My 2004 Venture transmission starts to shift hard after driving about 8 miles(14km). I noticed if I shut the engine off and then restart it immediately the hardshifting stops. The transmission/engine does not really have a chance to cool down. This tells me that it may have something to do with the computer. Its almost like it is resetting itself after I shut down and restart.
Anybody have any clue??

Dan in Canada

 

When you shut off the engine, pull the key and get out of the van, the computer resets the drive cycle. When you start the van and start moving again the computer checks the length of time it takes for the trans to complete a shift. If it's longer than 65 milliseconds, it increases the pressure. It will do this 5 times (so I've been told) before it gives up and changes the pressure to maximum. This makes the pump whine and the shifts jarring. The computer will store the code P1811 each time this occurs.

I know you already found the thread that explains this, but I'll put a link to it for anyone else who might be having this problem.

https://chevroletforum.com/forum/venture-29/venture-transmission-2069/

 

The problem with the transmissions in these vans that cause them to hard shift is the pressure regulating solenoid. It cloggs up and causes this symptom usually between 60-100k miles. I was lucky and was able to do a transmission service and flush on mine and it removed the build up and has been shifting fine now for months. You may have the same luck. If not the solenoid will need to be replaced which is a fairly involved job involving the removal of the cover on the drivers side of the transmission. If changing the filter and flushing it doesn't get rid of it you may want to try an additive before giving up on the easy way. good luck!

 

Hello everyone. I have owned 8 of these vans over different years and I have found a solution to the hard shifting that does not require an expensive fix.
The pressure control module is the problem but it is getting a signal from a dirty Mass air flow sensor.

Now all you have to do is buy a spray can of mass air flow control cleaner and take out your MAF sensor and spray clean this really well and put it back in and it will no longer send your computer a signal saying something is wrong and screw with your pressure control module.

It is a special cleaner that leaves no residue on the MAF sensor readily available at Canadian tire or parts store.

I know this might be hard to believe but believe an experienced Venture owner. Been there done that.

The MAF is in the tube from your air cleaner to the intake.

Hope you have success.

 

I have owned 04 Venture 13 years. Had hard shifting at 75k miles. Pressure control solenoid went bad and had replaced. All good until 138k miles and hard shifting again. No error codes and mechanic said it may not be solenoid. I researched online and found this thread. I cleaner my air flow sensor (very dirty) at 140k. Instantly fixed my hard shifting. Thanks!

 

Well I was able to fix my hard shift by changing coolant temp sensor. Tranny was getting too hot then issue would start. Usually after sitti v at long light. I was able to confirm this by driving around for couple days with climate control on defrost. This arrives ac compressor which turns both fans on. Problem stopped. I then repla ed sensor, set climate control off defrost, drove fan for 1 day and problem didn't return. Hope this helps.

 

I have a 2004 Chevy impala that I’ve been working on for the past 4 months but I can’t seem to figure out why it sometimes shifts hard in 2nd and 3rd gear also I can seem to find out why my reverse lights are not working

 

Thanks, your information was very concise. I'm gratefull I found this site.