issue again.
 
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