2000 Montana - Sporatic tranny problem - code 1811

[NFred]

HELP!!

Have a 2000 Montana with 90k miles. Just started w/ sporatic hard shift of transmission, but only after it has been driven for a while (30+miles) and only after shutting off & restarting the engine. And, this doesn't happen every time. Took it to local shop (with "trusted" mechanic) who said fluid looked more like 125k miles color-wise and said a tranny flush may solve problem and give another 30-50k miles. Did tranny flush. Mechanic also noticed leak in intake manifold, so just spent $1200 for gasket replacement, new spark plugs & wires, thermostat, & air filter. Well, 1 wk later, sporatic shift happening again. Has code 1811. This mechanic does not do tranny repair but called tranny shop for me. They said no reason to replace PCS as it's expensive and may not solve the problem (said they have to drop the whole tranny which dealer said is not true.) Of course, they recommend tranny rebuild at $19-2100 w/ 24month/24k mile warranty. Dealer says may be PCS and need to "test" ... $500-700 to replace PCS, much more than $2100 to rebuild ("won't know until get in there...")

I've been doing research and would like to try the Seafoam, but I'm not a DIY for this and wouldn't be able to "drop the pan and change the filter" afterwards.

Oh, the "trusted" non-tranny mechanic that just did the flush <300 miles ago said his only hesitation about it being the PCS is that the new fluid is already changing colors, so that would make him think rebuild needed since he just power flushed it. Maybe I should do the Seafoam then have him flush tranny again and change filter?

So, should I do the PCS replace and hope it solves it or just take to tranny shop to do the $2100 rebuild?

I'd like to get at least 2 more years/25k miles out of this vehicle.

Any thoughts would be greatly appreciated!!

[merc81]

In my experience, if the problem is just now starting, you have a long way to go before the van becomes unusable if ever, due the to pcv (pressure control valve) sticking.

Its an annoyance, not a killer. I purchased an aftermarket tranny cooler and installed that in front of my radiator. This helped a lot. I changed the fluid/filter and that helped not at all. . .

In the end, I changed out the TCS (torque converter solonoid) and the PCV (pressure valve) myself at home. It wasn't that big a deal, just took several days to do. The parts cost me $50 bucks.

The tranny ran like brand new for about 8 months. Now its started to act up again although this time it takes spells were it has one bad day and then works fine for a couple weeks.

I'm not real happy with the hard shifts, but I'm not anxious to do the job again. I've read on this board that to get the thing to stay fixed, a bigger valve needs to be installed. This requires a larger bore hole in the transmission body and the tool to do that runs about $300 bucks. Its a precison reamer and I can't locate one anywhere to borrow, so that job is waithing in the wings and I'm back to the occasional hard shifting.
It works better in the cool weather, so the tranny cooler will help out more than you think--its cheap at $50 bucks and takes only an afternoon to install. It won't fix the problem, but will delay the time when you can't stand it anymore.

I'm keeping an eye out in the junk yards for a used one I can get and try the oversize valve replacement routine on. I'm never going to pay someone $2k to rebuild the tranny only to have the same thing happen again.

Like I said, if you want to change out the solonoids yourself, it takes $50 bucks or so and an afternoon's work. You need to pull off the driver's side wheel, remove the bolts through the strut and take the drive shaft off. The steering shaft gets unbolted as well.
After that, the subframe lowers down on that side and the trans cover gets removed. Piece of cake

[chris_eitniear]

You might also try the steps outlined in this thread: http://www.automotiveforums.com/vbul...d.php?t=899929

Its in the Buick forum, but its the same transmission, and the mod suggested there worked on my 2000 Montana. The most expensive part was the Dextron VI. I think the shift kit was about $30, and it took me about an hour and a half to do the work myself.

[merc81]

So Chris,
I've looked at what I think is meant by a 'shift kit'. If I'm understanding the post correctly, this is some sort of performance mod that is done to the springs in the acccumulator shown in the photos? The shift kits I've been able to locate on the web indicate they are intended to reduce the shift times thus making for somewhat of a harder shift, but increasing life of the tranny. Is this what you did to your van?
How did this work out for you?

I'm interested in this since as I mentioned above, I already changed out the solonoids in my 4t65e and 12000 miles later I'm back to the problem.

[NFred]

Thanks for the replies. I had read the thread about the shift kit, but I am in no way a DIY-er. I'm now thinking I'm going to get the car to the dealer for their opinion, and probable PCS change. The tranny shop did not want to do the PCS change and just pushed for rebuilding.

I've read that the PCS problem reappears as Merc81 confirms, but even 2 PCS changes is cheaper than a rebuild ... plus I've read of rebuilds where this reappears. Thanks for posting that you've gotten 12000 miles out of the van after the PCS change. I want to get about 2 more yrs/24k miles out of this van, so maybe I'll get lucky. Will they have to change the fluid when changing the PCS? Would it be worth it to buy some Seafoam trantune stuff to put in there before the 25 mile drive to the dealer? Of course, then the darn thing wouldn't "at up" for them!

Should I add the Seafoam after I get it back? Is it preventitive or is it harmful to leave it in there?

[chris_eitniear]

Originally Posted by merc81

So Chris,
I've looked at what I think is meant by a 'shift kit'. If I'm understanding the post correctly, this is some sort of performance mod that is done to the springs in the acccumulator shown in the photos? The shift kits I've been able to locate on the web indicate they are intended to reduce the shift times thus making for somewhat of a harder shift, but increasing life of the tranny. Is this what you did to your van?
How did this work out for you?

I'm interested in this since as I mentioned above, I already changed out the solonoids in my 4t65e and 12000 miles later I'm back to the problem.

Yeah, that's pretty much what I did. I put the Seafoam in and ran it probably about 300 miles before I did the pan drop. I don't know if I'd call the shift kit a 'performance mod' as the shifts are only slightly firmer than stock, but the firmness of the shifts are dependent on the size of the spacers you put in. The kit I got from ZZPerformance had several different sized spacers included, and even decent documentation about which sizes caused firmer shifts.

I used the spacers that created the least firm shifts in the kit, and really, the shifts are barely noticeable. I've run the van about 6000 miles since doing the mod and have had no further troubles with the trans.

I probably put around $100 into doing this mod, with the Seafoam, shift kit, filter, and Dextron VI ( I couldn't get the Supertech fluid at $3 a quart, and had to use Castrol at almost $6 a quart - ouch ) For me, its been well worth it.

[merc81]

Will they have to change the fluid when changing the PCS? Would it be worth it to buy some Seafoam trantune stuff to put in there before the 25 mile drive to the dealer?

Absolutely. Changing out any of the solonoids requires opening the side cover. That requires pulling out the drive shaft on that side and letting most of the fluid fall out. If it doesn't all pour out via the shaft opening, the rest will come out when the cover is removed. Hard to say if they will flush out the remaining fluid in the torque converter and pan, I'd hope so but you should ask them to.

I've never seen the Seafoam stuff; I'm gonna go look for it today. Chris says he ran it for about 300 miles & then flushed it. You say your not really a DIY guy so flushing it out will be a problem--you need to remove the lower pan and the gasket then needs removed & cleaned as well as both mating surfaces; it takes time and care. If you are going to do this and have the shop flush it out, you better talk with them about it first so they know its in there.

[fritcr]

My 2001 Montana tranny is acting up. I don't know how to explain it really. Seems like it sort of lurches or something when taking off or when kind of rolling through a light? Hmm I don't know if I'm explaining very well but it is not shifting right. My wife usually drives it so I'm not sure really if it is shifting hard. I know it shifts harder than my Grand Prix. We have not had the Montana for very long so I don't have any thing to gauge it by. It has 91k on it. I figure it needs a pan drop anyway. I was thinking of putting the sea foam in first and letting it run a bit then doing the pan drop. My question is...does it have to be "flushed" out or will the pan drop be ok. I have no way of flushing it at home of course. Now after all this reading...I'm wondering if I should do the shift kit too? Any suggestions. I am pretty good at diy stuff and should have no trouble putting the kit in and changing the fluid.
Rob

[wafrederick]

Sonnex makes the upgrade kit for the 1811 code.Lucas is another product great for transmissions,like STP and it will free up the valves in the valve body.Where I work at,we use Lucas products which do work.Dropping the pan,replacing the filter is the best thing to do over a flush.You will pay for more expensive repair after a flush was done.I know a transmission shop that does lots of valve body cleanings and rebuilds due to flushes with the machine.