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Unread 08-11-2013, 05:50 PM   #1
gearheadnick
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1997 ZJ 
 
Join Date: Mar 2012
Location: Tunkhannock, PA
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How To: change transmission electronics

In my second writeup, I'll show how I replaced all the electronics inside my 42RE transmission in my 1997 Jeep GC 4.0L.

The symptoms I had were at a stop, when I went to go it felt like it was in second gear. I originally thought the trans was slipping, so I bought a filter, gasket, and ATF+4, hoping that adjusting the bands would be the solution. It was not. After searching through posts on this forum I found the correct symptom description, tried putting it in 1st manually, and it engaged 1st like normal, indicating that the governor solenoid or sensor was bad. I found this link:
http://www.cascadetransmissionparts....cekit9697.aspx
and bought it. I tried a price comparison on rockauto.com, and came up with 125 or so for just 2 components. For another 75 bucks I could replace everything in one shot with upgraded stuff. I don't regret that decision.

Anyway, here's the kit I got:



Just like the website said, everything I needed was there. All I was missing was a how to that my Haynes manual nor my FSM had. The FSM had enough pictures of parts that I was confident enough to rip into my trans, and it turns out it isn't too hard to do.



Step one is to get the Jeep up in the air. I drove the front end up on ramps. Jacking the front end up will work also, just be sure to use jackstands also. You will need a pan to catch the waterfall of ATF that is about to come out. Since I just changed the fluid a week ago, my pan had to be clean so I could put the fluid right back in. I also recommend one of those large cookie sheet type of pans you can get at about any parts store, since the ATF coming out will be splashing. A bunch of rags, paper towels, and a can of acetone are good to have also.



These bolts are 13mm. Like I said, I just had the trans open, which is why the pan is so clean. Yours will probably be caked with dirt and whatever fluid(s) yours is leaking. Kerosene is very good for cleaning everything that will be taken apart, with the pan being last since it will be the dirtiest.



Once the pan is off, remove the 3 screws holding the filter in place. They're T25 torx, as is every other torx screw I had to deal with here. I recommend using a torx bit in a 1/4" socket on a 1/4" drive ratchet and a 3" extension. There will be times where the extension is handy and other times you can't use it.



Now at this point you're probably fed up with dripping ATF. I certainly was. I left at this point for about 2 hours hoping it would be done dripping. Well, it didn't stop, but it slowed down enough where it wasn't driving me crazy.



Time to get the governor stuff out. There's 5 11mm bolts and 2 T25 torx screws holding this assembly in place. Unplug the 2 electrical connectors and remove all the fasteners. There's no springs or anything to worry about falling out here. (I must have been holding the camera upside down or something, just flip the image left to right)



This is the assembly. The steel bracket slides off, and the solenoid gets pushed out.



The sensor is held in place with some kind of odd clip. 2 small screwdrivers will wiggle it out.



This is the clip.



After pulling the 2 components out, I cleaned up the aluminum part in kerosene and set it to dry (actually, to cool off, I dried it with a mapp gas torch ). Now it's time to get the accumulator piston and spring out. 5 torx screws holds the plate on.



The plate holds the 3-4 spring that comes with the kit, along with some kind of piston. They should've included new piston seals, but they didn't, so be gentle with it. I found another problem, my spring was broken.



The website said this spring is almost twice as thick as the stock one, but a side to side comparison shows that it's the same size. My conclusion is that a previous owner had this spring replaced.



The piston had very sharp edges, so a very light deburring with a file was in order.
Now comes what I found to be the hardest part. The Lock-Up and Overdrive Solenoid plug is above the accumulator housing, and it goes through the trans case and has a connector that goes wherever. That connector is not fun to disconnect. There is limited room. The connector has 2 tabs that have to be pressed inward. Curse away, but don't get rough with it. Breaking something now will really ruin your day.
Once you get the external connector unhooked, you have to remove the accumulator housing. 3 more torx screws holds that in place. This part does have one spring that will try to get in the way. It's located between the 2 screws that are close together. A small flathead screwdriver will hold it out of the way (it's a weak spring). This is the housing you're removing:




Once the screws are out, hold the spring in its bore and carefully wiggle and pull the housing down. The resistance is from the 2 o-rings on the electrical connector. They've been living in the same position for a long time, and they don't want to move without being persuaded. Once it pops off, the connector is held onto the housing with a torx screw. Remove the screw, let the wires hang, and clean up the housing.



Now for the Lock-Up and Overdrive Solenoid itself.



It's held in place with 3 torx screws (there's certainly a lot of these stupid things). Here's a random shot of new vs old:



There's one more part in the kit, the Output Speed Sensor.



One electrical connection and a 1" socket or wrench and it swaps out real easy. There will be a bit of ATF that comes out, so a small bowl or something will catch it before it drips into the crossmember and onto you.

Now put everything back together in reverse of removal:
Every mating surface gets wiped clean.
Every screw and bolt gets tightened, but not so much that you strip threads. This is all aluminum, so don't overdo it.
The Lock-Up and Overdrive Solenoid has a gasket attached to it, so wipe some new ATF on the gasket before bolting it back.
The plug is bolted back to the accumulator housing, ATF on the o-rings, and wiggled back into place.
Don't forget the weak spring. Or the connection above the trans (like you could ever forget that nightmare plug).
ATF on the accumulator piston, piston into the housing, then the spring, then the plate, making sure to hook the wires into the slot.
The governor sensor and solenoid get ATF on the o-rings before sliding them into the housing.
The governor housing gets a new gasket from the kit. Coat it with ATF.
Before bolting the housing in, plug in the solenoid first (the one with 2 pins). It only goes together one way, and the Lock-Up and Overdrive Solenoid gets in the way with the housing bolted down.
Rotate the solenoid a bit so nothing is pinched.
Connect the sensor plug.
The new filter is put on dry. Make sure to route the wires between the filter and trans in a way that nothing is pinched. I don't think it would hurt to let the wires hang into the pan, but it doesn't seem like a good idea.
Make sure the magnet is in the pan before installing it. (don't ask )
The kit comes with a new pan gasket, and it goes on dry. Do not use any silicone.


I think that's it. If I forgot anything I will try to add it later.


The result: night and day difference. I've had this Jeep for 4 years, and it never drove this nicely. I have no idea how long the spring was broken or which parts were weak, but I don't care. It's all good now.

Any questions, feel free to ask.

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My cylinder head overhaul: http://www.jeepforum.com/forum/f13/cylinder-head-r-r-picture-heavy-1348138/
My transmission overhaul: http://www.jeepforum.com/forum/f13/how-change-transmission-electronics-1560948/
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Unread 08-11-2013, 06:24 PM   #2
coralman
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Good write up, professionally done. Saved in my favorites.
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Links to axle rebuilds, mount replace,a/c box rebuild,ect in history section of my profile page
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Unread 08-11-2013, 06:31 PM   #3
96zedjay
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Very Nice "How to"
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Unread 08-11-2013, 09:12 PM   #4
ZeeJay1997
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hmmm... why did i take my valve body off to do this? Apparently, I didn't notice taking the accumulator housing off would accomplish the same thing. That park rod was tough going back on. Thanks for the writeup.
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Unread 08-12-2013, 07:34 PM   #5
gearheadnick
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When I went to take out the connector end of the lockup solenoid, my first thought was that I'd have to drop the whole valve body. Then I remembered one of the pictures in the FSM showed that the housing came off. I couldn't clearly see that it came off, but I saw 3 screws and went for it.
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My cylinder head overhaul: http://www.jeepforum.com/forum/f13/cylinder-head-r-r-picture-heavy-1348138/
My transmission overhaul: http://www.jeepforum.com/forum/f13/how-change-transmission-electronics-1560948/
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Unread 08-12-2013, 07:52 PM   #6
ZeeJay1997
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I saw the note in your sig. Do this:

copy the link to your writeup
click 'my account' upper rh corner
edit signature
type the text you want to show in sig
highlight the text you just typed
click the globe/link icon in the toolbar
in the box that pops up, right click and hit paste and ok.

that ought to do it
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Unread 08-12-2013, 08:26 PM   #7
newfieZJ
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Nice , great pics
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Unread 08-12-2013, 09:25 PM   #8
StPaul59
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Ive heard people are having problems with cascade sensors.
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Unread 08-13-2013, 04:00 AM   #9
gearheadnick
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Thanks zeejay, I'll try that tonight
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My cylinder head overhaul: http://www.jeepforum.com/forum/f13/cylinder-head-r-r-picture-heavy-1348138/
My transmission overhaul: http://www.jeepforum.com/forum/f13/how-change-transmission-electronics-1560948/
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Unread 10-28-2013, 03:17 PM   #10
Gibby913
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Awesome write up......I'm going to be doing this in the spring......thanks for pointing out the cascade kit....great find

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Unread 10-28-2013, 09:31 PM   #11
kahl452
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Thank you for this. getting to the over drive and lock up solenoid is a pain!
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Unread 11-08-2013, 04:02 AM   #12
gearheadnick
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I'm glad I could help some people out with this writeup. To update, my trans is still running perfect. I will be replacing the 3-4 spring plate sometime after winter. The wear that it has makes me think that the spring will wear out faster due to not having a flat surface to ride on. Of course I won't be swapping it until it's time for a fluid change.
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My cylinder head overhaul: http://www.jeepforum.com/forum/f13/cylinder-head-r-r-picture-heavy-1348138/
My transmission overhaul: http://www.jeepforum.com/forum/f13/how-change-transmission-electronics-1560948/
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Unread 11-08-2013, 11:46 PM   #13
kahl452
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I finally got around to fixing my jeep today. I bought the kit a week ago and purchased 6 quarts of transmission fluid. It took me about 6 hours to complete the whole process. It's really nice to be able to actually go from a dead stop instead of having my vehicle start in second gear all the time. Your write up helped me a ton. Thanks again!
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Unread 11-09-2013, 06:14 AM   #14
Gibby913
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My jeep has really delayed shifting points for 2nd and 3rd gear, she also hates downshifting.... I've tried everything from a fluid and filter change to adjusting the tv cable.....no difference. To get her to downshift I just pop it in neutral and the back into drive. I found no signs of tranny damage when changing the filter.

Gear do you think this would fix my problem?
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Unread 11-09-2013, 09:41 AM   #15
gearheadnick
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It couldn't hurt. Your jeep is as old as mine, but I have no idea as to the condition of your trans. I had no signs of damage either, but you can't see the 3-4 spring unless you take off the retainer plate. All the electronics I changed control how and when the trans changes gears. Since you haven't found metal shavings or broken parts laying in the pan, the kit I bought is a logical starting point. Worst case scenario, you'll make sure those parts aren't the problem, and having electronics submerged in hot liquid isn't the best way to prolong their life.
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My cylinder head overhaul: http://www.jeepforum.com/forum/f13/cylinder-head-r-r-picture-heavy-1348138/
My transmission overhaul: http://www.jeepforum.com/forum/f13/how-change-transmission-electronics-1560948/
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