So I have a 2004 Jeep Wrangler unlimited 4.0 with the 4 speed auto 42RLE with 160k miles and I am wanting to change my tranny fluid as it probably hasn’t been changed in a while I know how to change the fluid once I can get to the transmission oil pan but there is this giant skid plate that is bolted to the frame right under it. So can I just unbolt this plate or do I need to do something els. And any tips for changing the fluid? Thanks
How do I change 42RLE transmission fluid?
- Thread starter Tzerambo
- Start date
Remove the transmission skid, that should get you enough room to remove the pan without removing the belly skid. You don't need to support anything unless you remove the belly skid.
MountaineerTom
LJ Enthusiast, Retired USAF Weapons Loader
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I think there is one bolt that is supposed to have some RTV put on it when you reassemble. It’s mentioned in the service manual, which is available on this site. I don’t recall which bolt of the top of my head though.
Dropping the pan only allows you to drain/replace about 1/3 of the ATF inside the transmission, it doesn't drain all of the ATF inside the transmission, its torque converter, and its cooling system. I'd drop the pan to replace the filter, then add 4-5 quarts to of fresh ATF+4 to top it off, then flush the old ATF out into a bucket until it turns clear bright red.
Flushing is done by disconnecting the transmission cooler output line connector from the radiator and (while the engine is running) using the transmission pump to pump the old ATF out into a 5 gallon bucket while you add fresh ATF+4 (only!!!) from the top via the transmission's dipstick tube after inserting a small funnel into it. Stop flushing once the ATF turns bright/clear red. Then once the cooler line is reconnected to the radiator, top off the transmission with enough ATF+4 to get it to the full mark. Only measure the ATF+4 level with the transmission dipstick while the engine is running so you can get an accurate ATF level.
Flushing is done by disconnecting the transmission cooler output line connector from the radiator and (while the engine is running) using the transmission pump to pump the old ATF out into a 5 gallon bucket while you add fresh ATF+4 (only!!!) from the top via the transmission's dipstick tube after inserting a small funnel into it. Stop flushing once the ATF turns bright/clear red. Then once the cooler line is reconnected to the radiator, top off the transmission with enough ATF+4 to get it to the full mark. Only measure the ATF+4 level with the transmission dipstick while the engine is running so you can get an accurate ATF level.
Pay no attention to the clueless types who repeat rumors that changing the ATF in an automatic transmission with a lot of miles on it will wreck it. It's never a bad idea to change the ATF. If a transmission fails after its ATF was changed it was about to fail anyway. Keep in mind that too many (clueless) people wait until the transmission is acting wonky before they ever change the ATF.
Well it might just be me thinking it’s acting up or not but I just bought it a few months ago and I’m sure the fluid hasn’t been changed in a while so this is one of the things on my to do list and I was planning on doing it anyway. But I have to ask you there is two plates under my Jeep I have this big skid plate under the back of transmission and I see this all the time in videos and there’s this smaller plate that’s sitting under my transmission pan how do I remove this smaller plate as I haven’t seen anyone ever do this on the internet?
The small skid plate is attached to the frame rail by 2 bolts, and the larger skid plate by 2 bolts. n my 06, the bolts are metric, but IIRC, they are SAE on earlier models.
PneumaticNomad
New Member
Hey JB, pardon the ignorance but, would disconnecting the TCO line from the radiator in order to get enough of the ATF out before pulling the pan for the filter be a viable option or will this just drain the torque converter and cooling system 1st, posing a risk to the tranny? I'm looking for ways to mitigate the fluid mess that happens when pulling the pan for a filter swap, with a tranny full of fluid.
That'd work fine but there's just not much that can be done to make it a non-messy job. The pan is going to be full no matter what. Spread out a whole bunch of newspaper etc. under the container for the ATF to at least help contain the mess.
This wont work, pulling the lines wont drain anything from the pan to help with the mess. The return line is above the pan, it can't pull fluid and you can't draw fluid out of the pump. If you pull the line and then run the engine to drain the fluid without adding more you risk running the transmission dry which is not a good idea in my opinion. If there was a simple way to just run it dry and then add new fluid somebody would have found it by now. Great to think about alternatives but this isn't going to do much for you.
PneumaticNomad
New Member
Thanks for the response, JB - in that case, I'd rather not risk running the tranny dry and just brace myself for the mess. So just that I have it straight:
1. Remove pan cover, drain the xfer case area.
2. Swap filters.
3. Clean mating surfaces on both, cover and case, ATV/gasket & tighten.
4. Fill with 4 or 5qts of ATF+4, check dipstick with vehicle off.
5. Start engine, cycle through the gears, re-check ATF level, top off.
6. Pull the cooler output line and drain/fill til its red.
Last question, should I have to cycle through gears to get a proper measurement, and can the vehicle just be in Neutral, or do I need to cycle the gears while pumping/draining old ATF?
I appreciate your patience; just crossing my i's and dotting my t's.
Sounds good here are two things I'd add... leave the two rear outer-most bolts that hold the transmission pan loosely threaded in so you can control the pan and lower the pan from the front so it drains with good control. Then after getting the pan sealed and in place, I'd go ahead and add 7 quarts before starting the engine. Then start the engine, shift through the gears, then with it in Park bring it up to the full mark. It's better to be slightly overfilled than slightly underfilled.
PneumaticNomad
New Member
Sorry for the huge lag in getting back - last 2 months have been quite the snag. Thanks again for all your help & guidance, JB!
PneumaticNomad
New Member
So just to be clear, once the filter's been swapped and the pan is sealed back up, the output line I'd be using to flush the torque converter/cooling system is the one on the bottom/driver's side of the radiator, is this correct? I would assume it's not the return line as this is what feeds the tranny new fluid. Pardon the dumb question, Just making sure I don't fudge this up.
Will add my experience from changing fluid in 42rle in JK:
When oil pan came off, all 8 quarts came out. I was roaming internet for days trying to find explanation, since my experience contradicted everything that is written in every guide. Dont know what, dont know how, all i know is that 8 quarts came out, and 8 quarts went back in.
When oil pan came off, all 8 quarts came out. I was roaming internet for days trying to find explanation, since my experience contradicted everything that is written in every guide. Dont know what, dont know how, all i know is that 8 quarts came out, and 8 quarts went back in.
PneumaticNomad
New Member
Well, while I do appreciate you sharing that experience, I'm left to trust that TJs work differently than JKs and don't bleed out through the pan entirely. Thanks for the info on that though, EBloc.
PneumaticNomad
New Member
Correction: The tranny fluid output is on the bottom passenger side, return is on the driver side - or do I have that backwards?
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