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High mileage transmission, change fluid or not?

He said fluid exchange, that is perfectly fine. If the transmissions pump itself is pumping fluid out that will not harm it.

You are just removing the fluid with no machines involved and adding new fluid in by hand.
 


There is a big difference. They make fluid flush machines and fluid exchange machines.

Flush machines use there own pump to force new fluid into a transmission and push the old fluid out. That is the best way to have clutch material get moved around and clog things like the valve body or feed lines inside the transmission.

Exchange machines and or doing the method in the previous posts use the transmission pump itself to do everthing. There nothing forcing fluid in and out and way less chance at internal issues. There are many vehicles out there with no internal filter or that have no way to remove the pan because they don't have one. They use plugs on the side to determine fluid level, so exchange machines work great, have it do the work for you then top off the fluid untill it comes out the full level plug hole.
 
never seen a powered flush machine, they all work off the tranny pump as far as ive seen. both rad cooler lines get hooked up to it, and they run the engine it till its flushed out.

that act can be done at home, with 2 pails, and should not be done on a high mile tranny with burnt fluid ever, or it can die. cant say this enough your tranny can be dead before it gets put in gear. seen it happen a lot.

the only people who should ever get a flush are the people who have owned the car since new and serviced the tranny every 50,000 miles of its life time, all others, never flush it.
 
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Scottydoggs said:
never seen a powered flush machine, they all work off the tranny pump as far as ive seen. both rad cooler lines get hooked up to it, and they run the engine it till its flushed out.

that act can be done at home, with 2 pails, and should not be done on a high mile tranny with burnt fluid ever, or it can die. cant say this enough your tranny can be dead before it gets put in gear. seen it happen a lot.

the only people who should ever get a flush are the people who have owned the car since new and serviced the tranny every 50,000 miles of its life time, all others, never flush it.
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He already stated that his fluid was not burnt, so I highly doubt exchanging the fluid will cause any issues.
 


Scottydoggs said:
he said it was dark, im assuming he dont know what burnt fluid smells like, cause if its dark brown to black, its burnt.
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Did you even read this thread?
He has stated that his mechanic told him the fluid didn't smell burned, and we all know how mechanics will make stuff up to make money off you, his mechanic even suggested to just drop the pan.
NotEnoughGPs said:
I have already removed the dipstick to check the color of the old fluid, it is light brown in color, not dark brown or black. And there is no burnt smell at all.
A local GM mechanic, who has also done extensive work with GM transmissions, was able to confirm that the fluid does not have the burnt odor, which he said is a sign that the transmission is toast. The brownish color is not good, according to him, but it is the original factory Dexron 3 fluid, so he says to expect that. He said, from experience, that cars driven in the city in constant stop/go traffic, and idling for long periods (especially in hot weather) have the most early transmission failures due to the fluid breaking down. He said if mine is still shifting properly at 241,000 miles, that I must do a lot of open highway driving. I can approximate that 40% of my driving is at speeds of 25-55 mph, and about 50% is at speeds 55mph and higher. My 40th Anniv. spends very little time in heavy city traffic. Also, I drive in mostly flat terrain, and I have never towed a trailer, camper, boat, etc.
He also said that one bad thing is that the filter is, by now, all saturated with dirt, clutch material, and stuff.
He strongly advised against any type of flushing, as that would cause more problems than it will solve. So, he advised to drop the pan, install new filter, Dexron 3 fluid, and perhaps 1 bottle of a transmission additive. Then drive it for a few thousand miles. Then drop the pan, and install another new filter, and new fluid and a transmission fluid additive.
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yup i did. he said its dark. dont care what a mechanic says ever, why? cause i trust very few of them. id still not double pan drop or flush it.

the clutch material in the fluid could be all thats making it work at this point, a flush or double pan drop type deal could end up a bad thing. not worth the extra risk to me.
 
Fluid exchange: remove all fluid from transmission.
Fluid Flush: same as exchange, but chemicals are used to clean and remove sludge and build up

Exchange is good. Flush is bad.

Now back to my popcorn.
 


Scottydoggs said:
yup i did. he said its dark. dont care what a mechanic says ever, why? cause i trust very few of them. id still not double pan drop or flush it.

the clutch material in the fluid could be all thats making it work at this point, a flush or double pan drop type deal could end up a bad thing. not worth the extra risk to me.
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If the mechanic was bsing him he would have told him the trans was shot and quoted him a price for a rebuild or a new one.

Sent from a galaxy far far away.
 
I have removed the return line going to the transmission. Wow, GM engineers sure don't leave much room to get a 18mm open ended wrench on that fitting.
Anyways, I am on the way to a store to get some magnets to place in the trans pan before I reinstall the pan. Then I am going to pour in the new trans fluid, and use the 3 second start procedure to remove all of the old crappy transmission fluid. I have a large hose on the end of the return line with a hose clamp, and I have the end of the hose in a clear plastic jug. That way I can tell when the old transmission fluid is finished draining out of the trans, and I will be able to see the new transmission fluid. When I see the new trans fluid, I will cease starting the engine, and I can proceed to hooking up the return line again to the transmission.
BTW. These steps are outlined on 02NavyBlue's write-up in the "How to write-ups" section (dated June 13, 2013). His directions of how to safely remove all of the old transmission fluid has been confirmed on other GM forum pages. There is zero chance of causing any harm, as this procedure has been used over and over. This is not a back-flush, and it will not dislodge any particles into the transmission unlike the "Transmission Fluid Flushing" machines that service centers use. It is completely safe as folks on Corvette forums and even foreign cars forums do this procedure and have never said that is caused harm to their tranny. My next door neighbor, who has worked on GM transmissions for 25+ years also said it is safe to do so.
In the 4T65E transmission, this "back-flushing" procedure using the transmissions own pump will remove up to 10 quarts of old transmission fluid. It will not remove what is in the converter. I am thankful that I took the time to read through the "How to write-ups" thread, or else I would have never known.
I will be providing another update later tonight.
Thanks everyone for your feedback!
 
NotEnoughGPs said:
In the 4T65E transmission, this "back-flushing" procedure using the transmissions own pump will remove up to 10 quarts of old transmission fluid. It will not remove what is in the converter.
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Where does the extra fluid come from? Dropping the pan is 5-6 quarts.
 
Yeah, last pan drop I did on my 4t65e was about 8 quarts.
I was to understand that doing the fluid change that way does the torque converter though. Maybe that was just for the 4l60.

Sent from a galaxy far far away.
 


Bronco Boy said:
Where does the extra fluid come from? Dropping the pan is 5-6 quarts.
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I removed 8 quarts, that includes the amount in the filter, and the accumulator (I am installing the Intense Street/Strip Shift Pak)
After doing the fluid exchange procedure, I expect to get about 2 more quarts.

 
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