E38 Transmission Flush DIY

[racer2086]

Hey E38ers. My first formal DIY, I think. Skip to the bottom for the back story. DIY instructions below.

This was done on a 98 740il, 164,xxx miles.

Tools and supplies:
T27 torx bit (pan bolts)
H7 hex bit (drain and fill plugs)
13mm socket
Ratchet
Phillips head screwdriver
Any necessary extensions or adapters based on your tool set*
Two (2) ~5ft clear vinyl tubing 1/2" ID x2 from Home Depot or Lowes
2 hose clamps of the right size for the OD of your tubing
5 gallons of your choice of transmission fluid (I used Valvoline MaxLife High Mileage Dex/Merc ATF -- BMW LT71141 compatible according to bottle label)
At least a couple of receptacles for the old fluid (enough to drain the pan and get you through at least one bottle, so you can use the empty bottle after)
A fluid hand pump ($4 at harbor freight -- it works great)
|--Pan gasket
| Filtran filter (sold as a set from OEMbimmerparts)
|--Filter o-ring
Transmission cooler o-rings (BMW pn 17-21-1-742-636) should be in stock at dealer
Plenty of paper towels and rubber gloves
Ramps or something to get the car in the air enough to get under it
A second helper


Ok, so for the steps:

1. Drive the front of the car up on ramps (my case). Apply parking brake.

2. Make sure you can open the fill plug! There is about 1.5-2 inches of space between the fill plug and the exhaust pipe. I could only fit my 3/8" drive H7 bit with my 3/8" ratchet in there. The 1/2" ratchet with 1/2-3/8" adapter wouldn't fit. Mine was SO tight, I had to use a long 1/2" extension stuck on the 3/8" ratchet to crack it loose. I knew that I was either going to break the ratchet or my hands. Fortunately it cracked loose and I only skinned my hands on the exhaust pipe. Once cracked loose, just leave there hand tight.

3. Drain the pan. There is only one plug on the bottom of the pan. It is at the front center of the pan. Use the H7 to get that one. Gather the filter and pan gaskets while this is draining. Took some time.

4. You can start cracking loose all of the T27 torx bolts holding the pan up while it's draining also. That's the next step; get all those out.

5. If the pan isn't already falling off in your face when you get the bolts out, lightly tap it with the side of the ratchet and it'll come loose. I had to tip mine down at the front a little to get the remaining fluid drained out of it, since the front was up on ramps.

6. Set the pan to the side. Marvel at the disgusting fluid and feel sad at all the metal filings stuck to the magnets...





7. You will now be left with your transmission filter stuck onto the bottom of the valve body. Leave a large catch pan underneath the car, because it'll be slowly dripping fluid from all over.



8. There are two T27 torx bolts holding it to the valve body. Remove those, apply a bit of downward pressure to pull the filter output with o-ring out of the valve body.

9. Now your filter is removed, you can see the full valve body. Pretty cool. Pretty clean too.





10. Install the new filter o-ring on the filter, press it back into the valve body, and tighten the two torx bolts for the filter down.

11. Make sure to clean the pan and magnets thoroughly. I drained what I could out, and used paper towels to get the rest clean. I'd say I got the magnets 99% clean and the pan 100% clean. Unfortunately, I didn't take a picture of it, but it looks like this:



12. Install the pan with the new pan gasket. Tighten the drain plug. Remove the fill plug and fill pan with new fluid using your pump until it flows out the fill hole. Replace fill plug. Don't leave rubber gloves and your camera with your friends; they will take stupid pictures.



13. Go to the front of the car and remove the plastic under covering (need Phillips screw driver).

14. Locate transmission cooler lines bolted to cooler at front driver side of radiator. They are the lower set -- power steering is the upper set (in this picture, the transmission lines are already disconnected; the lines visible are the power steering lines). Use your 13mm socket and (likely extension) to remove the 13mm bolt. Give a small tug to the hoses and they should pull out. Make sure to get the old o-rings also. You will lose some fluid out the cooler so have a catch pan, but it's not much.



15. Work hoses so they stick out bottom of car and attach clear tubing with hose clamps to them.

(This picture was taken part way through flushing procedure. Look at how black the fluid was!)



16. Once you have the hoses hooked up, blow into the ends to differentiate between the return and output hoses. The return hose will let you blow the fluid out and then have no resistance blowing into the transmission pan. The output hose will not let you blow into it. It'll have noticeably more resistance to it.

17. Stick the output hose into a catch pan. Jam the hose from your hand pump into the end of the return hose (my harbor freight pump hose fit perfectly in the 1/2" ID clear hose with just enough resistance to not need a hose clamp).



18. So here's the deal: you are going to have your friend start the car and run through the gears. It will pump out old BLACK fluid into your catch pan. While this is going on, you need to be pumping your butt off to refill the pan. Make sure the hoses are tight in the hand pump and tight in your clear hose. I had a blow out all over my leg, lol.

Here's the thing, you will NOT be able to keep up pumping. So, after an arbitrary amount of time (or until you start seeing bubbles out the output hose, have your friend turn the car OFF to let you catch up. Fill the pan back up with an arbitrary amount of fluid that seems like enough to fill the pan.

Start the car back up and watch it spew out more black fluid. Do your best to keep up pumping in new fluid.

***Reminder, secure the output line into your catch pan. Like turning on a garden hose and having it push backward, this will do the same. If you are not ready, you will have quite a mess on your hands.

(Just a comparison of the old and new fluid)


19. When you start seeing clear fluid coming out the return line, you're in good shape to turn the car off. I pumped an arbitrary amount of fluid into the pan after this to fill the pan up as much as I could to be able to back the front off the ramps and the back up onto the ramps (for topping off the trans pan). I'd say pump more than you think, because the pan itself holds something like 6L. I didn't pump enough, because I could feel reverse slipping while going up the ramps. Eeeekkk... There is NO way I could get to the fill plug any other way.

20. Once you have access, remove the fill plug. I held the hose in the transmission fill hole while my friend pumped the fluid in with the hand pump. Do this until it overflows.

THEN, have your friend run around and start the engine. I really don't like being under cars when they are running, let alone with my hands at the fill plug right next to the hot exhaust pipe.

You need to make sure your transmission is between 30-50*C. I estimated this arbitrarily, so I then just filled it until it came out the fill hole.

21. Pop the fill plug back in and take for a spin.

My shift were waaaay smoother and the transmission is silent now when idling. There really was a subtle but noticeable difference. So far, so good with it. My torque converter is locking up again, although it doesn't feel like it'll last long that way. Transmission feels just as strong as it did before. I've done less than 100 miles of city driving, though, so the jury is still out on that one. I'm driving to Atlanta today...that'll be the real test, knock on wood.

The job took me about 6 hours surprisingly. There are a lot of steps and getting under the car with ramps is time consuming. It also doesn't help that I needed to go back to advanced auto two more times at the end for fluid to top up the pan.

Cost was about $130 for fluid and $60 for the filter kit. The tubing and other hardware was probably another $10 and the o-rings from the dealer were $5.

It was definitely worth the change (for now), but I will definitely pay someone to do this next time (as long as they flush it this way, not those pressure flushes with machines, that from what I read will kill your transmission). It's an annoying job.

Hope that helps.


Backstory:

Anyway, there is a bit of back story to this I'll provide quickly. I inherited this car from my mom at about 153k miles. The transmission was having the infamous torque converter shudder that it had been doing for easily over 50k miles. When I started driving it, it slowly drove me nuts to the point where I tried Dr. Tranny's Instant Shudder Fixx. I put two tubes into the transmission, which was full of original fluid and filter. It worked instantly!

But it only worked for about 7k miles, before it came back. I added a bottle of their ATF protectant, which did smooth out the shifts and reduced the sound of the shudder. In my OCD quest, I added another tube of the instant shudder fix, which didn't do much other than make the shudder noise more noticeable. I gave up and was satisfied that I tried everything to cure the shudder other than dropping big $$$.

Then months later merging on the highway, the torque converter decided to grab and slip instead of just slip. This caused an unnerving lurching to the car under light acceleration.

And that was the point at which I said, OK, I need to just change the fluid and get this thing back to normal, which means either slipping or (hopefully) improved TC.

[Mayorchuck]

FLickr pics not showing.

[740il97g]

Thanx for the write up. I will be doing the same soon. But I think I'm going to use royal purple. Keep us posted on the torque converter I believe my car is having the same issue.

[racer2086]

Pictures should be fixed.

Just did about 660 miles round trip from Gainesville to Atlanta for the 3 day weekend. Car drove great.

Initially, the torque converter worked quite well. The more miles I logged, though, the more it started grumbling. I'll drive it a bit more, but I won't be surprised if it's grumbling like it used to.

The drive had a lot of hills. What I noticed is that at light throttle coasting down one of the hills, there was a slight slight whine. I used a Filtran filter. Not sure what to make of it, but it's so minor it doesn't bother me.

The transmission runs very quiet and shifts very well.

[M I C H A E L]

Nice write up man!! good job and thank you! Glad it made improvement for you. Youd be suprised what new clean atf will do for a transmission.
How many quarts did it take you? 9?

[seamus2154]

I think a rebuilt converter will solve your problems as your trans seems fine otherwise.

[Timm]

Well done, and thanks for the write-up. I've not seen a fluid change done like that before, but it is a good way to get rid of the old fluid that normally resides in the torque-converter.

[racer2086]

Nice write up man!! good job and thank you! Glad it made improvement for you. Youd be suprised what new clean atf will do for a transmission.
How many quarts did it take you? 9?

Thanks! I knew the new fluid would help, I just didn't know if it would do more harm than good. I have no idea how many quarts it took, as I ran as much through as I needed to in order to start seeing "cherry red" fluid coming out. In the end, I flushed with 4 gallons (16 quarts) and topped up with another gallon or 4 quarts.

I think a rebuilt converter will solve your problems as your trans seems fine otherwise.

Yeah it definitely would. I've come to that conclusion at this point. However, the expense of such a repair would neighbor in the $1000 range. For my transmission with (now) 165k miles, that just wouldn't make much sense. I drove the car today and it really does drive well. The TC grumbles occasionally, which is a huge improvement from before. It grumbled a lot more on my trip back from Atlanta, but I think that was because I had a car of 4 people and trunk full of luggage trucking up pretty big hills. I feel like the TC is just on the "edge." Probably a bad internal seal. Sad really...ZF really dropped the ball on these torque converters.

Well done, and thanks for the write-up. I've not seen a fluid change done like that before, but it is a good way to get rid of the old fluid that normally resides in the torque-converter.

Thanks, Timm! I've used your site more times than I can count.

That was exactly my goal -- to completely change over the fluid. Reading about it on the board (locknload did this), it seemed to make so much sense to just let the transmission pump its own fluid out for you. In reality, I could do the whole job in a fraction of the time now. With a lift? 1.5-2 hours tops.

Here's the thread locknload started: http://forums.bimmerforums.com/forum....php?t=1913708

[Almar 48a]

Good write up racer2086. I had the same exact problems with my newly purchased 01 E38. http://forums.bimmerforums.com/forum....php?t=1899485 New to the BMW world I had no idea what was going on untill I came across this forum. I used Valvoline transmission fluid with a Filtran filter and the car runs 100% better. A must do.

[TheLadiesMan]

Did the shuddering come back?

[racer2086]

The bad feeling grab and slip is gone. The converter locks up properly now PART of the time depending upon load, weight in the car, and trans temp.. The converter is essentially bad, I'm just trying to make it more driveable without replacing it. The Valvoline Maxlife has some additives in it to help high mileage transmissions, including one for TC shudder. So it's better, but not totally.

[M I C H A E L]

the additive in the atf has a seal conditioner too to help. It's essentially a bandaid so to speak. Glad it's helping you now. Now you're able to drive a bit more.

[mgoods50]

I don't understand using the hand pump. I mean, I know you have to fill the pan as much as you can initially.

Is there no suction on that side? Can't one just hold the hose in the fresh fluid and let the transmission pump do the rest? I always use this method when flushing PS systems on the E36 and E38.

[Singh336]

Sorry to bump this topic, but i have an 01 740il and the transmission will not go into sport mode anymore, when you shift it into 4 the S does not light up anymore. The shudders have begun and one day none of the gear lights lit up on the dashboard, very strange.

Any idea? I'm going to try to do this flush as shown above.

[MaximusBKK]

I don't understand using the hand pump. I mean, I know you have to fill the pan as much as you can initially.

Is there no suction on that side? Can't one just hold the hose in the fresh fluid and let the transmission pump do the rest? I always use this method when flushing PS systems on the E36 and E38.

I was wondering the same thing. OP, any insight?

[M I C H A E L]

Sorry to bump this topic, but i have an 01 740il and the transmission will not go into sport mode anymore, when you shift it into 4 the S does not light up anymore. The shudders have begun and one day none of the gear lights lit up on the dashboard, very strange.

Any idea? I'm going to try to do this flush as shown above.

but 4321 R N D P all illuminuate?

[racer2086]

I don't understand using the hand pump. I mean, I know you have to fill the pan as much as you can initially.

Is there no suction on that side? Can't one just hold the hose in the fresh fluid and let the transmission pump do the rest? I always use this method when flushing PS systems on the E36 and E38.

I was wondering the same thing. OP, any insight?

I'm sorry for not answering this. I didn't realize others had posted to the thread.

Yes the hand pump is necessary, because there is no suction on the input side. I hoped myself, but another member that did the flush said there was no suction. I tried, but it just blew out fluid without taking any back. So, you have to pump it back in by hand.

- - - Updated - - -

Sorry to bump this topic, but i have an 01 740il and the transmission will not go into sport mode anymore, when you shift it into 4 the S does not light up anymore. The shudders have begun and one day none of the gear lights lit up on the dashboard, very strange.

Any idea? I'm going to try to do this flush as shown above.

I believe you are facing a non-mechanical issue with the dash lights. There have been posts on here about members with similar issues. There was a different solution to that if I recall correctly. Hopefully a search can ahead light on that for you, as I just remember it from reading in passing.

[MaximusBKK]

I'm sorry for not answering this. I didn't realize others had posted to the thread.

Yes the hand pump is necessary, because there is no suction on the input side. I hoped myself, but another member that did the flush said there was no suction. I tried, but it just blew out fluid without taking any back. So, you have to pump it back in by hand.

Yes, I just realized why... The input line (trans to radiator) is pressurized due to the pump in the torque converter pumping the fluid through the line and to the radiator. The return line (radiator to trans) has no pump pulling fluid in, rather the fluid returns because of the vacuum created by the input line. When we are flushing the trans we have the lines disconnected, so that vacuum no longer exists. The fluid still pumps from the trans, but the return line now has nothing to "power" it and create suction without the vacuum pressure that was created when the system was connected.

[locknload]

I strongly suggest you do a "final fill" with the trans cold and the car level as recommended by zf. There really is no way to know exactly how much fluid you have (or don't have) in your tranny unless you fill it according to factory spec.

[M I C H A E L]

I strongly suggest you do a "final fill" with the trans cold and the car level as recommended by zf. There really is no way to know exactly how much fluid you have (or don't have) in your tranny unless you fill it according to factory spec.

not saying not to check it, as you should but trans failsafe would also come on if it detected low fluid levels.

[mgoods50]

THANKS racer2086!

I've been putting this off about as long as I can-- and MUST do it asap. I've got the whines now on the 740.

[Hueristic]

Thx for the write up and the link. how about an update. Is your shudder issue completely gone?

[racer2086]

Still shuddering. Not as bad, but still have it. My torque converter is seriously toast though. The Dr. Tranny Shudder fix would probably work great with the new fluid, but Valvoline said their fluid was compatible with my car and that my transmission wouldn't fail after the fluid change. They gave me a "sort of" guarantee where if my transmission did fail after the fluid change, they would request a fluid sample to make sure that I didn't put anything in it. Of course, I talked to them on the phone about that. Either way, I'm sure that's not valid for me anymore, because I've been driving for awhile without any issues.

[Sobek]

Great guide this one. I was going to do just a transmission pan fluid change this weekend, but now I'm seriously considering doing the full flush. I've only got 76k miles on it so I think it's in good order for a flush... How many litres (gallons) did you need to buy of trans fluid all up? I've got 10L, but I was thinking of getting another 5L or so as the specs state the whole transmission + TC holds 13 litres or so?

Also, having never taken off either the power steering or transmission cooling hoses, I'm assuming that when you do, there'll be a length of pipe protruding from the cooler still that you can mount the outlet clear hose onto?

[red740is]

Interesting write-up.. I used this method before but on a vehicle that had a dipstick tube for adding fluid. Was thinking if you wanted to make this a one-man operation, you could use a cheap modified garden pump sprayer to pressurize the fluid and hold a couple gals of fluid at a time.

As someone mentioned, you really do need to ensure the proper level via the fill plug.