Jeep Wrangler automatic transmission fluid and filter change

TerryMason

Administrator
Staff member
My 2005 Jeep Wrangler has about 66,000 miles on it at the time of this writing, far past the recommended time to change the automatic transmission fluid and filter. The 4-Speed 42RLE automatic transmission that came on my model year is not known as a very reliable transmission, since it's prone to early failures. You can get a lot of extra life just by changing the fluid in your 42RLE transmission. It turns out that I didn't need to put off changing it, because it's a pretty straight forward process that can be done In about 2 to 3 hours for your first time.

The overall process is pretty straight forward:
1. Remove the transmission skid plate.
2. Remove all the bolts around the transmission pan and drop the pan, trying not to get ATF everywhere
3. Replace the transmission filter with a new one
4. Bolt the pan back on
5. Fill the transmission back up with ATF


Parts needed
Transmission filter kit - $31.48 (Advanced Auto Parts)
Castrol ATF+4 (6 quarts) - $35.94 (Advanced Auto Parts)


So, why change the ATF in your Wrangler?
The primary cause for automatic transmission failure is due to heat. Most ATF is designed to run at 175 degrees F. At this temperature most ATF will last at least 100,000 miles - the problem is that for every increase of 20 degrees above 175 the life span of the ATF is cut in half. That means that at 195 F the ATF will last 50,000 - at 215 F (which is commonly seen in many transmissions) the life span is only 25,000 miles.

When the transmission fluid in your Jeep goes bad, it will turn a brownish color, and give off the smell of burnt toast. The only rememdy for burnt or bad transmission fluid is to change it out (there are no additives that can restore bad transmission fluid).
 
Last edited:

Contents of the Jeep transmission filter kit

This is what came in my Pro King FK-361 standard Wrangler transmission filter kit. A replacement gasket, a new filter, and an O-ring.

IMG_1260-jeep-wrangler-automatic-transmission.JPG
 
Last edited:
Removing the transmission skid plate

Step one is to remove the four bolts that hold the Jeep's transmission skid plate on. There are two larger bolts that connect to the frame, and two smaller bolts towards the rear.

As would be my luck, the driver side front bolt gave me some real problems. There appears to be a nut inside the frame itself that spun loose. The end result being that I couldn't get the skid plate off. I ended up using a long pry bar to bend the skid plate down, then I rotated the whole thing out of the way.

IMG_1269-jeep-wrangler-automatic-transmission.JPG

IMG_1271-jeep-wrangler-automatic-transmission.JPG
 
Last edited:

Removing the bolts from the transmission pan

Once the Wrangler's skid plate is removed, you can begin taking out the bolts that hold on the transmission pan. I left one bolt in each corner, and took all the rest out.

IMG_1272-jeep-wrangler-automatic-transmission.JPG
 
Last edited:
Removing the Jeep transmission pan

Carefully position your oil pan under the Jeep and remove two of four remaining bolts on one side of the Jeep. Chances are that the transmission pan will simply stay put - held on by the gasket, but be ready for a torrent of transmission fluid.

IMG_1275-jeep-wrangler-automatic-transmission.JPG

Once I was down to two bolts, I had to beat on the pan with a rubber hammer, then carefully pry it open with a screwdriver (don't gouge the metal!). The slower you go here the better. Once you have enough of the fluid out, remove the pan.

IMG_1278-jeep-wrangler-automatic-transmission.JPG

IMG_1281-jeep-wrangler-automatic-transmission.JPG
 
Last edited:

Removing the used Wrangler transmission filter

Now that the Wrangler's transmission pan is off, you can remove the filter. The transmission filter is held on by two small torx bolts. If you don't have any torx, you can usually make due with a hex key / allen key.

IMG_1283-jeep-wrangler-automatic-transmission.JPG

IMG_1294-jeep-wrangler-automatic-transmission.JPG
 
Last edited:
Installing the new transmission filter

Install the new Jeep automatic transmission filter, making sure to use the included rubber O-ring.

IMG_1291-jeep-wrangler-automatic-transmission.JPG

IMG_1297-jeep-wrangler-automatic-transmission.JPG
 
Last edited:

Filling the Jeep with ATF+4 and testing the transmission

Now reinstall the transmission pan and the skid plate (don't forget the magnet that goes in the transmission pan - you have to take it from the old one). I then poured my used ATF into some containers - it turns out that I took out 5.5 quarts of fluid, so I put in 5.5 quarts of new ATF+4 as a starting point.

IMG_1298-jeep-wrangler-automatic-transmission.JPG

IMG_1300-jeep-wrangler-automatic-transmission.JPG

Then start the engine, chock the wheels, and shift the Jeep's transmission into neutral - this will cause the transmission to pump fluid. Let your Jeep warm up for 10 minutes or so, then while it's running, shift the transmission into park. With the Jeep still running, check the transmission fluid level. Top it off if you're low, and you're done!


 
Last edited:
Wow! I didn't know that doing an automatic transmission fluid replacement
would be this easy. I'll probably change the fluid next time by myself.
 
Last edited by a moderator:

I got a filter from Auto Zone, but it looks totally different. Instead of having a plastic housing, it's just a thin fabric filter. Oh, and no O ring. Am I missing something or is that the difference between the $7 and the $31 filters?
 

Re: Removing the transmission skid plate

Step one is to remove the four bolts that hold the Jeep’s transmission skid plate on. There are two larger bolts that connect to the frame, and two smaller bolts towards the rear.

As would be my luck, the driver side front bolt game me some real problems. There appears to be a nut inside the frame itself that spun loose. The end result being that I couldn’t get the skid plate off. I ended up using a long pry bar to bend the skid plate down, then I rotated the whole thing out of the way.

I had the same problem, there is no way to keep the head of the bolt from spinning with a ratchet. A high speed impact gun did the trick for me.
 
Re: Removing the transmission skid plate

I had the same problem, there is no way to keep the head of the bolt from spinning with a ratchet. A high speed impact gun did the trick for me.


After you were done, how did you get the skid plate back on and anchored, since the nut that held it had broken loose?
 

Re: Removing the transmission skid plate

After you were done, how did you get the skid plate back on and anchored, since the nut that held it had broken loose?


I had to first replace the bolt on the passenger side loose with just a few threads on and hit the driver side with an impact gun (electric DeWalt). There is no bracket to hold the head of the bolt so you have to have the weight of the skid plate to hold it, and the speed of the the impact gun will draw it up tight, that is with the rear bolts loose. That turns out to be the easy part! I drove up the road the next day and the trans popped out of gear on a main road! Luckly I coasted into a driveway and after a few seconds it worked again and I made it home very distraught as I have only made 1 payment so far! Turns out the owners manual says it MUST be in park to check the level, it looked full to me after 4 quarts in Park, and the dip stick says Neutral... nowhere does it say with the engine running. Well thanks to this article I warmed it up in Neutral, put it in park and checked the level, while the engine was idle. At 1st it didn't even register on the dipstick. Nearly 2 quarts later it registered and I took the dreaded turn today and all is good. The turn is off camber, I guess the pick up didn't pick up enough the first time. All of the books I have say the capacity is 4 quarts... more like 6 when removing the pan and refilling and replacing the filter! I hope to keep my LJ forever but I think I'll replace the transmission before I change the fluid again!
 
Re: Removing the transmission skid plate

Hey TerryMason...I was thinking of changing the trans oil and filter and I have read other threads if you remove the skid plate you have to put a jack under the transmission, as it tends to drop some. I have a 2005 Jeep Wrangler Unlimited that looks identical to yours underneath. I was curious if this is something you had to do or did you just remove the skid plate and go at it??? thanks
 

The stock skid plate is not attached to the auto transmission. You remove the front part of the plate to get to the pan that holds the ATF. I would show you a pic of my '06 Unlimited, but I had made a different plate to prevent it from rubbing the drive shaft. Something for you to be aware of if you have a lift (mine was 4") - the factory plate has a piece toward its front that connects to the driver's side of the frame. That piece will rub the drive shaft if you offroad/ disconnect the sway bar. I had over 2 inches that my drive shaft dropped farther once I removed that piece of the plate!!!
 
Here are pics I found of my old plate when I was removing it and the mark where it was rubbing the drive shaft. The pic shows how far down I had to drop the plate before it didn't touch the shaft!
 

Attachments

  • image-2135663171.jpg
    image-2135663171.jpg
    448.3 KB · Views: 1,842
  • image-2591376309.jpg
    image-2591376309.jpg
    412.4 KB · Views: 1,086

Re: Removing the transmission skid plate

I was curious if this is something you had to do or did you just remove the skid plate and go at it??? thanks

Trail Rated is right, you can remove the engine skid plate (the T shaped one, towards the front of the Jeep) without a problem. It's the larger transmission skid plate that you can't remove without supporting the transmission.
 

So my son's '01 has been running rough, trying to stall at stops and lurching/bucking at low speeds. After reading through this thread we changed the transmission fluid and filter last night. I was THRILLED when we drove it and all the rough running/driving had subsided! Thanks for the write-up!
 
Back
Top