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Maintenance Concern, HELP!

92westshady

NAXJA Forum User
Location
Newark, DE
Okay so I am a bit compulsive about maintenance. I change my oil and filter and rotate my tires every three thousand miles, my wipers every 4 months, never let my gas gauge get below a quarter of a tank and always top off my wiper fluid before it runs out...you get the idea.

So I was reading that a lot of people don't think you should change the transmission fluid often or ever because it can loosen up dirt and cause problems or something like that. Well I changed the my transmission and transfer case fluids last year when I got my Jeep about 15K miles ago and my questions is, aside form it maybe being unnecessary is there any hard evidence to show that it is bad or harmful to change the your transmission and transfer case fluid once a year?

I would also appreciate it if someone could refresh me on the type of fluid the AW4 takes, Dexron II or Dexron III?
 
Change away!! The only concern is usually if the fluid hasn't been changed in a long time, it can loosen up crud and send it floating around inside of your transmission. It seems like you don't have this problem so I'd change it as often as you like. The more the better.

Mine manual says Dex II but I think Dex III is just an improvement to Dex II.
 
Change it in the normal way, but don't have one of those power flush jobs. Tranny shops discourage this, because it will loosen up all sorts of stuff that's best left alone. I wouldn't do the flush except as a last resort for a dying box. I would also not bother to replace the filter (which in the case of the AW4 is just a large metal screen), if the fluid is clean looking and not cooked. It's almost certain not to need replacement, and there are a couple of magnets in the pan to catch filings anyway.
 
Since you can't really find Dexron II anywhere (just Dexron II/III or Dexron IIE/III) go ahead and use Dexron III. It's backwards compatible anyhow.

DO NOT use Chrysler ATF +3/+4 in the AW4 - it really doesn't like it! Even the ChryCo techs seem to space this out on occasion - the AW4 is not a Chrysler slushbox - it was designed by Toyota (and is used on Pickup, RWD Van, Celica, Supra, and some RWD Lexus models.)

Also, reports from the field seem to indicate that switching to synthetic in the AW4 is likewise a bad idea - since synthetic fluids tend to lubricate better, I'd guess the common problem is clutch chatter and slippage. So, don't use it.

You can flush the AW4 using any commercially available cleaner (I like Berryman B-12 "Chemtool,") but reports from the field on the "power flush" are consistently negative.

As far as the "filter" goes - it isn't, really. It's just a screen strainer that catches any large bits - the first time you change the AW4 fluid, I'd just clean the strainer and the magnet, and put them back. You just need a pan gasket for this - FelPro makes one, but I don't recall the number offhand. Don't get the filter kit, you don't need it.

If you worry about things floating around in your transmission, you may want to add a remote filter setup. I'm sure it's doable, it's just on my list of things I haven't done yet. I certainly feel better if there is a true filter in line, and it's easier to inspect (just cut open the filter and eyeball the media.)

Short form -
Use Dexron II/III or Dexron IIE/III fluid, not synthetic!
Don't use ATF +3 or ATF +4
Don't get a filter - just clean the strainer and magnet
Don't power flush.

The AW4 actually will stand up to a good deal of abuse - I'd hate to tell you what I've put mine through - and taking care of it is quite simple. The only way I can really see to blow one up would be to use the wrong fluid, or use it until it looks like engine oil...
 
Okay thanks for the advice.

I am gonna go with Pennzoil Dexron-III Mercon, just realized after I asked what the right fluid was that I have half a case in the garage from last year's change.

The trans filter/screen and gasket change was a time consuming PITA last year so I think I am just gonna drain what I can from the plug this year and fill'er up with fresh fluid. Maybe I will wash the screen and swap the gasket next year.

Thanks again for the info.
 
Remember that when you drain transmission it leaves a couple quarts behind in the torque convertor. So, frequent drains and refill will help get all of it out better than one drain/change every couple years. I don't like power flushing.
 
I'm an XJ newb, so go with the advice of the experts if they think this is a bad idea.

To get all the fluid, a technique people use (in other transmissions), after changing the fluid/filter in the pan, they disconnect the return hose from the cooler and run it to a bucket. You start the motor and let it run at idle, monitor the fluid as it is pumped out into the bucket as you add fresh fluid. When you hit the amount of fluid that would be trapped internally (total fluid capacity - fluid you added to the pan, during the pan change) they shut down the motor, reconnect everything and then make sure they have the fluid level right. This technique is NOT without its risks, but a lot of people have done it without problem.

Most modern auto trans have a thermostat, that will redirect a portion of return fluid back to the pan if the fluid is cool. So even the above technique, there will be some fluid mixing and you won't get all the old fluid out, but a lot more than just changing whats in the pan.

What I do with my Chrysler A-604 in my Mini-Van, is too connect a hose to the fluid pickup (using a modified old filter). The tube runs thru an old pan that I have drilled holes in, and I suck fresh fluid up thru tube and the return fluid drains from another hole I drilled in the old pan. Then I put on the new filter and pan and fill the pan. The risk with my technique, with the long tube, I start to suck some air and while doing this I do get a little foaming of the oil. No problems so far, and I have 120k on a Chrysler A-604, notorious for failing before 60k miles.

I also have a trans temp gauge on the Mini-Van and make sure I keep the trans temp below 200°F continuous and 225°F for short periods.
 
Dave4.0 said:
For the record, I had my transmission power flushed about a year ago and it runs better than ever.

That's a rarity.

"Consistently negative" doesn't mean "universally negative" - there have been good reports on getting the AW4 power flushed, but they're few and far between. Your story is not unique, but it is certainly unusual.

I've wondered, on and off, if the difficulties in the power flush haven't been from using the wrong fluid tho - just a tickle in the back of my mind. Since the AW4 "service fill" is only four quarts - but a "dry fill" is more like ten - you'd end up leaving rather more than "a couple quarts" in the case, and it would take rather more than a couple of changes to get "all" the fluid (due to Zeno's Paradox, you'll never get all the fluid with service changes - there's always going to be some left...)
 
5-90 said:
That's a rarity.

"Consistently negative" doesn't mean "universally negative" - there have been good reports on getting the AW4 power flushed, but they're few and far between. Your story is not unique, but it is certainly unusual.

I've wondered, on and off, if the difficulties in the power flush haven't been from using the wrong fluid tho - just a tickle in the back of my mind. Since the AW4 "service fill" is only four quarts - but a "dry fill" is more like ten - you'd end up leaving rather more than "a couple quarts" in the case, and it would take rather more than a couple of changes to get "all" the fluid (due to Zeno's Paradox, you'll never get all the fluid with service changes - there's always going to be some left...)

I wont do a Flush, mostly due to so many negative recommendations and because 5-90 says not to :eyes: seriously..

And on that note [his recommendation] .. i do have the Transmission filter kit from summit:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-G4980&N=700+115&autoview=sku i have yet to install it, thats basically what it looks like.. i believe it is a simple oil filter... at least thats what it looks like..

When i install this i will create a walkthrough after running it for awhile.:shiver:
 
I will be interested to see that walk through as well as how that filter performs.

I am sure a true filter setup and even a trans cooler is a plus but unless you are racing, towing hard or beating the snot out of your Cherokee in real dirty conditions I have to believe it is unnecessary. If the engineers that developed the AW4 thought these items were crucial or important to maintaining the service life of the unit, they would have built them into the transmission. My impression is that an external filter setup may cause more problems than it is worth. I am thinking specifically the introduction of air in to the fluid, reliance on the factory trans fluid pump to pump fluid into areas it was not previously design for, the potential of reduced fluid and system pressure, and the addition of a handful of new points of failure and leaks.

I mean if most owners transmissions and vehicles last 150-200 thousand miles of on and off road use with regular maintenance and the standard setup why change it. Besides, why would you want to extend the life of the transmission any further anyway considering the rest of the vehicle is likely to deteriorate at the average rate and miles as well.

I wish someone would develop a paint chip, seat tear and rust filter for my Jeep so the rest of it would stay shiny and new forever.
 
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