trans fluid change...

Well I've had my jeep for about 1 yr now, and just found out that the trans fluid has NEVER been changed. Might explain why it slightly hesitating on shifting. So 111K miles on it, I'm changing over to amsoil, but with it never being changed is there anything I should do to help clean it? Other then change filter/gasket and run a full flush. I searched but didnt really find anything definite on it. Thanks all :wave:

Draining and even dropping the pan is only going to get a portion of all the fluid. The rest of it will be trapped in the torque converter and transmission body. I would recommend dropping the pan and cleaning it out, then sealing it well. Drive it, and in a few weeks simply pull the plug and refill the remainder. Do that again a third time in a few more weeks and you should have the majority of the old stuff out.

if you have a trans cooler, unplug the inlet hose to the cooler, put the hose in a large container and start the engine. old fluid will go into the container, careful not to let more than 2-3 quarts go into that container. stop the engine,add an additional 2-3 quarts to the transmission and repeat. continue to do this until the container has clean fluid coming out. i do this about once a year in addition to changing the filter and cleaning the pan.

jxj said:

if you have a trans cooler, unplug the inlet hose to the cooler, put the hose in a large container and start the engine. old fluid will go into the container, careful not to let more than 2-3 quarts go into that container. stop the engine,add an additional 2-3 quarts to the transmission and repeat. continue to do this until the container has clean fluid coming out. i do this about once a year in addition to changing the filter and cleaning the pan.

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Dang, you do that every year?
I just drain the oil and replace the filter about every other year or so on my '90. I don't even think you need to change the filter that much but I do it anyway. Over 300k miles on the tranny and still runs strong.

I start by dropping the pan and replacing the filter. Then I reinstall the pan and refill the trans with a Dexron-certified fluid. Next, the fluid return line (from the cooler to the trans) gets disconnected at the trans, extended with a piece of clear tubing and routed to a separate container.

Start the vehicle and let it pump out approx. 1 qt. of fluid. Then refill the trans through the dipstick. Start it again, pump out another qt. and refill. Do this until the fluid coming out is nice and bright red. Once that occurs, you have exchanged all of the old fluid.

I've read bad things about those "tranny flush" services from places like Jiffy Lube. I wouldn't recommend it if that is what you had in mind.

Also, the general concensus is that the AW4 does not respond well to synthetic trans fluid and can result in a significant drop in gas mileage. Do search on this for more info.

Good luck.

NeoMax said:

So 111K miles on it, I'm changing over to amsoil

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I hope you have enough money saved up for a new transmission...

I'd say the best thing you can do to be good to your tranny is to add a universal transmission cooler in front of the radiator/condenser. It is easy, just make sure it is on the line going to the radiator, not coming back from the radiator. Doesn't have to be big, just smallest size. Helps a good bit! Also, don't add that Amsoil. Go with Castrol non-synthetic available at AutoZone. Excellent stuff. Synthetic is not good for trannies.

ACE said:

Dang, you do that every year?
I just drain the oil and replace the filter about every other year or so on my '90. I don't even think you need to change the filter that much but I do it anyway. Over 300k miles on the tranny and still runs strong.

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How many quarts does it usually take before everything is clean? I think the AW4 holds around 8qts. total.

NeoMax said:

Might explain why it slightly hesitating on shifting. So 111K miles on it, I'm changing over to amsoil, but with it never being changed is there anything I should do to help clean it? Other then change filter/gasket and run a full flush.

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First before doing anything, I would adjust the cable at the throttle body to see if that improves the slight hestitation at shift points. It's simple and only takes a few minutes.

Then address the trans fluid ... and at this point, I would stay away from Amsoil. I personally have nothing against Amsoil ... but your trans may not like the change since the same fluid has been in there for over 100K. I believe the factory recommends changing every 20k miles.

When you say "full flush" .... I'm assuming you mean evacuating the trans and converter with the proper equipment ?

My advice: At this point I wouldn't do a "full flush"---just adjust the cable, change the fluid, filter, drive it and see what happens. If the overlap improves then I would go for a full evacuation and change to whatever oil your heart desires after verifying there's no metalized particles sitting in the pan.

Whats the big deal with Amsoil anyway? I have 160K miles on my AW4 and it shifts like new using standard Mopar blend...


Good luck with it.

ZmOz said:

I hope you have enough money saved up for a new transmission...

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*sigh* nice contribution with facts to back it up...anyways:banghead:

I might go with something other then amsoil, just they are very trusted and have been around for a good long while. I have done a lot of research on here, general consensus is Mobil1 ATF is really bad and drops mpg, STAY AWAY from anything castrol i guess, but I havent heard anything about amsoil, just people are scared of synthetics all together.

gw204 said:

I've read bad things about those "tranny flush" services from places like Jiffy Lube. I wouldn't recommend it if that is what you had in mind.

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ya me too dude, I was planning on doing a full flush as per the instructions a few have given on here. Really what I was asking was if there was anything I should do like helping the switch over to new fluid, especially after it being so long since new fluid. God I never knew how badly my parents take care of their vehicles :tears:

again thanks to all, its all very appreciated :sunshine:

NeoMax said:

I have done a lot of research on here, general consensus is Mobil1 ATF is really bad and drops mpg, STAY AWAY from anything castrol i guess

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General consensus where? The checkout line at k-mart? If there's *1* person that tells you that I'd be surprised, and that person is an idiot. Mobile 1 products are all very good and improve mileage in just about anything.

However, there are several reasons you should not use synthetic in an AW4, especially one with over 100k on the original fluid. First of all, with ok maintainence (which you haven't had) they will easily last 3-400,000 with the cheapest fluid you can find. Secondly, the AW4 has been known to dislike synthetic fluid. Third, putting synthetic in ANY tranny with that high of miles and no fluid change is suicide. Finally, Castrol products are not bad. They're not amazing, but they're nothing to stay away from. In fact, their synthetic motor oil is one of the best.

ZmOz said:

General consensus where? The checkout line at k-mart?

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lmao I DID say I did a lot of research on HERE (pertaining to the forums.) one key thread is here http://www.naxja.org/forum/showthread.php?t=24728&page=2&pp=15&highlight=amsoil
Many people disliking Mobil 1 a lot and having same results of it being bad ATF while amsoil is superior. 5-90 did a lil write up on fluids, and a BIG FOOT IN MOUTH on my part, and i'm sorry, I said Castrol I meant Quaker State, I always get those mixed up.

I suppose I'll just go with regular non-syn fluid. Saves me some money at least, just trying to give the jeep the best heh. Thanks all. :sunshine:

nothing but redline oil hits any part of my car, and i dont have an Auto, but since this debate can of worms has opened up - ill tell you that synthetics are KING and work great. However - when you change your engine to synthetics - you have to change the oil after 300 miles the first time because the synthetic cleans everything so well that it will break down all the old organic stuff there. Also if there were any leaks that the organic stuff had self pluged- expect to see them again. Im not sure if this holds true to transmissions, but i have heard much about engines this way

(i interned at Red Line Oil during summer - thats how i know this stuff and can afford to pay for it...)

food for thought
-XJ_Ranger

I just got done wiith my annual flush... drain pan (2-3 qts), refill with regular ATF, drive 10-15 miles. I repeated this 4x, went through approx 2 gallons of fluid, then primed & spun on a new NAPA Gold filter (I have a remote filter adapter)

Should be good to go for another year/20K miles, unless I get really mean to it somewhere.

The Castrol ATF from Autozone is what I used. Good stuff.

I was always told that when you have that many miles on your trans and the fluid has never been changed, then it will kill your trans. That's why I haven't done mine with 135,000 on it. Doesn't look like it's ever been done either, the fluid is just barely dark red.