Brown Fluid 904 - Exchange fluid myself?

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74desertduster

74desertduster

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Is it possible to use the trans cooler lines to exchange the fluid in my 904 by having the trans pump it out one line and have the other line suck it up from a clean container while engine is running?

Thanks

Brian
 
I was just reading up on this recently!!

This should work, but only if the car in in Neutral. From What I have heard, the pump is only engaged in neutral, not park.

Run sone rubber tubing from the ends of the hose away from under the car for easier Viewing of what colour the fluid is. Once the fluid is clean, you wil have flushed the whole transmission.

Don't Forget to change your filter.
 
RobbAdams said:
I was just reading up on this recently!!

This should work, but only if the car in in Neutral. From What I have heard, the pump is only engaged in neutral, not park.

Run sone rubber tubing from the ends of the hose away from under the car for easier Viewing of what colour the fluid is. Once the fluid is clean, you wil have flushed the whole transmission.

Don't Forget to change your filter.
Click to expand...
this is correct unless you have a reputable tranny guy drill out the vaulve body so that the trany is able to flow fluid while it is in park.
 
also something else to consider when you plumb it all back in is to add an inline tranny filter.
 
You could pump fluid out via the line but there's nothing to suck fluid in. The return line from the cooler just dumps into the rear of the case.
 
are you sure? just because one side pumps doesnt nessasarily mean the other side sucks.not sure the return line pulls a vacumn
 
and if it did it even tho it dont it would be diluting in the dirty fluid. bad idea.
 
Hmmm....does kinda seem like the pump would maintain positive pressure through the cooler and then back through the return line. No reason the return line would suck on it's own, I guess?
 
There is no way to get fluid back in unless you pump it in. The return line will not pull fluid in. About the only way to do this without the proper flush equipment is to chnge the fluid 2-3 times in a week, or drop the trans and flush it by hand.

Doing it the way you suggest could starve the rear bearings of lubrication.
 
drop the friggin pan. add a drain plug while its down. robb what are ya smokin bud. mopars pump not suck lol
 
pull one line and see which end the fluid comes outta and put that end into a oil catch pan or something to hold about 12 quarts of fluid then start the engine. it sounds like it will need to be in neutral but i would say go thru all the gears and park and neutral and flush the crap outta it. while fluid is coming out dump more fluid in the dipstick tube. be sure to not run it low on fluid and keep putting new in till is comes out clean thru all gears. that is how i have always done it and it works great. usualy we did just that and didnt worry about the filter but now that i think about it the filter would be a good idea to do along with all that. i cant decide to do the filter before or after that. i think before but whichever you think would be best.
 
Dropping the pan won't do what I want...I want all/most of the fluid changed...

I may try Tyler's idea....makes sense.....or I could spend the $100 and have it done.
 
Drop the pan and do it right! Use an air hose to purge the cooler. If you have a factory converter, it should have a drain plug as well. Good time to adjust the bands while you're down there.

If your fluid is brown, the transmission has overheated. If it still shifts fine, a fluid change is wise. If it is slipping, don't expect miracles.
 
dropping the pan leaves a lot of fluid thruout the trany and in the converter. when we did just the fluid and not the filter it worked really good. it helped shift quality and slippage. sometimes it works amazing. i bought a 89 lebaron with a bad trany. it slipped like crazy. we flushed it completly and didnt do a filter and i got 9k miles outta it before the tranny went south completly. so i am a honest beliver in the way i mentioned
 
It still leaves you a dirty filter and pan !!! Do it the right way-drop the pan, replace the filter, drain the converter and flush the cooler. And if you are real smart you will leave a flat magnet in the pan. It keeps any metal shavings from getting pumped thru the tranny.
 
once you've seen what the bottom of the tranny pan will look like when you pull it off, you will be taking that off and changing the filter every time. My old 904 and the tranny in my 95 blazer had lots of filings/junk at the bottom of the pan. If you are careful when you take the pan off you won't even spill a drop on the ground.
 
lots of people put the magnet in the pan but if you are catching metal on that magnet and the pieces are big enough to be a issue it is to late i think. i would say the filter is a great idea but if you are on a budget it is the less important one imho
 
My Dakota R/T and both of the company Dodge vans (V6 and 360) the tranny and rear ends have magnets in them. Helps keep all the little trash out of the oil and filter. Mopar put them in for a reason.

..even my Mustang has them.
 
Ok....got the filter and will drop the pan in a couple weeks....don't have the time right now but wanted that brown fluid gone until then.

So, I used some clear plastic tubing from Ace hardware and ran it from the pressure side line of the pump (passenger side on my Duster) into a large bucket.

Watched the brown smelly fluid being pumped out as I added new fluid into the dip stick tube....careful to not overfill.....had fluid markers on the bucket so that helped.

Worked very well and hardly took any time. Just had a helper keep the car in drive and that was it.

Now the fluid is nice and pink/purple again....although I know the filter must be bad based on what the fluid looked like. Will tackle that very soon.

Thanks for all the inputs!
 
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