DIY Transmission Flush - Havent read about this being done...

I know this topic has been discussed quite extensively but I havent been able to find specific details on my specific idea...for lack of a better word. My thoughts revolve around the pump inlet flush method, something that I can only find reference too when a machine is involved. I don’t have a transmission flush machine and quite frankly I have no expereince using any of those machines which is why I am reaching out for knowledge on this topic.

Alright, here's my DIY idea: Drain the fluid and pull the pan. Disconnect the cooler return line and route it to an empty container. Hook up a clear hose to the ATF pickup tube (not sure about this as I havent yet pulled the pan on this Jeep, not sure what it looks like inside the AW4) and route the hose to an ample supply of fresh ATF. I would also set up a container/catch tray under the transmission for the fluid that would normally be discharched back into the pan. I would think I would be able run the jeep and shift through the gears essentially using a new supply of ATF to flush out all the old fluid. It seems that this would basically provide the same results that a pump inlet flush machine would?

Now…what am I missing here? Im sure theres a reason why I havent read about this DIY method…. Any thoughts on this would be greatly appreciated...

I am also aware of the other methods that people have used with success but I really am only interested in peoples thoughts on this particular method.

Thanks guys!

Why don't you just keep the pan on and pull the lines?

Find the outflow line and put that into a bucket to catch it, then take the return line and pump it back in. The way I understand it you need to literally pump it back into the tranny OR have it dropped in via gravity with the container of new fluid hanging up above the vehicle.

I understand that it wont suck it back into the tranny. And the idea of just letting a bucket of fluid flood the tranny with too much fluid doesnt sound like a good idea either.

I dont know though, let me know how it turns out.

Basically you want to take the cooler line off and route it to a container for disposal (pretty common for any flush)? But then you want something that will allow the tranny to suck new fluid up?

My thought would be to remove both cooler lines, route the cooler inlet your catch container, then route the cooler outlet to a large pan of fresh tranny fluid. The problem with this is that it *could* be quite wasteful. If you did it this way too, then you could blow out your tranny cooler with air & make sure it was clean. Then once you are done, drop the tranny pan, replace the filter, and then wipe everything down with a lint free cloth.

Here's one thread on this, pretty sure there are others:

http://www.naxja.org/forum/showthread.php?t=62900&highlight=flush+tranny

Note that you cannot suck new fluid into the tranny per these posts.

So, it seems like the bottom line is that if your torque converter has a drain plug, your better off just dropping the pan and draining the converter. The problem as stated is that new fluid won't suck in anyway. Pump out some and refill would be usefull if there is no drain plug on the convertor, but you'd be better off dropping the pan first and geting that cleaned out, then flush some more through.

I know you would have to physically pump or gravity feed the fluid if you were using the return port. I believe this is beause that port is not directly conneceted to the fluid pick up tube, which from my understanding pulls fluid from the pan. If this pickup tube pulls fluid from the pan to be pumped through the transmissino why cant I hook an external ATF source to this (maybe about level with the bottom of the pickup tube to help prime the hose?)

I have read the the thread that was linked but I believe the discussion was slightly off tangent from what I was thinking. In that thread omeone stated that there is no suction to pull the fluid in...that may be true for the return port but I dont see how that would apply to the actual pick up tube that pulls fluid from the pan. The discussion also touched on the fact that the fluid coming into the transmission would be mixed with old fluid which is true as that fluid is dumped into the pan (at least thats my understanding) but that wouldnt be an issue if the pick up tube was being directly fed with fresh ATF.

I agree with most of what you are saying. You could adapt a hose into the suction port inside the transmission and let is suck in clean fluid. But at that point, you may as well just let it pump through the complete circuit and back into a big collection pan under the transmission. Really no point in undoing cooler lines, etc.

Personally, what I would do is drop the pan and clean it out. Change the filter, replace pan. It will now take 2 qts. of fresh fluid. The pan holds 2, the convertor holds 3 more, and the whole system holds about 8. No convertor plug on my 2000 though. Disconnect the return line from the cooler and run into a container. Start motor, run until about a quart more is pumped out. Stop and top off through dipstick tube. Repeat until you've run out the old 8 qt capacity or fluid runs clear. The FSM does have strong warnings about running tranny more than 1 qt low. This way you don't violate that idea.

I do this on my wife's escape all the time. What I do is take disconnect a line and put it in a catch pan. I overfill it a bit Then I run the car for about 30 seconds or until about 1 liter is pumped out. Then I add a fresh liter down the dipstick tube and keep repeating until the fluid coming out is nice and clean. The tranny pump makes sure all the fluid in the torque converter gets replaced.

Should work fine on an XJ too.

winterbeater said:

I agree with most of what you are saying. You could adapt a hose into the suction port inside the transmission and let is suck in clean fluid. But at that point, you may as well just let it pump through the complete circuit and back into a big collection pan under the transmission. Really no point in undoing cooler lines, etc.

Personally, what I would do is drop the pan and clean it out. Change the filter, replace pan. It will now take 2 qts. of fresh fluid. The pan holds 2, the convertor holds 3 more, and the whole system holds about 8. No convertor plug on my 2000 though. Disconnect the return line from the cooler and run into a container. Start motor, run until about a quart more is pumped out. Stop and top off through dipstick tube. Repeat until you've run out the old 8 qt capacity or fluid runs clear. The FSM does have strong warnings about running tranny more than 1 qt low. This way you don't violate that idea.

Click to expand...

NOT,pan takes 4qts plus,entire trans takes 12+!

RCP Phx said:

NOT,pan takes 4qts plus,entire trans takes 12+!

Click to expand...

2000 FSM for AW4 says 2 for pan, 5 for convertor and pan, and 8.45 total system. Where does this other information come from?

Flushing a transmission is a bad idea and unnecessary. It flushes out stuff that is fine where it is, and can mess things up. It's also a waste of fluid and unnecessary exposure to toxic substances.

Drain and refill.

I have used this method for decades when not changing the filter. It gets out just about all the old ATF.

Drain the pan and refill with fresh ATF.
Pull the cooler return line and connect it to a clear hose. Stick the end of the hose into a 1-gallon jug.
Start and idle the engine until 1 quart or so comes out and then turn the engine off. A helper is useful but not necessary, as the oil is not pumped out very quickly when idling.
Add the same amount of ATF to the transmission filler as what was pumped out.
Make sure to keep an eye on the jug so you do not over fill it.
Repeat the above until the fluid, in the hose, changes from a dirty color to clean. You will see the difference.
Top off the trans fluid, reconnect the cooler line and you are done.
Seal the jugs of used ATF and recycle them at your local auto parts store.

You do use a couple quarts more than what the FSM says the trans holds as the extra ATF flushes the old oil out of the torque converter.
If done right, there is nothing about this that can cause the transmission harm.
[FONT=&quot]It is not the same as power flushing.[/FONT]

winkosmosis said:

Flushing a transmission is a bad idea and unnecessary. It flushes out stuff that is fine where it is, and can mess things up. It's also a waste of fluid and unnecessary exposure to toxic substances.

Drain and refill.

Click to expand...

I would personally disagree on this. I have been doing this a very long time and yes, on occasion it causes issues, but normally only on a trans that is on its last leg anyway. The Benefit is huge to you shift solenoids and converter. Wheeling is hard on your converter and off the shelf fluid is crap.

My uncle has a Trans Flush machine in his garage all i gotta do is drive to indy with some trans fluid!

lazyxj said:

I have used this method for decades when not changing the filter. It gets out just about all the old ATF.

Drain the pan and refill with fresh ATF.
Pull the cooler return line and connect it to a clear hose. Stick the end of the hose into a 1-gallon jug.
Start and idle the engine until 1 quart or so comes out and then turn the engine off. A helper is useful but not necessary, as the oil is not pumped out very quickly when idling.
Add the same amount of ATF to the transmission filler as what was pumped out.
Make sure to keep an eye on the jug so you do not over fill it.
Repeat the above until the fluid, in the hose, changes from a dirty color to clean. You will see the difference.
Top off the trans fluid, reconnect the cooler line and you are done.
Seal the jugs of used ATF and recycle them at your local auto parts store.

You do use a couple quarts more than what the FSM says the trans holds as the extra ATF flushes the old oil out of the torque converter.
If done right, there is nothing about this that can cause the transmission harm.
[FONT=&quot]It is not the same as power flushing.[/FONT]

Click to expand...

Yeah, that's what I said too.

Great discussion guys, I think Ill just end up doing the "1qt out then refill" method as mentioned above a couple times...seems like it will cause a lot less headaches.

Not meaning to restart a dying thread but...

When I had my 85 bronco and a C4 tranny I would just do a full flush using this method.

Put the output line into an empty 5 gal bucket. take a new or spotless clean 5 gallon bucket and put intake hose into this. Dump a case plus some extra of tranny fluid into clean 5 gal bucket and start it up. it would cycle thru and pump all old stuff out. leaving fluid in tranny fresh and ready to go once i saw clean fluid cominf out of output line. I would then change the filter. A case and half of tranny fluid is (or at least was then) cheaper than a tranny service.

I dont know if the AW4 can do the same as the C4 but thats what i had planned on doing to mine as its due for its first flush.

M2C

ramjet308 said:

Not meaning to restart a dying thread but...

When I had my 85 bronco and a C4 tranny I would just do a full flush using this method.

Put the output line into an empty 5 gal bucket. take a new or spotless clean 5 gallon bucket and put intake hose into this. Dump a case plus some extra of tranny fluid into clean 5 gal bucket and start it up. it would cycle thru and pump all old stuff out. leaving fluid in tranny fresh and ready to go once i saw clean fluid cominf out of output line. I would then change the filter. A case and half of tranny fluid is (or at least was then) cheaper than a tranny service.

I dont know if the AW4 can do the same as the C4 but thats what i had planned on doing to mine as its due for its first flush.

M2C

Click to expand...

Read the whole thread again. The point is that the AW4 will not suck up the new fluid.

Here's what I do - same as LazyXJ. I do this approx every 20k-30k miles. Also known as the "poor mans flush".

Disconnect the return line from the tranny and point it towards a 5-gal bucket.
Have a buddy start the XJ and leave it idling in Park.
About 3-4 quarts will flow into the bucket, then the fluid will stop.
Once it runs dry, turn off the XJ. Fill the tranny with about 4 quarts of fluid.
Have a buddy start it again. Fill the bucket with another 3-4 quarts.
Once it runs dry - stop the motor and fill the tranny again.
Repeat until the fluid comes out red - this is easy to tell when fresh fluid comes out.
Fill up tranny to the full line. Done. Drink beer and examine your awesomeness.