Tranny Fluid Change

This might be a stupid question, but is it ok to change the Tranny fluid by just pumping it out of the dipstick instead of taking the pan off and all of that mess/fun?

It can be done. It you would be better off droping the pan so can change the filter. If the fluid is dark brown and super nasty I wouldn't touch it putting it new fluid will just cause old sluge to break loose in the tranny and clog up the valve body.

You can unhook one of the tranny cooler lines running to the radiator and it will pump it out for you. Thats if you have a the towing package

You can also use the drain plug on the pan... :shrug: You'll get about 1/3 of the capacity out that way.

The "filter" is a wire screen to catch particles, but it doesn't 'filter' in the sense of the word most people think of.

dbxtr3 said:

You can unhook one of the tranny cooler lines running to the radiator and it will pump it out for you. Thats if you have a the towing package

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You still have the transmission lines to the radiator without the towing package; you won't have the additional cooler plumbed into the mix is all.

The forward hose connector on the transmission is the pressure line.

Jim www.yuccaman.com

My preference is to renew fluid gradually if it looks neglected. Luckily the AW4 in most XJs has a nice drain plug that allows you to drain out about 3 quarts. Changing out 3 quarts at a time when you doo your oil changes should gradually bring the tranny fluid back without any drama. It would be good to drop the pan and change the filter too, maybe after a couple doses of new fliud. Dropping the pan might get a little more, but should still only be roughly 3 quarts, which is less than half of the fluid in the tranny.
The tranny line will also pump it out as mentioned above, I've done it by accident all of the auto XJ's have oil lines to the radiator, the towing package should also have a cooler in front of the radiator. Either one will have a hose you can easily disconnect, but the drain plug is really easy......

I appreciate the help. I had my rig in some deeeeeep water last weekend and think it's probably a good idea to change all of the fluids!

jeepster_259 said:

I appreciate the help. I had my rig in some deeeeeep water last weekend and think it's probably a good idea to change all of the fluids!

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Ya I saw that on youtube. All the vents will catch water! Diffs and auto.:wave1:

jeepster_259 said:

Are you saying that if the fluid is dark brown, don't even bother changing it at all? Or just make sure you change the filter when you change it?

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I wouldn't both changing it at all. It will shorten the life of the tranny due to the previous years of neglect. New fliud won't help that much.

As for your case I would change it due to the fact you may have water in the tranny which will most diffinently kill any transmission.

For the best change un-hook the tranny cooler lines it will pump almost every bit of fluid out instead of it instead of the 3 quarts you would get by suck it out or pulling the drain plug. the torque convertor holds about 2-3 quarts of fluid that sucking or drain plug removal won't get out of the tranny.

If you want to be really cautious get a hand pump from Vatozone or wherever and pull a couple of quarts through the dipstick then repeat a few more times (this is the only way to do it on most cars). If you want to be a little more aggressive pop the drain plug on the AW4 and you'll pull about 4 quarts that way. If you want to be really aggressive disconnect the cooler feed line and run the car in park--the pump will push it all out.

I would not drop the pan and replace the filter until the fluid had been completely cycled.

I just swaped my 85 XJ this summer, killed the tranny with less than 40,000 miles on it in 2 days after that. I have the TC904 in mine not the aw4.

Changing the tranny fluid is always good. Never bad!! That not changing old fluid myth is partially true for older manuals. Automajics, changing the fluid is always good. Don't flush it, just drain and refill. It will give your tranny new life!! Do it more than once if your tranny fluid is real bad. Also, if the fluid hasn't been changed for a long time you want to do the filter too, and clean the magnet on the pan.

In my experience with AW4s, if you just drain the fluid from the bottom plug, it takes about 3-3.5 quarts to fill back up. If you drop the pan, it takes closer to 4 quarts. YMMV, so add a little less than what I recommended, start up, let it warm up a bit, and then check fluid level and fill till the dipstick reads correctly.

Once you get the fluid "clean", if you'll drain and refill the 3+ quarts of tranny fluid every other to every third oil change, your tranny fluid will stay in great shape and likely never need to be flushed.