What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

99-07 Silverado tranny flush - Is this legit?

That's essentially how it's done, but with a machine it takes out how many quarts you put in.

If I was going to do it that way I would use more then a quart jug just so you don't have keep shutting it off and changing the quart.


If you are careful you can pull the plug on the trans and drain about 5 quarts. A trick I have found is tighten the bolt then loosen it or the head strips
 
The problem with this is you still have the dirty partially clogged filter in the transmission.
 
I will drop the tranny pan and replace the filter before the flushing. If 5 quarts drop out I will put 5 quarts back in. Then I will start the flush procedure as shown in the video
 
my 4L80 took 6qts with the pan drop, 3.5 with just the drain plug pulled
change the filter and replace as much of the fluid as came out with the pan drop, then do the drainplug a couple times and call it good. after 3 changes you've removed about 85% of the old oil.
 
Last edited:
Do you see any problems with it?
Click to expand...

:whistle:


I will drop the tranny pan and replace the filter before the flushing. If 5 quarts drop out I will put 5 quarts back in. Then I will start the flush procedure as shown in the video
Click to expand...

And if you do this on a high mileage neglected transmission, in a week or two you will get the added bonus of having the vehicle towed to the transmission shop to have the trans rebuilt.....:woot::woot::woot:
 
I've done it. Only did about 1/2 quart at a time - maybe I'm paranoid. Never had any problems and don't see why it's any worse than the $80 job at the oil change place, other than being more of a pain to do. To change everything, do the flush, then drop the pan and change the filter. You'll go through at least a couple gallons of fluid, though.

To be honest - I've reused fluid before that was almost new. Just ran it through a coffee filter and back down the tube....
 
Why do you say this?

The truck has 60k but I don't know the history. It may not have been changed before.

wasted wages said:
:whistle:




And if you do this on a high mileage neglected transmission, in a week or two you will get the added bonus of having the vehicle towed to the transmission shop to have the trans rebuilt.....:woot::woot::woot:
Click to expand...
 
For some reason slush boxes like to fail if they have been neglected then completely/flushed. If neglected some people have better luck by only changing a little fluid at a time, multiple times over a longer period.
 
The clutch dust/fibers mixed with the fluid fills in all the voids in the seals and Teflon rings inside the trans....it also makes the fluid have a higher viscosity which helps keep the pistons applied with adequate line pressure.

The new fluid acts like a solvent and cuts and cleans, flushes away all of the old "slurry" of trans fluid and clutch dust....and then the seals can't seal as well,the thinner fluid can't keep the pistons applied as hard,,,clutches and bands start to slip,,and the trans fails.

Leaving the old thicker fluid in a neglected trans is better, IMHO..... :dunno:
 
I had always heard that the particles acted kind of like a friction modifier for limited slip rear ends and that when you put new fluid in the clutch packs act like they are glazed. Good to know a more detailed answer.

Although I thought that analysis showed lower than normal viscosity?

First one i could find online...
http://www.blackstone-labs.com/transmission-sample-report-1.php
 
So then my 180k mile 4l60 in my Tahoe shouldn't be touched because it will fail? The fluid is clean and doesn't smell burnt or anything. The PO kept up with the maintenance according to the owners manual, So should I be worried?
 
I don't think so Glenn....my 4L80 had 175K on it, never been serviced, it was turning light brown, it had been used for towing a 5th wheel camper before I got it...maybe only 5% of the mileage used that way though.
I changed it by dropping the pan, did the filter and the pan was actually very clean, no metal of any kind (sometimes aluminum is common from casting flash) some clutch residue but not pasty at all.
I did the pan drop change then two additional changes with the drain plug only....its towed great, only issue was getting warm when climbing up to 8000' out west.
 
As long as the fluid doesnt smell burnt your ok. It is normal for it to turn brown as it gets closer to its change interval.

But flushing a tranny is a major fail, but it does make Pepboys alot of money, and as a side bonus, brings transmission shops alot of money after the filter clogs because of lack of pan removal and the tranny burns itself up. Best way to service is one is always drop the pan, change the filter and replace it till it is full. That way it changes it enough to revitalize the fluid, and not to much to cause slippage and seal leakage problems that come with aged/neglected units.
 
I did a double fluid and filter change in one month on the Avalanche back in 2011, apparently the previous owner didn't keep up on it. It was getting a bit dark, brownish in color. At the time it was at about 127k miles.

Did the double change, not back to back, and it came back to a nicer more redish color and didn't have any bad smells to it.

I ended up burning up the trans though on our way back from California, let it slip in and out of lock up too many times too soon while climbing hills, overheated it.

Now I use the "tow/haul" mode most of the time when in mountainous areas especially if the bed is full of luggage and all of us are in the truck.

If the fluid is pretty brown, I would be hesitant on doing a sever flush, just a feeling, I dunno. I don't think there has been any actual proof that it damages a trans though. Just people that say their trans died after they did it, when in actuality it was probably about to die out anyways, which is why they thought to check the fluid and saw it's condition.
 
Although I thought that analysis showed lower than normal viscosity?
Click to expand...

maybe it has to do with the way the fluid is tested... I would think anything solid that is added/ mixed into the fluid would increase its viscosity..It's just a physical fact.

I guess if they spun the solids out of suspension in a centrifuge and then test only the fluid, the viscosity readings could be lower... add a little heat and they get lower still....

Ever notice the crap they sell to pour in your engine that "extends engine life" and "restore the rings" in your engine ??? that crap is THICK...and for a good reason... it adds viscosity and materials to your oil that "fills in " the voids in metal and rubber seals as an attempt to help repair what years of neglect has done to an engine...

all that being said, once the new transmission fluid starts washing out the solids that are in suspension of the old fluid.... the seals will not hold as good,,,the pistons will not apply as hard...things start to slip and it all goes downhill from there.

As far as where the cutoff is in the age of the fluid....that's anyone's guess...
but like someone said before,, most people start looking at servicing the transmission because they noticed a change in the way its acting...and by that time it's probably already too late..
 
The way I look at it is that a 4L60-whatever takes what, 16 quarts?

If you remove 2 qts, and pour two more in, you now have 14 quarts of old oil, and 2 quarts of new oil that are mixed together. The fluid is not segregated. I'm no math major, but you'd have to go through a fair bit of trans fluid to make a significant change in percent of new vs. old with that method.

Whether you agree with it being a good thing or not, a flush is at least pushing old fluid out as new is going in.

I've tried the same thing with a contaminated power steering system (water got in there somehow) and since the fluid was pink, and I was using Dexron, it was very easy to see that it took a LOT of fluid (far more than capacity of the system) to get it to come out anything other than pink.
 
You must log in or register to reply here.

Latest Posts

Top Bottom