DanOttawa

Hi chevydriver. I am getting hard shifts and code P1811 on my 2004 venture. I have 71,000 miles on it. A transmission shop suggested trying Transgo shift kit (accumulator portion only). Did you have any luck solving the hard shifts with your Transgo kit.

Dan

jhs3eva

DanOttawa, check out this web site:
http://www.tripleedgeperformance.com...ft__P1811.html

and this discussion board thread:
http://www.grandprixforums.net/f21/4...ion-25211.html

I did go with the accumulator portion of the shift kit and would recommend it (mine is a 2000 and it started with about 65-70K on the transmission). It immediately made the van shift better (and faster) and I have not had one of these "episodes" for about 10K miles now.

I will add, however, that I now (last 500 or so miles) have a TCC lock up problem (dropping in and out). I have yet to diagnose it but I don't think it has anything to do with it. Either way - all automatics get rebuilt eventually (or go to the scrap yard). So even if the shift kit just buys time, then that's something. And the money on the kit isn't wasted b/c, IMHO, that kit should go into a rebuild anyway.

All of that is assuming that you want to keep the van. I keep mine only b/c I can't spend $$ to get anything else. If I could I would. This thing is the biggest piece of junk I have ever owned.

Bogushavis

Hey DanOttawa, I have a 2004 Venture with 103,000 miles on it. This van has been very well cared for and started the "hard shifting loud pump whine" several months ago when the trans was hot after a long drive. I took it to a regular shop (not a trans shop) and had them look at it.

They pulled the P1811 long shift code from the computer and said it had been tripped 25 out of the last 100 drive cycles. They wanted to rebuild the trans. They told me that the trans was coming apart and were sure they would find metal in my trans filter. I've changed the fluid in dozens of transmissions, and they all had at least a trace of metal in the pan. They never said anything about the pressure solenoid.

I changed the fluid and filter myself and adding TransX. This made the problem much worse. Instead of 25% of the time, 90% of my drives resulted in a hard shift episode. I have one route that will trip it 100% of the time, hot or cold.

I bought the Transgo kit and put it in last Saturday ($60 with shipping). It was very easy to install. The upshifts feel about the same, maybe just a little firmer. The downshifts are much firmer. We drove the van around Saturday and Sunday with lots of stop and go and the hard shifting did not occur even once. So far I'm very satisfied with the Transgo kit.

The shop told me that P1811 is thrown after 5 shifts that take longer than 65 milliseconds. The computer tries to up the pressure gradually to shorten the shifts. After 5 tries without success, it throws the code and maxes out the pressure. I've read elsewhere that this failure could also be worn or glazed clutches. If my clutches are the problem, I guess I'll know soon enough when one of the clutches completely fails .

I printed some additional instructions for the DIY shift kit which proved helpful when removing and replacing the accumulator.
http://home.pacbell.net/chris-5a/DIY...uid_change.pdf

{Update 12-30-2010: driven daily for ten weeks with no hard shift episodes. Downshift firmness has softened. Most likely due to the computer retiming the shifts. However, 3/4 or more throttle while in second gear that initiate a downshift causes a problem; the trans drops to first but does not engage immediately. The engine races and the clutch grabs hard and spins the tires. Then the trans seems to forget what gear it is in and will not downshift properly to first when stopping; starting from a stop it slams into first after about three feet. I'm not sure if the trans is out of gear or still in second, pulling the shifter into "1" eliminates the problem. Shutting off the engine and pulling the key resets the computer and this stops. This only happens to me, my wife never drives the van this way. I would like to take the accumulator apart again and replace the springs on the cover side of the pistons with new stock springs. Those springs did not come in the kit and I would feel better with all new springs. This problem also occurred after a 1 hour freeway drive. Stop at a light and when you try to accelerate the trans free wheels for 1 second and then shifts into 1st gear very abruptly. I should have had the PCS replaced.}

chris_four_cars

I have an '04 Venture (88k miles) that has the intermittent rough shift. There's no rhyme or reason as to when it will occur (hot/cold, driving conditions, etc). A national transmission shop told me it needs to be rebuilt ($2600), but a local place said he gets them all the time and that the pressure control solenoid will fix it. I'm leaning toward believing he is correct but I hate to spend the $350 he wants for the solenoid if I'll need a rebuild later anyway. Any help is appreciated.

capucine

Christ: considering your low milleage I dont think you need a complete rebuilt. These solenoids are the culprits. I hope my 2009 uplander will not end up like my 2003 impala which gave me tons of troubles with the transmission but my millage was 166,000 kilometers much more than your venture. So far with my uplander I have 36,000 kilometers and the transmission is perfect

jhs3eva

I would stay far away from national transmission chains. As franchises they can vary, but in general they tend to have one answer no matter what the question is: "you need a rebuild." Then the rebuilds aren't always good.

All intermittent rough shifting is not created equal. Does this come with a P1811 code? A noticeable whining sound? Will it seem to "reset" itself if you shut it down & start it back up?

If so, then I would ask the local person the do the PCS, but also to install shift kit springs/spacers in the 1-2/2-3 accumulators (Transgo is one). The pan should be coming off anyway to do the PCS, so they will be halfway there.

Just FYI: my local transmission guy said he doesn't touch these things anymore. No matter what he does they too often come back with problems. I'm surprised your local guy is so confident about the PCS. I think my local guy needs to be doing shift kit work whenever he does a PCS.

Bogushavis

If your local guy says that the PCS will fix the problem, then it's likely your van is tripping the p1811 "Long shift" code. The computer times the shifts and tweaks the line pressure if they are too slow. It makes 5 attempts to increase the pressure and thus quicken the shifts, then it trips the code and sets the pump to max pressure. Apparently, tweaking the line pressure is the job of the PCS. You will hear a whine in the pump especially in first gear, all shifts will come with a hard thump regardless of speed or throttle position.

I have a friend who had his PCS replaced and it was fixed, 10k miles on the fix so far. I fixed my '04 Venture with the Transgo shift kit. I'm still having some problems, see my "lengthy" post above. If I had to do it over again, I would have gone with the PCS and the Transgo kit.

Everyone around here wants $600 to replace it. The transmission has to be partially dropped to replace this part. It is not in or behind the drain pan, it's on the valve body on the side of the trans.

Tad

My transmission, after having Aamco rebuild it, is doing the same thing, this started within 20 miles of leaving their shop, and at the same time the speedometer starts acting up. Aamco told me it had to be electrical so I had Chev dealer check it and they told me it was the computer but after replacing computer it still didn't fix the problem. Aamco did another rebuild and I picked the car up yesterday and within 20 miles is doing the same thing. Any help with this would be appreciated.

jhs3eva

All I can say is to read this whole thread. Its all in there somewhere, including the fact that national transmission chains are not the best places to go, and even if this is a good franchise location that doesn't mean they will be able to sort it out. GM made a transmission that even they don't seem to understand. I believe that the first "official" word from them was the pressure control solenoid. Sometimes that makes a difference but it doesn't seem to be the standard answer anymore. Everyone shrugs now, including GM. (Replacing a computer, btw, is almost always a shrug kind of an answer - "well, we don't know what else it could be...")

What - exactly - did AAMCO do when they rebuilt it? As in what parts were replaced? If your problem is actually common one that comes with the P1811 code then AAMCO likely assumed that your clutches were shot. Did they put in a new EPC solenoid? Did they install any of the many upgrades and fixes for these transmissions (such as those made by Transgo and Sonnax?) If they just stuck new clutches and seals in it, its no surprise that this didn't fix it.

Do you know how much time they actually spent on diagnosis? The control of these transmissions is very complex, and that includes the control of the line pressures which itself is related to things like shift time/shift quality. The information for controlling these things comes from the engine (such as the throttle position sensor and mass airflow sensor). Problems in those places can be the root cause of transmission problems.

Anyway, I'm sure AAMCO is giving your transmission routine and generic service whereas this complete engineering disaster from GM requires either a scrapyard or a tech who is highly experienced with these pieces of junk.

Trainingdragon

I know this is an old thread, but my mom's 04 Venture is now having this problem with only 40,000 miles. Does anyone have a procedure with photos or a video on how to replace this solenoid? Does anyone know the part number? Should this be part of a trans rebuild or can you just replace the solenoid?

thanks.