E38 Transmission Flush DIY

[racer2086]

I used 5 gallons of fluid. I probably could have gotten away with closer to 4, but I flushed until the fluid looked really clean. I have most of a gallon left and sitting in my closet left over from topping the transmission up. Also, the clear tubing connected to the lines that were removed and hanging. It's hard to see because the lines didn't really hang below the bumper. Nothing connected to the cooler.

[Sobek]

Oh right, I thought you flushed it through the cooler to get whatever was in that out too... I'm surprised it only took you 5 gallons to flush it through, I would have thought you'd have to run the whole 10+ clean out. I really think I'll do this flush instead, just got to make sure my hand pump is up to it haha

[racer2086]

I didn't bother with the cooler. It holds a small amount and some of it leaks out when you remove the hoses. I don't think you can keep up with it using the hand pump unless you have a monster or something. I still had to turn the car off occasionally to top it up.

[Hueristic]

Does anyone know the size of the clear tubing to fit in the coolant connector for the fluid swap?

These



- - - Updated - - -

Guess who almost has a 5HP30 dipstick!



- - - Updated - - -

Guess who almost has a 5HP30 dipstick!

Yeah, I drink ALOT of coffee.

[locknload]

Ha, you drink a lot of BAD coffee.

I think the tubing was 1/2", maybe 5/16. It's only a few $ at HD so buy both & return the one you don't use. Get a hose clamp while you're there, you will need it regardless of how snug the tubing is.

[Hueristic]

Ha, you drink a lot of BAD coffee.

I think the tubing was 1/2", maybe 5/16. It's only a few $ at HD so buy both & return the one you don't use. Get a hose clamp while you're there, you will need it regardless of how snug the tubing is.

thx.

whats wrong with folgers?

[Penarol]

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.

I love the convenience of doing it like that but I need to ask a couple of things. First, not having it level doesn't affect the flush? and second, by the time you see the old fluid coming out of the hose, your tranny has already ran dry for a few seconds. Is that a concern? I just don't know enough about trannys. If you had it in neutral or park I would be more inclined to go with it but the fact that you're actually going through the gears as the fluid is being pumped out worries me. Any thoughts?

[racer2086]

You're not going through the gears while fluid is pumping. I did it in park. I just had a helper to start and stop the engine so I could catch up with my pumping. I started pumping in as the transmission was pumping out. You could probably pump before to get ahead a little, but you will have to stop to catch up. I can't remember if I just stopped part way through to be safe or if I saw a bubble. But you will probably see a bubble or two before anything runs dry. Transmission is still going strong at 197k miles as of this post (*knock on wood).

So long as you are aware of the risks...there are success and fail stories. Just remember, if you are doing a flush on a transmission that is already having trouble, this may be the nail in the coffin.

[ldotmurray]

Thanks for resurrecting this thread. I will drop and fill fluid and replace the filter and gasket but I don't know about a full flush. My transmission is smooth but it has a slight tranny whine.

[Hueristic]

Thanks for resurrecting this thread. I will drop and fill fluid and replace the filter and gasket but I don't know about a full flush. My transmission is smooth but it has a slight tranny whine.

Don't forget

item2.jpg

[Penarol]

Great job on the posting. By the looks on the pictures the upper hose on the connector would be the return (going to tranny) hose and the output (coming from tranny) would be the one on the bottom correct? Tks

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.

[racer2086]

Man, to be honest, I don't remember. But there is an easy way to tell.

Take the hoses off the cooler up front. Put a length of tubing on it and blow into the hose. The return line will be easy to blow into as it just goes back to the pan. The output line will not let you blow into it because it goes up into the pump/transmission (wherever it goes). That's the easiest way to tell.

[RandyBMC]

I am following these instructions to do the same on my '01 740iL. My cooler and hook ups are different. I will post some photos, but they look like some sort of quick disconnect hoses, so I can't just push on the tubing lines. I'm not sure yet if I will be able to do the flush now - I'll let you know what I come up with when I post photos, but this is significant for those of us with this set up.

[RandyBMC]

I ended up making some lines for flushing with old hard lines that had leaks at the hose connections - so if you don't have any of those laying around, I'm not sure how you could flush it. I thought about hooking up to the cooler for the pump input side (to keep filling the transmission with new fluid) and allow the outlet side to hang into the bucket freely. It would probably work that way but be really messy.



I'll try to post the photo of the lines and cooler. They are 5 and 6 (the first set off the transmission - the other set with o-rings is for the E39).

[Chamberlin]

I ended up making some lines for flushing with old hard lines that had leaks at the hose connections - so if you don't have any of those laying around, I'm not sure how you could flush it. I thought about hooking up to the cooler for the pump input side (to keep filling the transmission with new fluid) and allow the outlet side to hang into the bucket freely. It would probably work that way but be really messy. I'll try to post the photo of the lines and cooler. They are 5 and 6 (the first set off the transmission - the other set with o-rings is for the E39).

My '00 and '01 740i Sports have the later style trans cooler too, with those farking grey quick disconnects... I bought the 2000 Sport with a 'bad' transmission as the PO said, but just doing a fluid drain and fill (with new filter and pan cleanup of course) has brought the car back to life and it is drivable again. But now I know why the PO thought the tranny was bad.... it keeps puking out all its fluid from the quick connect lines to the cooler....

Is there any solution here to fix the quick connect leak, other than buying $300 worth of hoses, and re-doing the 40°C level fluid-fill procedure?

[racer2086]

There should be o-rings inside those quick disconnect fittings. You could probably take them out and match them up with new not-crushed-down o-rings to put back in there. That should take care of it.

[Chamberlin]

There should be o-rings inside those quick disconnect fittings. You could probably take them out and match them up with new not-crushed-down o-rings to put back in there. That should take care of it.

Oh yea, that would be great... I'll see if I can get them out with a pick and source the proper sizes and elastomers.
Thank you for your response!

[Chamberlin]

Looks like I'm back in business! Leaks seem to have been cured with new o-rings. I'm guessing the original o-rings were damaged when the previous owner took the car to Ammaco. They gave the PO a small vile of dark fluid to show him the ATF was 180k miles old. They likely got the sample from the quick disconnect hose, but jacked up the o-rings when re-installing. Each fitting takes two o-rings and the size I came up with was 14mm inner diameter, 2.5mm thick. Picked up 4 at the local O'Reillys and also bought the Dorman metric kit too which comes with 12 of the needed seals. I have two E38 sports right now and almost bought a rare Slate Green sport yesterday, so I figured I'd stock up on replacements. Thanks for the help! 4 bucks instead of $300!

[racer2086]

Awesome, glad it worked! Thanks for posting the sizes for future reference.

[M I C H A E L]

Well there's the problem... Aamco..

Sent from my VS995 using Tapatalk

[The Fish]

Thank you so much! I am planning on doing full maintenance on my first car 1998 (e38) and this helps me more than all the youtube videos I have been watching.

[jjc034]

Looks like I'm back in business! Leaks seem to have been cured with new o-rings. I'm guessing the original o-rings were damaged when the previous owner took the car to Ammaco. They gave the PO a small vile of dark fluid to show him the ATF was 180k miles old. They likely got the sample from the quick disconnect hose, but jacked up the o-rings when re-installing. Each fitting takes two o-rings and the size I came up with was 14mm inner diameter, 2.5mm thick. Picked up 4 at the local O'Reillys and also bought the Dorman metric kit too which comes with 12 of the needed seals. I have two E38 sports right now and almost bought a rare Slate Green sport yesterday, so I figured I'd stock up on replacements. Thanks for the help! 4 bucks instead of $300!

I actually got trans cooler hose from NAPA and replaced the quick connects with a simple hose clamp. Hasn't been leaking one but and was much cheaper than replacing the entire line. Just had to saw off fittings so I could get hose on metal portions.

Sent from my SM-G973U using Tapatalk

[Luckie]

Do I need to pump fluid through the hose?