DIY Transmission flush with cooler line

captaincrd · **Posted:** Fri Jan 25, 2013 12:23 am

I have not changed by my transmission fluid and filters ever and as I approach 100,000 miles I thought I better change out all of the ATF fluid. I didn't want to spend the money to take it to a shop with a flush machine. It was actually pretty quick and easy to do myself. Total cost was about $127 for 15 litres of ATF + 4 and Fram filters/gasket. I had enough extra fluid so I also change the transfer case oil at the same time. Thought someone might find this useful so I posted it.

1. Dropped the pan and measured the fluid that came out (about 5 litres)
2. Put in the new Fram filters, cleaned up the gasket surfaces and installed the pan with the included gasket. (Make sure the tube and bushing are completely seated. I had to fool around with it a bit to get it all the way in)
3. Add 5 litres through the dipstick tube.
4. Disconnect the passenger side transmission line where it attaches to the cooler. Access is pretty good to this connection that is in front of the radiator down low. I used a small screwdriver to pop off the clip and then the you just pull on the line and it detaches. It is a quick connect type fitting.
5. Attach a few feet of rubber hose to the line and run it into a container to catch the fluid. I used 4 litre plastic milk jugs that I marked up every 1/2 litre with a sharpie so I could see how much fluid was going into the jug. In a second clean plastic milk jug I filled it with clean new ATF + 4.
6. Started the jeep and as the dirty fluid filled the one jug I poured an equal amount of new ATF + 4 into the dipstick tube. I stopped just before the dirty jug was full, emptied it did the whole thing over again. I took out and added about 8 litres this way and the last fluid to come out was clean and new.
7. I reconnected the transmission line to the cooler and reinstalled the clip.
8. Ran the jeep for awhile and checked the fluid. I had to top it up a bit so have a bit of extra fluid around.

arengant · **Posted:** Fri Jan 25, 2013 2:47 am

Great! I will do this for my next change!

tjkj2002 · **Posted:** Fri Jan 25, 2013 8:56 am

The 545RFE holds 14 qts of ATF+4 so you changed about 2/3 of the fluid out.

flash7210 · **Posted:** Fri Jan 25, 2013 9:18 am

Not necessarily a bad method for flushing the transmission, but not the best either.
When I worked in the shop we had a device called the "T-tech."
First you pumped 12-14 quarts into the t-tech.
Then you hooked it up the the transmission cooler lines.
Then you started the engine.
The transmission would pump all its old fluid out into the t-tech and push new fluid into the transmission.
(just remember to stop the engine before all the new fluid gets pushed in)
I thought it was a great system. The only problem is that your filters dont get changed in the process.

papaindigo · **Posted:** Fri Jan 25, 2013 10:18 am

I've heard of this old school flush method but not seen a how to on the Jeep. Nice writeup. My only concern would be with respect to the filters but I don't know the best answer as there are 2 options.
1. Do the flush per the writeup but that runs 8L/8.5qts of old dirty fluid thru the new filters or
2. do the flush with the old filters, which runs clean fluid thru dirty filters, and then drop the pan and install new filters which "wastes" 5L/5.25qts of pretty clean fluid.

I have no knowledge or opinion as to the better option. Anyone have any knowledge to contribute?

The "T-tech" is likely a more professional and perhaps better option but at $3,700+ for a new unit is unlikely to be something anyone is going to put in a DIY garage.

captaincrd · **Posted:** Fri Jan 25, 2013 11:48 am

I'm sure I changed all the fluid. The fluid coming out the line was clean. I put roughly 8 litres in dipstick tube and 5 in the pan = 13 litres or 13.73 quarts. The next day I bought more fluid and put in over a litre more to get it up to the warm line on the dipstick.

dirtmover · **Posted:** Fri Jan 25, 2013 12:58 pm

captaincrd wrote:

6. Started the jeep and as the dirty fluid filled the one jug I poured an equal amount of new ATF + 4 into the dipstick tube. I stopped just before the dirty jug was full, emptied it did the whole thing over again.

So, I'm curious, I've read about but never tried this procedure. How quickly is the fluid pumped out? Is it a race to fill and then shutdown before your catch container overflows or is it more leisurely. I've got visions of fluid spewing out all over the place and it running dry 'cause I can't keep up :dizzy:

.

I've not done the Jeep yet but with my other vehicle I use a fluid extractor to extract the fluid, drop the pan, change the filter, refill, drive for a bit, extract and refill again. This procedure only dilutes the old fluid down to about 25% but is what the FSM recommends.

racertracer · **Posted:** Fri Jan 25, 2013 2:22 pm

Can a full container of New ATf-4 be connected to the other port with another 2 foot extension, so that the fluid can be pulled fom one orifice and drained from the other ........ you wouldn't have to refill from the dipstick hole?

amslube · **Posted:** Fri Jan 25, 2013 6:14 pm

I've used this procedure on many different vehicles and it works well. The old fluid does not get circulater through the new filter(s). After dropping the pan and changing the filter(s), I generally lkook up the total fill amount for the transmission and add about 1/2 that amount to the sump before starting the engine. Watch the color of the fluid as it comes out of the cooling line. If the original was dark brown or black, like many i've done, watch for the color change...it will be almost a direct change form the old to new, then shut off the engine and top off.

Never, never, change the fluid without changing the filter. New transmission fluid is highly detergent and any sludge/varnishes accumulated in the transmission will be removed by the new fluid. In many cases, the amount of material may be enough to restrict fluid flow through an already partially plugges transmission filter to the point where an insufficient volumn of fluid can pass through the old filter and cause damage to the transmission.

captaincrd · **Posted:** Fri Jan 25, 2013 9:40 pm

dirtmover wrote:

captaincrd wrote:

6. Started the jeep and as the dirty fluid filled the one jug I poured an equal amount of new ATF + 4 into the dipstick tube. I stopped just before the dirty jug was full, emptied it did the whole thing over again.

So, I'm curious, I've read about but never tried this procedure. How quickly is the fluid pumped out? Is it a race to fill and then shutdown before your catch container overflows or is it more leisurely. I've got visions of fluid spewing out all over the place and it running dry 'cause I can't keep up :dizzy:

.

I've not done the Jeep yet but with my other vehicle I use a fluid extractor to extract the fluid, drop the pan, change the filter, refill, drive for a bit, extract and refill again. This procedure only dilutes the old fluid down to about 25% but is what the FSM recommends.

The fluid is pumped out fairly quickly and it would be easier if you had a 2nd person to start and stop the jeep. It is possible to add new fluid at about the same rate the old fluid is coming out at. I did not have a helper so I quickly went to shut off the engine when my container was about 80% full and by the time the engine was stopped the container was almost full. A bit still comes out after shutting off the motor. Although it is a rush with one person I didn't find it difficult and didn't even come close running dry on fluid, in fact I could have added fluid faster than it was being pumped out.

kjjet · **Posted:** Fri Jan 25, 2013 10:15 pm

If you go 100k before you change your fluid, then it would be good to get as much fluid out as possible. If the fluid is changed between 30 & 40k you would never have to worry about anything more than what fluid is in the pan.

Suggest Transmission, transfer case, Fnt and rear end fluid change at 30 to 40K. Do it all at one time.

captaincrd · **Posted:** Fri Jan 25, 2013 10:59 pm

kjjet wrote:

If you go 100k before you change your fluid, then it would be good to get as much fluid out as possible. If the fluid is changed between 30 & 40k you would never have to worry about anything more than what fluid is in the pan.

Suggest Transmission, transfer case, Fnt and rear end fluid change at 30 to 40K. Do it all at one time.

I have managed to keep up with regular changes for the differentials, transfer case, engine, fuel and air filters but have gotten around to the transmission. So I am glad I got all the fluid changed.

DIY Transmission flush with cooler line

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