2001 Montana hard shifts

[olderthandirt]

Hi guys,

My 2001 Montana has been shifting hard with a whining sound. Fault code P1811 (max adapt, long shift).

I have read many posts about this on this site, along with some great answers.

I bought this van with 76K miles last year. The fluid and filter were changed about 2 months ago at 116,000 miles (it was dirty & greying, but not burnt smelling, there was no metal particles in the pan).

No improvement on the hard shifts. Two weeks ago, out of desperation I dumped a quart of Lucas treatment in it. There was immediate improvement, I did not have a hard shift for almost a week, but it is back to regularly hard shifting now.


A mechanic that was recommended to me quoted $400 to replace the PCS valve. (which is why I tried the Lucas).

I'm not really comfortable with installing a shift kit (like one man here recommends), however I wonder how helpful changing over to Dexron VI would be, over the Dexron III.

[Burkster]

Had the same problem with my 2000 .I don't think switching fluid will help since you just changed the oil. Sound like the solenoid is sticking and sending the trans pump to fulll pressure.I would try the solenoid. I let mine go too long and by the time I replaced the solenoids it was too late, I lost overdrive.(the hard shifts stripped the shaft in tranny) I got a reman tranny from GM for $1700 with a 3 year 50k warranty.Common problem with these don't wait too long it won't get better.

[merc81]

After doing the job myself, I'm not so sure what to recommend to you. Let me just tell you my experience and you decide.

I changed both the PCS and TCC valve in my tranny. It had the hard shifts, the whine, and as you say, changing the fluid only had marginal improvements. I never tried any additives to the fluid.
My van had 130k miles or so when I bought it, not sure how long it had been hard shifting before that. I did add an outboard tranny cooler in front of the radiator. This improved things quite a bit. The hard shifting didn't happen until the tranny was hot, and the cooler kept that from happening on short trips in town. It also was always worse in the summer months than winter.
Finally, my engine needed LIM gaskets that ended up being new heads, so when I did all that work, I also pulled the axle and changed the solonoids. The repair was fantastic, all problems were gone, it shifted perfectly and I thought I was beyond that problem. It all came back after about 10 months and 10k miles or so. I don't have quite the same problem as the first time. Now, it may go for weeks before it goes into the hard shift mode. Then, it stays that way for the rest of that day, but the next day the light will go out, and the problem is gone for weeks again.
It seems to be stress on the tranny that starts the problem. If driving on some of those winding, up-hill, down-hill, WV roads here, you can feel it start when the van 'surges' a bit before/after a shift. Soon, the TCC locks and the light comes on and you are stuck with hard shifting and shutter for the rest of the day. The whine is gone though, never heard that anymore after I worked on it.

I've read that the OEM parts which I used to fix the tranny are just too small and one needs to use a Sonex kit that replaces the PCS with a larger bore solonoid. I would consider doing that except the kit requires you to enlarge the body hole where the valve inserts by using a precision reamer--the reamer sells for $300+ dollars and that I won't spend on this tranny.

Currently, I've got my eye out for a junkyard tranny or a used van for sale cheap I can swap trannys with. I believe that those folks that recommend the Sonex PCS valve as a repair method are probably right, but I just am not going to sink another $300 into the tranny with no guarentee that there will be no further trouble. Clearly, I'm not into taking it to a shop either, so I'm in a wait and see mode today.

Hope my experience helps you make a decision--I love the vans, I've got 3 of them (well I have two, my neighbor has 1) and I plan to keep mine for a long time. I just can't afford to spend big $$ when there is a chance it still won't last. If nothing else, I'll replace the PCS valve again for $35 and an afternoon's effort. Its not a bad job, just tedious.

John

[rocky7]

hello merc81, could you tell me how to lower the subframe on a 01 montana to replace the epc solenoid i am tore down to that part and don't know how to support and remove. i can't remove the side case without doing that i believe.
thanks for any advice

[1Bradymichael]

Originally Posted by olderthandirt

Hi guys,

My 2001 Montana has been shifting hard with a whining sound. Fault code P1811 (max adapt, long shift).

I have read many posts about this on this site, along with some great answers.

I bought this van with 76K miles last year. The fluid and filter were changed about 2 months ago at 116,000 miles (it was dirty & greying, but not burnt smelling, there was no metal particles in the pan).

No improvement on the hard shifts. Two weeks ago, out of desperation I dumped a quart of Lucas treatment in it. There was immediate improvement, I did not have a hard shift for almost a week, but it is back to regularly hard shifting now.


A mechanic that was recommended to me quoted $400 to replace the PCS valve. (which is why I tried the Lucas).

I'm not really comfortable with installing a shift kit (like one man here recommends), however I wonder how helpful changing over to Dexron VI would be, over the Dexron III.

Mine starting doing this after I serviced the tranny this spring. It has been getting less and less as time goes by. If it does it, I just pull off the road and sit for a few minutes, which resets it, and am good to go. Ain't sticking any more into this POS

[merc81]

Rocky7,
You need to have the front up on jack stands, the stands contact the frame right behind the subframe bolts. On my silo, there is a body frame section that runs from the long frame out to the side of the van--about 6 inches long. Put the jack stand there, and as high as it will lift the car.
Use a floor jack with wood block to support the driver's side of the engine/subframe. Use the jack to lift the frame just a bit to take the load off the frame bolts. You will loosen, but not remove the two frame bolts on the passenger side and you will remove the two bolts on the driver's side.
Before you lower the side of the frame down, you must open the steering shaft linkage. This is protected by a rubber boot near the firewall on the driver's side. Its a $#%@% to slide that boot up into the firewall, but if you use soap and water and clean the boot up real well, it will slide clear up into the firewall hole and out of the way so you can remove the linkage screw.
The steering shaft will also slide clear up into the firewall out of your way once you remove the linkage screw and maybe pry apart the ears of the shaft clamp to make it loose. You also need to remove both sides of the stabilizer bar from the swing arm supports off the supension.
You do need to have the half shaft removed, and the plastic shields behind the wheel well. The ABS sensor wire clips on back there, so that needs removed as well. There is a cable connector just above the removable splash shield to disconnect it.

That's roughly what needs done; assuming you already had the top engine mounts removed. The gasket on the side panel is very expensive, don't pry on it when opening the case and it will be fine to reuse. The connector at the top of the tranny is tricky to get off. It just needs squeezed at the 3 & 9 positions and it will unplug. I found the bolt heads along the bottom edge of the valve cover were large torx which I had to go purchase a tool for. These were really hard to get off for my van.

Once open, keep it clean around the valve body. You do have a diagram for which solonoid is which? I had to remove the tranny fluid pump to get at one of the valves, can't recall which that was, but if you remove the pump, be sure to keep it from sliding all apart while its off and then make sure it seats correctly on the way back on.

I'll keep an eye on this post if you run into trouble.
John

[jwright76]

Hey Guys,

Speaking from experience, and a former aamco employee, do not waste money on Pressure Control Solenoid for code p1811. It will help some with code p1870 if not too far along. What is happening when computer sets the p1811 code is the computer is commanding the transmission to shift and then monitors the time in which it takes to mechanically complete the shift. If it takes too long to shift
(i.e. worn clutches most commonly) it set this code and goes to a default mode which increases the transmission line pressure to its maximum level and causes hard shifts. Usually most noticable on the one-two shift. At this point the transmission needs rebuilt or replaced. However it isnt unheard of to drive a vehicle with this condition for an extended period of time, just have to tolerate the hard shift.

[shampooguy]

One more vote for the shift-kit solution. I also had the hard shift problem, 1-2, 2-3, often occuring after 10 minutes of driving. I followed the steps outlined in this thread:

http://www.automotiveforums.com/vbul...=zzperformance


I probably spent $100 in all after the Dexron VI (12 qts Walmart $3.77), seafoam transtune $10, shift kit $30, LubeGaurd $11, and a good 4 hours of work time, some of that flushing out my eyes (note: do not push on the springs in the whatchamajigger, it will spit tranny fluid in your eye).

Mods, this seems like a common problem...should one of these threads be a sticky?

[tmacguire]

Did it fix your problem? Do you know if this 4T65E is the same as what's in the 2001 Montana? Mine has not shown any codes but is doing some crazy shifting like some of the previous post. I am wondering if this would correct my problem. Thanks in advance.

[spike88]

.

I was chatting with my Transmission mechanic the other day. He explained the 4T65E transmission is a "general" grade transmisison that is good for the short term. But for longer life, it does develop problems. Miss shifts, hard shifts, etc. etc. For more details, surf entire contents of: http://www.tripleedgeperformance.com...sion_Info.html

He told me that when hard shifting starts to happen (hope it never does to my van), I need to change its transmisison fluid (with new stuff) ASAP and add Lucus Transmission Fix addititive. re: http://lucasoil.hodgsoncorp.com/slip...ansmission.htm If mixed in with new transmission ATF oil, it does "buy some more time". Sometimes 6 months and sometimes up to 12 months. But in the end, one's transmission needs to be repaired / serviced. Luckily, there's many different "performance kits" available for the 4T65E. If one is going to rebuild a worn-out transmission, one should pick the approprite performance kit for their driving needs. For example, HD kit for towing trailers, high RPM kit for aggressive drivers, etc. etc. Also install a new appropriate driving condition torque convertor as well. Not all torque convertors are the same either.

My transmission mechanic also recommended that if one hauls stuff with their van, often has 3+ more adults, lives in a hilly region, does lots of stop/go traffic, then one "must" install an Aux Transmission cooler as well. For example, 11"-11" LPD design - which is made for towing 3,500+ lbs trailers. re: http://www.makcotransmissionparts.com/OC-1679.html Yes. This size of Aux Transmission cooler is "over kill" for the `average` 2 people within van driving conditions but if one is going to buy/install an Aux Transmisison cooler, one should spend a few more dollars and get a larger then needed size. Thus, keeping their transmission oil cool. As he put it, "Cool(er) transmisison oil = longer life for the 4T65E transmission" Thus, why I plan to install an Aux Transmisison cooler (as seen in above URL) in my 2009 Montana van within the next few weeks.

With the above items in mind, one might want to install some new (clean) transmission fluid and install some Lucas transmission Fix fluid as well. Then, start looking for competative priced transmission repair shops. If hard shifting, it sounds like one's transmission needs an OEM rebuilt (OR possibly upgrade to Performance Upgrade Kit - based on one's unique driving conditions) as well.

Hope this helps as well....

.

[shampooguy]

I'm not exactly sure which one of the steps fixed the problem, either the synthetic fluid, new filter, additive, or the shift kit. I figured since I was dropping the pan, I would install the shift kit too.

In a couple thousand miles of driving, including a 28 hour round trip to Myrtle Beach, zero hard shifts.

Originally Posted by tmacguire

Did it fix your problem? Do you know if this 4T65E is the same as what's in the 2001 Montana? Mine has not shown any codes but is doing some crazy shifting like some of the previous post. I am wondering if this would correct my problem. Thanks in advance.

[shampooguy]

Thanks for the link...while I may have temporarily fixed the hard shifting, I also have the problem outlined in the first paragraph of the "Problems" section of the website you provided, "Neutrals at stops". Strange thing is, I cannot replicate the problem when I manually drop the transmission into first.

Originally Posted by spike88

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Miss shifts, hard shifts, etc. etc. For more details, surf entire contents of: http://www.tripleedgeperformance.com...sion_Info.html


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