Friday, June 28, 2013

Fixing My Van's Transmission

When we got a 2005 Pontiac Montana (with has a 4T65E transmission) from Mel's parents I knew there would be some work involved with getting it up to snuff, but I certainly wasn't counting on having to fix the transmission.

From the first time I drove the van I noticed that it would shudder on take-off if I hit the gas pedal a bit harder than usual but it would eventually kick into gear and take off as you'd expect. Also, once the engine warmed up I noticed that the shifting between gears got very hard and almost immediate with a fairly hard kick so I brought it into Mr. Transmission who did a free scan on the tranny and found the much dreaded and very well known P1811 code (Maximum Adapt and Long Shift).

Basically what that means is the computer determines that the shifting between gears takes too long (>0.65s) for whatever reason and tells the switch that regulates oil pressure to the gears and clutches to put maximum pressure on it so it wouldn't take too long and burn out the clutches.

After some thorough research and finding some really good articles I determined that the most likely cause for the shudder and hard shifts is the electronic pressure control solenoid (EPC) also known as pressure control solenoid (PCS). Luckily the part alone is less than $30 bucks on eBay but the labor to replace it is listed at 6-8 hours at a transmission place (Mr. Transmission quoted me $1200 bucks), it'll obviously take longer for someone who doesn't do it every day.

I ended up buying and installing an external tranny oil cooler ($60 bucks at Mr. Transmission) which took a good 3hrs of labor, but it greatly extended the time until the hard shifts would manifest. It virtually eliminated the symptom for any drives under an hour but I knew it was just a temporary solution because the real problem wasn't fixed, it was just simply masked by keeping the oil at a lower temperature.

Here are the two links that helped out a lot, particularly the first one:

Solenoid Replacement Link
Transmission Fluid Flush Link

After much humming and hawing, and considering that I'll be driving to Ontario and back this summer I decided to take the plunge and buy the EPC solenoid. However, since I would have the tranny cover off already and easy access to all the other solenoids I figured I might as well spend the extra $75 bucks and buy not just the EPC but all the other solenoids as well (TCC solenoid, shift solenoids, and the TFP switch). I found the entire kit on eBay for US$88 plus shipping which came to CAD$138.93 and arrived within less than two weeks.

Difficulty Level (Easy, Medium, Hard, Insane):
Medium, just very time-consuming

Since the process was so involved and had so many steps, I knew I couldn't keep it all in my head so as I took each component off the van I wrote it down so I could follow it backwards when installing. Here are my personal notes:

1.    disconnect battery cable
2.    disconnect throttle cables (2)
3.    loosen both engine torque mounts(15mm & 13mm)
4.    remove air intake duct & plugs
5.    remove maf
6.    jack up car
7.    remove both tires
8.    remove axle nut (L)
9.    remove wiper cover
10.    remove brake caliper & rotor (L)
11.    remove strut to steering knuckle bolts (2x11/16")
12.    disconnect tie rod end (L)
13.    remove axle (L)
14.    remove plastic wheel well cover
15.    remove radiator shield at bottom (4x10mm)
16.    remove felt steering column cover inside (L)
17.    disconnect airbag plugs (1 under steering column cover, 2 under seat L & R)
18.    remove stabilizer bar (15mm)
19.    disconnect abs plug (L)
20.    disconnect tie rod end (R)
21.    remove sway bar bushing brackets
22.    remove sway bar
23.    remove rack & pinion bolts (2x11/16")
24.    remove rack & pinion heat shield (2x10mm)
25.    remove left motor mount bolts (2x15mm)
26.    loosen right sub-frame bolts (2x18mm)
27.    support sub-frame with jack
28.    remove left sub-frame bolts (2x18mm)
29.    disconnect exhaust hanger
30.    unhook oxygen sensor cable
31.    remove transmission pan (10mm)
32.    disconnect main tranny connector plug (push in at 3 and 9 o'clock)
33.    remove steering column pinch bolt
34.    open wire clips on top of engine
35.    remove strut to steering knuckle bolts (R)
36.    lower engine
37.    remove tranny to subframe mounting bracket (4x15mm)
38.    remove tranny cover bolts (13x10mm, 4x torx)
39.    remove tranny side cover
40.    replace EPC (PCS) solenoid
41.    replace TCC solenoid
42.    replace 1-2, 2-3 shift solenoid
43.    replace 3-4 shift solenoid
44.    replace fluid pressure switch (8ft/lb torque)
45.    installation is reverse of removal


This one is the simple removal of the 3-4 shift solenoid, the others were just as easy

This one is the re-installation of the new 3-4 shift solenoid


The kit I bought on eBay
After the wheel, brakes and axle were removed
The old and new sway-bar (stabilizer bar) link kit
The old one snapped as soon as I tried to loosen it
The left side bolt was better but still pretty scary
The engine support bar I built for this job
All the parts I took off about half-way through the tear-down
Getting ready to lower the sub-frame
Catching some of the oil coming out of the axle hole
Loosening the rack & pinion bolts
Draining the tranny oil
The bottom cover; the oil looks nice which is a good sign as to the condition of the tranny internals
Looking at the bottom of the tranny
The cover all nice and clean
Parts diagram of the transmission
Getting ready to lower the engine and transmission
Disconnecting the steering shaft from the rack & pinion
Lowering the engine
View into the top of the engine compartment while lowering the engine and tranny
Finally ready to remove the side cover after 8 hours of labor
The inside of the side cover
The side of the transmission with the solenoids accessible
Another view of the lowered engine/transmission and the side cover removed
The engine way down low
The gasket for the side cover. I had to be very careful so I could re-use it as it costs over $100 for this gasket alone
3 of the 4 solenoids I replaced
The 4th solenoid
The new parts
THIS is the culprit, the EPC (or also called PCS) solenoid
The sway bar link bushings all new and shiny
The sway bar bushing all nice and shiny too
After I flushed the remaining 5L of old transmission oil that remained inside the torque converter

Car ramp
Engine support bar
Impact wrench
Sockets and wrenches
Oxy/Acetylene torch for two rusted bolts
Torx bit
Hook tool

Solenoid kit
12L of transmission fluid




Drives great. I hope it continues like that and I'll NEVER have to do that job again!!!


mel said...

i am so proud of you! i knew you could do it. you are the smarest guy around!

BUT i have to ask why is good kitchen wash cloth in the above pic with oil on it? you owe me a new cloth! which requires a trip to costco, which is impossible to leave with out spending at least's gonna cost you....muwahhhhhh

Anonymous said...

Christian allmost not to belive what you all can and do! I could not sleep anymore with all this parts and places, pictures and hurdels. ... But you did it ! Gratulation. You can take some old fabric home in July to save Melanies kitchen wash cloth. Enjoy canada day and your family . May be with a brand new car... Love Muetti

Anonymous said...

How did you drain fluid from torque converter?

Chris Eigenheer said...

I actually didn't drain the torque converter

Anonymous said...

The text under the last picture is showing like you did. That is why I asked. Thank you.

Anonymous said...

I thought 2005 model year was the start of the Montana SV6's. Kudos to you as my 06 Uplander had a PCS solenoid fail while under warranty thankfully. Still strong now at 226k miles

Unknown said...

Just curious where you got the new stabilizer connectors and bushings? I'm doing a 2001 Montana and am going to need all these as well.

Chris Eigenheer said...

@anotherbri, I got the stabilizer bars/bushings at our local automotive shop called Marshlands Auto Parts. I think they were only like $15 bucks.

Anonymous said...

Hello, Thanks for putting up this information regarding the transmission issues in specific. I have a 2004 Montana and it was shifting very hard. Bought the solenoid kit off eBay and used your notes as reference. I did skip a few steps...I didn't undo the steering shaft knuckle, I left the air bag switches alone, the O2 sensors I left alone which all saved some time. I was able to reuse the gaskets and sway bar bushings although the torsion bar itself had a crack that I did fix by welding. I also used a chain fall and come along to adjust the motor up and down as needed so no elaborate jacking frame was required. The van has 168,000 kilometres on it now and should work well for some time to come. Thank you for writing about the repair course, it worked out well and hopefully my additional input helps others too. Cheers!!

Unknown said...

Chris, Thank you for all the step by step info. You saved me over $2500 in repair cost. My 2008 Uplander is shifting like new. We are repairing our second Van with the same problem. We use these as fleet vans. Thank you so much, God Bless.

Unknown said...


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