Ok so about a week ago I was driving my 02 impala and I heard a loud noise while driving at 30 mph and it lasted till about 50mph. well I had my dad take it down the road while I was at work about 5 days later to hear what the noise was wondering if it might have been a hub. Well I call him an hour later cause he ain’t back he says he’s at the gas station and it won’t reverse. Well apparently the noise was just my transmission being loud cause it was taking a while to shift. I’ve never had a problem with my tranny but some leakage which I think is just the gasket I just know that theres tranny fluid under my pan on one side. So I went to auto zone and they got a code for p1811. So I’m wondering if it just needs a filter and gasket change or is my tranny gone. It still shifts into gears just takes longer in 2nd and I can’t drive in reverse at all? Please help.
The code P1811 indicates that it takes longer than .65 seconds for the clutches in the transmission to engage. The computer tries to increase the line pressures in the transmission to help the clutches to engage faster, and when this doesn’t work the transmission slips and that code is set.
The transmission requires replacement.
Tester
A good inde xmission shop can say for sure one way or the other. They can test the fluid pressure, the selenoids, etc. But I expect @Tester is correct, provided the fluid level is correct, you are probably looking at a complete xmission rebuild. Not that surprising in an 02 with an automatic.
If you want to take a chance on a wing and a prayer, you could have the pan dropped, replace/clean the filter, refill with totally fresh fluid, and cross your fingers.
If you’d like to avoid this expense going forward, be sure to do the preventive xmssion maintenance recommended in the owner’s manual; and, on your next car, consider to get a manual xmission rather than an automatic. How hard is it really to press on the clutch pedal and move the gear lever? Seriously, who needs the grief of dealing with an out of sorts automatic xmission?
I really have to call you on that one. How many family sedans are available with a manual transmission? A quick google comes up with this:
These are total light vehicle sales (in millions of units) of domestic
and import car and trucks broken down by automatic and manual
transmissions:
Year Automatic % Manual % Total
1985 10,021,482 77.6% 2,887,171 22.4% 12,908,653
1990 10,141,794 78.7% 2,752,150 21.3% 12,893,944
1995 12,816,559 83.1% 2,602,211 16.9% 15,418,770
2000 15,995,874 90.0% 1,785,377 10.0% 17,781,251
2001 14,898,961 90.6% 1,540,618 9.4% 16,439,579
2003 16,752,979 92.6% 1,335,531 7.3% 18,088,510
Manual transmissions are going away and the ones that are left are almost exclusively in small economy cars, sports cars, or trucks. The sports cars and trucks wull definitely cost more to own than any automatic transmission family sedan.
Also clutches may last longer than an automatic transmission (IF and that’s a big IF, they are driven correctly), but with labor rates, etc. these days, it is still a hefty bill to replace them and you are still just as stuck when they go out. You also don’t seem to have ever spent an hour stuck in rush-hour traffic inching forward a car length at a time with a manual transmission.
Driven even halfway properly a clutch should last as long as an automatic transmission.
I suspect the main reason for the popularity of automatics is that it allows the use of the right hand for text messaging instead of shifting… 
Odds are the fluid has never been changed before and the comment about a leak also means that the transmission has probably been low on fluid to some extent and for who knows how long.
Changing the fluid may (slim chance) improve things but if the pan is dropped and there is some sludge in the bottom of it and/or metal shavings then trans replacement is a certainty.
George, guys like me do. Guys with arthritis, bad backs, and other age-related aches & pains. I drove manuals for 40+ years, but these past years the thrill has gone.
And guys like my son south of LA. He’s tired of pumping the clutch in 5mph stop & go traffic on the southern California freeways. It gets “old”.
Seems to me you don’t necessarily need a rebuilt trans
Go to the local Chevy dealer and bring this with you. Perhaps you just need the solenoid.
Perhaps the only problem is low fluid level, due to a leaky pan gasket. A low fluid level is also a possible cause of that code, as the bulletin states.
I assume you’ve checked the fluid level and it’s now full?
If reverse is gone it’s almost a sure bet you need a transmission rebuild or replacement. As the clutches in your transmission wear out the car increases fluid pressure to those clutches to keep them engaged properly. Code P1811 indicates that the line pressure has increased as much as possible but the clutches are still slipping. The bulletin above has some good information but doesn’t apply if the car has no reverse. I think you’re looking at a mechanical failure in the transmission that will require removal to repair.
@ok4450: “Driven even halfway properly a clutch should last as long as an automatic transmission.” Not too many steep hills/mountains and stop-n-go traffic where you are? Nothing unusual about clutch gone at 100,000 here.
@asemaster, I’ve replaced a lot of clutches around here but I attribute early failure to driving habits.
The clutches in the manual transmission cars I’ve owned are usually good for 200k miles and up and one on a Subaru was good for almost 300k miles.
There were a few exceptions to the rule though. The old Roadrunner and Superbee I owned went through a few…
Those must have been factory defects because surely clutch problems were not due to my driving habits… 
I understand people like the convenience of an automatic in certain driving situtations. If I lived in hilly SF, I could see preferring an automatic. But I don’t think manual xmission will go away. There are lots of people – me for instance – who will only consider to purchase a car if it has a manual xmission. I like a fiesty every day driver. And in comparing the same car with the same mpg ratings, the manual xmission will almost always be fiestier and more fun to drive, with a measureably faster 0-60 time.
@ok4450, yeah, I’ve seen some of those big old cars go through a clutch. Also, on a bad launch, I even saw a clutch go through the car. The bell housing gave birth right there.
I too think the trans needs a rebuild. No point wasting good trans fluid dropping the pan.
As far as manuals go, I’ve got to agree they can really be a pain in the Knee. I never had a problem with my VW or Morris that were sticks or any of the small car sticks that I rented, but man that Chevy Malibu was a killer. I used to trade off driving with a person that had the Chevy and I’d have to drive it the last ten miles in traffic to my work place. My old knee would crack every time I had to put the clutch in. I think it was either my age, the orientation of the seat, the throw of the clutch, or the spring or something, but I’d end up with an Ace bandage every week I had to take that car.
If it has no reverse you need a transmission. expect to pay 2000.00 to 4000.00 to replace it. sorry about the bad news LiLDevil. And fellas I don’t think you could buy a 02 Impala with a manual transmission.
02 impala? 3.8 or 3.4 motor. Uses 4t60 trans. So common. 500 used and 500 install. No way would u want to dump 2000 in and sell car in 1 yr? Ur call
I was wondering, what’s the price difference between a complete auto xmission rebuild job vs a new clutch job in a manual xmission? For an econobox, like a Corolla or a Civic? For a larger car/SUV? Anybody know?
I think I read somewhere that in the past rental companies offered both auto and clutches, but found they had more repairs with their clutch cars, so they switched to renting only automatics. But the comments here suggest that the clutched-car is at least as robust as the automatic, with clutch replacement intervals around 150 to 200K typical, which seems at least and maybe even more miles than for automatic rebuilds.