Replacing AW4 Transmission...FML

[W00GYB00GY]

So I've been putting it off for about a month now, but my I'm 99.9% sure my transmission needs to be replaced. I've done just about everything except check the solenoids because that's out of my difficulty level although I plan on bringing it into the shop to have them tested, I just know its a pain in the ass cause they have to drop the pan and it isn't easy/cheap.

Here is the thread I posted a while ago about my troubles with the AW4;
http://www.naxja.org/forum/showthread.php?t=1076998

If I end up buying a used transmission I know it will be pricey, but I found some online for $251.00 shipped, and then to have someone install it will be another $350, but this is the one I plan on buying if the solenoid doesn't end up being the problem;
http://info.automotix.net/usedtrans...s=2010726c957839b68ebab04034e3a183&seq_num=11

It's the 2nd one listed on that page. What do you guys think?

 

[bigalpha]

Checking the solenoids does not require you to drop the pan. You can test them at the TCM and at the connector at the firewall.

 

[W00GYB00GY]

I don't think its the solenoids cause yesterday and today it shifted perfectly fine, no problems whatsoever...

I'm starting to think it's not the solenoid because if it was wouldn't it just not work at all rather then sometimes here and there?

Also, I've changed it twice in the last 3,000 miles. I bought it with 100,000 miles on it, now it has 106,000, The guy before me didn't change it at all I believe...

What do you guys think about this?

 

[bigalpha]

Could be an intermediate wiring problem, including a ground issue.

 

[kastein]

agreed. You can check the solenoids with a 5 dollar meter - they should be 11-15 ohms from ground to the solenoid wire with the TCU connector unplugged. Test them while it's driving normally, then while it is acting up. If there is no difference it could be a hydraulic/mechanical failure but if there is a difference or they are out of spec even when it is driving normally it is likely that it's a solenoid failure.

 

[W00GYB00GY]

Where exactly do I test for the solenoids? Inside my jeep where the wires connect to the Transmission Control Module, or under the hood by the engine?

My transmission would constantly slip and I couldn't get into OD for about 2 weeks, (I had to drive in "3") then all the sudden yesterday it worked perfectly fine...so weird! I really need to figure this out!

Thanks!!!

 

[bigalpha]

You can test the solenoids at both locations.

 

[W00GYB00GY]

If I were to test them near the Transmission control module inside I would just stick my meter inside the wires and obviously the ground to a ground and thats all I do?

 

[kastein]

yes - should be easy, just poke the appropriate pin in the connector with the meter probe and hold the other to a solid ground.

 

[W00GYB00GY]

yes - should be easy, just poke the appropriate pin in the connector with the meter probe and hold the other to a solid ground.

How do I know which is the appropriate pin in the connector? Thanks!!!

 

[kastein]

Factory service manual should have that info - here's the data from my 96 FSM:
solenoid 1: cavity C16 in connector, wire color dark blue / white
solenoid 2: cavity C15 in connector, wire color violet / white
solenoid 3: cavity C14 in connector, wire color white / black

solenoid 3 is the torque converter lockup solenoid.

 

[W00GYB00GY]

Ok thanks I'll have to try that out!

 

[W00GYB00GY]

Ok so I tested the Solenoids with my multimeter set on DCV 20; Keys in the ignition just the power on... Everything came back 0.00... I'm 100% positive my ground was good and I tried several different grounds.

I checked my battery and a couple other things to see if it multimeter was broken, but it is working perfectly fine...I'm not sure if I did something wrong can you guys help me out?

 

[kastein]

You need to use the 200 ohm scale, not the volt scale - you're measuring resistance not voltage. Key position doesn't matter in this case since the solenoids are unplugged from the TCU (as they should be.)

 

[Tecknique2007]

Could be an intermediate wiring problem, including a ground issue.

YES! Look at the wiring, including the ground. After I had dropped my, what turned out to be perfectly fine AW4 with 240k on it, complete with fresh solenoids, I found I had a loose ground for the TCM. Causing the intermittent shifting issues that I perceived as some sort of physical shifting problem. While I did end up with a tranny with alot less miles out of the ordeal, it was completely unnecessary. Unless you really want to replace the transmission, thoroughly check the wiring.

 

[kastein]

Good point. I did experience intermittent shifting issues on my 96 at one point that I traced to a loose ground connection on the left inner fender, between the ECU, air filter, and brake master cylinder. If you have intermittent hvac blower operation at the same time it is definitely this ground. Oversize tires frequently rub on the inner fender and loosen the screw by wallowing out the hole it goes into. I solved the problem by welding a small machine screw headfirst to the fender as a stud and then used a nut to hold the ground down instead of the original self tapping screw.

 

[O-Gauge Steamer]

^^Funny you should point out this method for that ground. I did a similar thing for the main body ground next to the battery. Welded in a 3/8" bolt to the inner fender to take the ground from the battery. Then I went around the rig and redid all of the grounds.

If you do not have access to a welder, scrape the paint clean, drill the hole to take the machine screw and use external tooth star lock washers under the head of the new grounding bolt and the nut you use to hold it to the sheet metal. This will make a grounding stud, then carefully add paint. The external tooth washers will bite into the sheet metal giving a better connection. Be sure to keep the paint off of the threads and the top of the nut.

 

[W00GYB00GY]

So I just used the 200 ohm scale and all 3 solenoids came back at 2.6...


I don't understand whats going on. I thought they were supposed to be between 11-16?

 

[bigalpha]

Which ground are you using? Did you test the ground on the TCM connector and see if it was good?

Also, you can test those three solenoids at the grey connector at the passenger side of the firewall.

 

[W00GYB00GY]

For the ground I had placed the black wire on one of my door hinges (metal) then I also put it on a metal piece in the dash.