27th Apr 2008, 02:59
I'm curious if any one has had a chance to try the Pressure Control Solenoid for the 4T65E, made by a company called Borg Warner that was mentioned in the Feb 12, 2008 comment. My 2001 Buick has had three transmissions starting after it reached 55,000 miles. It now has 78,000. I paid for one, the transmission shop I went to has had to fix it twice since. I'll buy this solenoid if it really works, but I'm a next-to-poor college student and I don't want to waste even $50 at this point if I can help it.
21st May 2008, 19:09
Wow, just thought I would look up tranny hard shifts and found you all. Thanks for the info.
Does anyone know how long my car has after it starts?
23rd May 2008, 15:28
I have a 2000 Buick Century with 5200.00 miles on it, and I have a noticed once in a while the transmission shifts hard, and if you shut the car off and restart, it does go away. I think this problem happens when you drive very slow in slow traffic; this triggers it, as it tricks the computer. I think this is nothing but a computer glitch.
25th May 2008, 15:38
I have had this same issue for several years now on my 2001 Buick Century. The transmission runs smoothly most of the time, but if I am in stop-and-go traffic and accelerate slowly (instead of accelerating firmly), the transmission kicks into this mode of whining and shifting roughly. If I shut the car off for 15 - 20 seconds, the problem corrects itself. Even though I had the dealer perform the full transmission service, they couldn't diagnose the issue.
I am eager to hear if anyone has tried the suggested solution of changing the Pressure Control Solenoid and what the results were. I plan to call my dealer and independent mechanic to see if they have any additional info.
30th May 2008, 07:21
I have a 2000 Buick Century with 53,000 miles on it.
I want to know if anyone else had their Anti Lock Light come on and stay on for quite a while, and then stay off for a while.. I had my mechanic check this on the computer and they said that it could be the Anti Lock Pump or the computer... I let it go the car stops fine..
I taped a quarter over the light so it doesn't shine at me.
11th Jun 2008, 13:09
All 4T65E pressure control solenoid issues stated to date.
1. The whining noise you hear is coming from the hydraulic pump operation at maximum line pressure.
2. The hard shifts are caused from the maximum line pressure. (to compensate for a leak)
3. Each time you key off the ignition, it resets to normal until the "shift adapts" are exceeded.
4. You will most likely have a DTC 1811 (trouble code) stored.
5. A defective pressure control solenoid and/or excessive internal leaks are the main cause.
If the commanded pressure and actual pressure are correct most likely problem is an internal seal or gasket leak.
Although, I have seen on occasion and have been unable to correctly diagnose the following problem.
The PCM does not command a large enough drop in current for the given road load, thus shifts are soft and sloppy until "adapts" are exceeded and it goes into limp mode (max. line pressure).
Any ideas on why the current to the solenoid drops only to: .8 amp @ WOT and 1 amp at idle would be greatly appreciated.
29th Jun 2008, 13:37
The reason why is because it is cycling the solenoid. It switches it off and on. At wot it is allowing the solenoid to close more, hence the lower amperage.
If you had an oscilloscope, you would see the on time drop, which causes less current flow. At idle it is calling for less pressure, so it opens the solenoid longer to bleed off more of the line pressure, causing higher current draw.
11th Jul 2008, 07:25
So what is it then? Does replacing the Pressure Control Solenoid fixes the problem temporarily until it goes again. Those who has replaced this please give us your opinion. I am just so desperate now to fix this even temporarily. I plan to use the car now only for the winter season. So from now until it gets freezing cold again, I want to use the car with no worry about the hard shift and whining sound.
15th Jul 2008, 09:14
I had my solenoid replaced ($600) in October of 2007, it is now July of 2008 and the hard shifting continues to happen. I have been finding that when I add oil to the engine it stops for a while. If this is something that I can live with that won't result into something bigger I can deal with it. I am so hesitant to take it into the shop again b/c that might not fix the problem. I just hope it doesn't lead to any sort of engine failure or something of that nature. I will NEVER buy a Buick again.
15th Jul 2008, 21:01
We own a 2000 Century and the PCS solenoid was replaced under the extended warranty at about 38,000 miles, at just over three years of age. Lucky for us the dealer waived the $100.00 deductable. The problem always occurred in warm weather, city driving. The problem returned today, same conditions at 109,000 miles. The real gasser is, this car is used for about 95% of the time on rural highways- it's not like it was running NYC taxi service. I changed the filter and replaced the fluid myself, drove the car for a few days, and THEN had a reputable shop use their trans-vac to replace all the fluid at 40,000 and 95,000 miles, by the way...
18th Jul 2008, 20:13
I bought a 2000 Buick three months ago and I have the same shifting problems. I also have slipping in reverse after warm up. Is there a control solenoid for reverse?
18th Jul 2008, 21:41
The P1811 (max adapt, long shift) DTC can set because of other issues not just the pressure control solenoid (PCS). Worn clutch packs, accumulator or other internal problems. The PCM module monitors shift timing and when it exceeds.65 seconds the DTC normally sets. When it sets maximum line pressure is commanded and shift adapts are disabled. As a result you get the hard/harsh upshifts and possibly the whining sound.
One way around it is to fool the PCM module into thinking shift timing is correct. Many GM car owners have found that adding a shift kit via the 1-2/2-3 accumulator cures the issue where you can get more mileage out of the 4T65E autotransaxle and save money. Best results is obtained by switching over to the new Dexron-VI ATF in conjunction with the shift kit modification. The shift kit firms up shifting and helps keep shift timing to under.65 seconds. The Dexron VI ATF is superior over Dexron III in temperature handling.
If anyone needs a link to parts such as the shift kit or people that applied the mod with positive results, let me know.
26th Apr 2008, 02:51
April 26, 2008: I'm late in the game. I was looking for something else, when I came across these comments. I told my wife, "look what I found". Same problems with 2000 Buick Century (35k) hard shifting, trouble with electric motor in rear window; plus, my private mechanic was installing new brakes when we discovered one side of the brakes on the right rear wheel was brand new; it had never come into contact with the drum. Also the PRND21 and the mileage are now invisible, so at this point I can't tell how many miles I have on the car. Only because I want to support the American way, I just purchased a 2008 Ford Taurus. Help me keep my fingers crossed.