Just did my own 4.8is transmission fluid, oil pan drop, and filter...and consequences...


So I thought I'd post my own story/saga... haha . I just finished the trans filter, oil pan, and refill, on my 2005 4.8is at 72,000miles. I had a few twists and turns in getting the right parts and fixing my resulting "lurch issue". My 4.8is was born in April of 2005 which made the difference of a metal pan with integrated fill hole and no transmission side fill option. My ZF trans also has a flat paper-like gasket. Ordering online got me the wrong plastic pan with no fill hole and an o-ring type gasket. Visit to the dealer got me the same thing until they looked it up by VIN# and so I got the gasket and filter from them - about $100. I found out later I could have gotten the correct entire kit here. Yours may differ or have a plastic pan and different seal. Check the numbers by crawling under and looking at the pan.

I ordered (6) L of the ZF LifeGuard 6 online. I wanted to have extra just in case since supposedly only (4) L comes out. I used all but about .5L to refill!

Very Important! Download and read about your transmission and the specific fill instructions within!

1. I drove up on two pairs of rhino ramps and had the X's air ride set to the highest setting for good level clearance.
2. Opened up the Fill hole first. I call this insurance! Make sure you are able to refill. Then the drain. I have the metal pan version so... 17mm hex. Small hex (5mm) for my own drain plug. My oil of black - time to change. This is went I realized that more oil comes out when warm than cold AND it's freakin hot! Remember that when filling! If you fill with the trans too warm your result will be underfilling! You'll see from the .pdf link above.
3. T25 Torx socket needed to start dropping the pan. I loosened everything so it's basically hanging down on the bolt heads. Be ready with a catch pan like mentioned in start of this thread. I dropped the pan from back to forward to get the left over oil (quite a bit) in the pan poured back in the catch pan.
4. Take down pan. Pull down filter. I didn't realize that there was a little multi-ribbed gasket that is supposed to be on the filter housing until I tried to install the new filter and couldn't get it to fit. Then I realized the old gasket was still stuck up in the trans. I was able to get it out with my pinky finger finally while getting rained on by old fluid. New filter seems to barely "hang on". I bet, like mentioned earlier, the pan holds it up in the end.
5. Clean the pan. I used BraKleen cleaner on the entire pan and wiped the periphery of the mating trans interface as well. Cleaned out the pan but left the magnets in. I noticed a light metallic sludge on the magnets but no shavings, etc. I was able to wipe it off with a finger to start. When I was done cleaning with brake cleaner, I would have eaten off of it. I didn't want any foreign crap going back into the system.
6. Prepped gasket with some gasket prep sealant. My pan had been leaking prior so I wanted to make sure it would be sealed. If you have a rubber seal you may not need to do this.
7. Placed gasket on pan then carefully placed up on transmission while putting screws back in. You really need three hands for this! Bolts get tightened in an alternating sequence. Torque specs are 9 N-m.
8. I let the gasket seal sit for an hour to set. Tightened the drain plug. Then, time to pump in the fluid. I used a fluid hand pump that fits both small and large mouthed bottles. Other than it made my arm cramp, I loved it! I used ZF LifeGuard 6 fluid. Started dribbling out. Finger tighten the fill.
9. Get in the car and start. Run through the gears in Tiptronic mode. Wait about 3 secs in each gear including reverse. About the highest gear you can reach this way is 3rd. LEAVE THE CAR RUNNING with AC and Heat on full!
10. Get under the car and open fill. Pump a boatload more in until it starts leaking out again. Careful of the exhaust!
11. By this time the trans fluid is probably too hot. Wait until the car cools down and follow the instruction in the above linked filling procedure or linked here again on page 5! Too warm = under-fill.
12. Drove for a bit, like 10 min trying out gears, etc.
13. Clean up! You may be done and happy or...

PART 2! The Lurch!

After a week my car started shifting down from 2-1 with a lurch or a feeling like I was getting rear ended whenever I came to a stop. Very harsh. Upshifts were harsh too.

My 2 cents is that the transmission didn't "know" it had new fluid and was operating on settings it "learned" or adapted to.

Took to my mechanic who reset the "Adaptations" in the transmission and then updated the software to the latest for the ZF. It was the best $180 I've spent! It shifts better now than before I even did the fluid change! Do these two things first if you have issues after flushing your fluid or with the "lurch" or harsh shifting in general.

Happy motoring! Hope this was helpful.