To change transmission fluid or not to change?

OffroadOran · Sep 25, 2016

Hi all,

I have an 04 at 103k with original trans and was thinking about doing a simple fluid and filter swap. I bought the vehicle with 74k miles and I don't know when it was done last (if ever). I heard some people were concerned about doing a transmission fluid change on higher mileage transmissions due to it causing problems and wanted to see what you all thought. I currently have no known transmission issues, and would be doing this to keep the tranny is good health.

Lost_Mind · Sep 25, 2016

Healthy fluid = healthy transmission IMO

tymaoaretae · Sep 25, 2016

I'd change it. It's not difficult and changing it won't hurt anything. I changed mine around 160k miles. The idea that old fluid is helping things continue working when they otherwise wouldn't be is pretty much nonsense, just like the idea that switching to synthetic oil will cause problems on old or higher mileage engines. The only possible grain of truth is that doing a reverse flush with a machine could cause issues. But that isn't nearly the same thing as a fluid and filter change. If you're just dropping the pan you're really only changing about half the fluid anyway.

cNagy · Sep 25, 2016

Change it

OffroadOran · Sep 25, 2016

Lost_Mind said:
Healthy fluid = healthy transmission IMO

tymaoaretae said:
I'd change it. It's not difficult and changing it won't hurt anything. I changed mine around 160k miles. The idea that old fluid is helping things continue working when they otherwise wouldn't be is pretty much nonsense, just like the idea that switching to synthetic oil will cause problems on old or higher mileage engines. The only possible grain of truth is that doing a reverse flush with a machine could cause issues. But that isn't nearly the same thing as a fluid and filter change. If you're just dropping the pan you're really only changing about half the fluid anyway.

I would definitely not be doing a flush, just a swap. I'd want to drop the pan and put in some new ATF and a new filter....nothing too stressful for it I'd think. Alright well it sounds like a decent idea then ill probably be going ahead with it. I had a mechanic friend who never changed the fluid and filter in his vehicles because he swore that it caused more harm than good, along with the fact new vehicles "needed no tranny service", so I took his advice but I always thought he may have been wrong about that.

Anyways, this would be my first time doing this and I was going to use the guide on the bottom of this page http://wjjeeps.com/service/transmission.htm . Do I have to put the vehicle on jack stands, or can I just crawl under there like I do for oil changes? Also does anyone know a better guide for this with pictures or a video? I know its fairly easy and it seems easy enough, but having that visual helps me a lot.

tymaoaretae · Sep 25, 2016

I have a friend who has a Saturn ion with one of those "sealed for life" transmissions. Started really acting up around only 40k miles. It ended up needing a fluid change, which solved the issue completely.

Anyways, if you can get yourself and a drain pan under the jeep, then you don't need to put it on jack stands. Dropping the pan can be really messy if you tip it pretty much at all while you're taking it off. Might be easier with jack stands if it's tight.

BlueJc · Sep 25, 2016

I Changed my fluid 3 times. I dropping the pan then refilled to correct level. I then ran the jeep for a few weeks then dropped the pan again and repeated the process further diluting the old fluid with new. I cleaned the magnet, replaced the filter and pan seal. Job done....

This is how I done the job:
http://www.jeepforum.com/forum/f310.../forum/f310/transmission-fluid-change-my-2002-2-7-crd-wg-wj-3711577/?highlight=

OffroadOran · Sep 25, 2016

BlueJc said:
I Changed my fluid 3 times. I dropping the pan then refilled to correct level. I then ran the jeep for a few weeks then dropped the pan again and repeated the process further diluting the old fluid with new. I cleaned the magnet, replaced the filter and pan seal. Job done....

This is how I done the job:
http://www.jeepforum.com/forum/f310.../forum/f310/transmission-fluid-change-my-2002-2-7-crd-wg-wj-3711577/?highlight=

oh okay that looks easy enough! I'm guessing the only differences are the type of filter and gasket right? Otherwise same procedure other than the fact I don't have a drain port correct?

BlueJc · Sep 25, 2016

OffroadOran said:
oh okay that looks easy enough! I'm guessing the only differences are the type of filter and gasket right? Otherwise same procedure other than the fact I don't have a drain port correct?

Mine is a diesel so dunno what is involved. I would guess the procedure would be much the same. I'm sure someone with the petrol variant will pipe up soon. My engine and transmission are mercedes units IIRC :wink2:

three_jeeps · Sep 26, 2016

OffroadOran said:
I would definitely not be doing a flush, just a swap. I'd want to drop the pan and put in some new ATF and a new filter....nothing too stressful for it I'd think. Alright well it sounds like a decent idea then ill probably be going ahead with it. I had a mechanic friend who never changed the fluid and filter in his vehicles because he swore that it caused more harm than good, along with the fact new vehicles "needed no tranny service", so I took his advice but I always thought he may have been wrong about that.
.

No offense, but your mechanic friend made a very stupid statement. The fluids (chemically) break down with use. temperature cycling plus dirt cause them to change their compressability properties. The fluid carries particulates to other parts of the tranny over time, even though they are being filtered.
Go by the book interval, or maybe 10-20% longer. do a complete drain, use good quality filters, and, IMO, use Mopar fluids.

Also, I'd change the differential and transfer case fluids as well. IIRC, the SM calls out a 30K miles service interval.
Good luck
J

OffroadOran · Sep 26, 2016

three_jeeps said:
No offense, but your mechanic friend made a very stupid statement. The fluids (chemically) break down with use. temperature cycling plus dirt cause them to change their compressability properties. The fluid carries particulates to other parts of the tranny over time, even though they are being filtered.
Go by the book interval, or maybe 10-20% longer. do a complete drain, use good quality filters, and, IMO, use Mopar fluids.

Also, I'd change the differential and transfer case fluids as well. IIRC, the SM calls out a 30K miles service interval.
Good luck
J

Alright I'll probably get that done soon . Also I did change both the T case and differential fluids less than 30k miles so those are all set for the time being.

Sprung99GC · Sep 27, 2016

Mine has had a pan drop and filter change every 30k along with Xfer case and axle service. I have records of every one of them from the original owner and have continued with it. Trans fluid looks like new and it shifts great with 160,000 miles on the clock.
When in doubt change it!

OffroadOran · Oct 4, 2016

alright so I got my fluid, filter, and felpro gasket. Ill drop the pan and replace all those. Do I need to change the fluid in 3000 miles again? Also, If I need to replace the fluid in 3000 miles do i need to replace the filter I just bought as well?

steve_80 · Oct 4, 2016

3000 miles? why so early? or did you mean 30,000 miles?

OffroadOran · Oct 4, 2016

steve_80 said:
3000 miles? why so early? or did you mean 30,000 miles?

I said 3000 because I thought that if youre only replacing 1/2 the fluid by dropping the pan you need to do it again after 3000 miles so that you have all new fluid right?? or am i thinking of that wrong? Look at what BlueJc said in his comment in this thread, he replaced it 3 times. Maybe I got 3 replacement times and 3000 miles mixed up.

cNagy · Oct 4, 2016

OffroadOran said:
I said 3000 because I thought that if youre only replacing 1/2 the fluid by dropping the pan you need to do it again after 3000 miles so that you have all new fluid right?? or am i thinking of that wrong? Look at what BlueJc said in his comment in this thread, he replaced it 3 times. Maybe I got 3 replacement times and 3000 miles mixed up.

No you are right. But honestly, that's only if you really want to have all new fluid. If you do not have any transmission issues, and your fluid is still good color, a simple fluid/filter change will be fine. But if your fluid is starting to get dark or smells burnt, then it would be a good idea to do multiple changes or go the route in which you "flush" with the cooler lines at the radiator.

steve_80 · Oct 4, 2016

ah ok, i guess it makes sense... i do that with my PS fluid

If you're going to do that, make it easier and get the Dorman Transmission pan with a drain bolt.

OffroadOran · Oct 4, 2016

cNagy said:
No you are right. But honestly, that's only if you really want to have all new fluid. If you do not have any transmission issues, and your fluid is still good color, a simple fluid/filter change will be fine. But if your fluid is starting to get dark or smells burnt, then it would be a good idea to do multiple changes or go the route in which you "flush" with the cooler lines at the radiator.

steve_80 said:
ah ok, i guess it makes sense... i do that with my PS fluid

If you're going to do that, make it easier and get the Dorman Transmission pan with a drain bolt.

Last time I checked the fluid the color looked okay but ill check it again before I do this so that I can determine whether to just leave it or not. And depending on the price, I may just get the new tranny pan with the bolt anyways cause im not excited to have 5 quarts of fluid pour out of every edge of the pan if I ever wanna do this again lol.

leadsled jeep · Oct 4, 2016

Bought my '02 Overland with 107k. Changed tranny fluid about 115k. Swapped two new filters and installed Amsoil. Used engine to pump out old with one cooler line disconnected while I filled from top and pan re installed. About 1-2 qts pumped out at a time. Easy to see when all. Ew fluid is in system as fluid coming out of hose suddenly gets new looking!

She's about to turn 190k. I changed just the pan and filters over the summer.

Vonderbal! Not had any tranny issues at all. Knock on wood.

OffroadOran · Oct 6, 2016

My tranny fluid from the dipstick looks like this, hows it looking? I gotta do my brakes first then Ill be able to change the fluid and filter (hopefully, getting both done tomorrow)

To change transmission fluid or not to change?

OffroadOran

Lost_Mind

tymaoaretae

cNagy

OffroadOran

tymaoaretae

BlueJc

OffroadOran

BlueJc

three_jeeps

OffroadOran

Sprung99GC

OffroadOran

steve_80

OffroadOran

cNagy

steve_80

OffroadOran

leadsled jeep

OffroadOran

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