Transmission flush?

[dogfriend]

Originally posted by redrig
i was looking through the haynes manual and it said 4 quarts (drain and refill) is that not right? but as jason_25 pointed out hes doing a flush.

The Haynes manual is talking about the amount held in the pan. If you drop the pan, you need approx 4 quarts to bring the level back to normal.

The whole transmission (5R55E) holds either 9.75 quarts (9.25 liters) for 2wd or 10 quarts (9.55 liters) for 4wd.

The extra is the amount held mainly in the torque converter that doesn't come out when the pan is dropped. You must do a flush to get the old fluid from the torque converter since there is no way to drain it (short of disassembling the transmission).

 

[Dmann99xls2wd]

So if I drain my pan 3 times I have replaced 12 quarts of fluid?

 

[dogfriend]

Originally posted by Dmann99xls2wd
So if I drain my pan 3 times I have replaced 12 quarts of fluid?

Yes, that would be correct, but the next question would be: 'Which 12 quarts would be replaced?'

If you dropped the pan immediately after adding the first 4 quarts, then you would be draining out the new ATF that you just added. If you start the engine and/or drive the truck, then the new ATF in the pan will mix with the old ATF in the torque converter. Then when you drop the pan, you will be draining a mix of old and new.

That is why we are saying that you must do a flush to get all of the old ATF out if you want to completely replace it.

The two ways to flush are:

1. Using a special machine that forces the old fluid out of the cooler line while simultaneously replacing it with new ATF.

2. Doing the "add one quart method" where you let a quart drain out of the cooler line, stop the engine, add a quart through the dipstick, drain another quart, etc.

Both of these methods allow some mixing of the new and old ATF, so they would typically take more than the 10 qt capacity of ATF to make sure that most of the old stuff has been purged out.

I have had method 1 done by the dealer at 32K, and I did method 2 about 79K miles . I used 12 qts to flush mine, but the fluid was not very dark when I started.

 

[Dmann99xls2wd]

Dogfriend,

Thanks, that makes sense.

Either my trans or my power steering is now making a whine since I replaced the fluid in both systems with Mobil One ATF. Everything works fine but it is making a whine. I don't know if I got air in the system or what. I know I ran it 10 yards up the driveway 2 1/2 quarts low on transmission fluid and the trans started to slip or come out of gear. I later filled it but I have only driven it around the block and it whines. Tomorrow I'll check the fluis level, warm it up and check the level again. It may still be low on fluid.

Dan

 

[dogfriend]

According to this thread, pwr steering whine , the power steering pump will whine with even the smallest amount of air in the system.

My Ranger used to whine, I don't notice it with the Explorer.