Transmission fluid level puzzle -- '96 E300D (W210) - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 11-11-2007, 04:27 PM

I am having a hard time getting the transmission fluid level in our new-to-us 1996 E300D adjusted to the correct level. Additionally, after the car has been driven and allowed to sit and cool off in the garage for a few hours, a spoonful or two of fluid is burped onto the floor from the area of the torque converter.

I have checked the fluid level many times. I had it set to the upper level (engine hot and idling) but noticed that when cold and not running, the level was way high on the dipstick -- up towards the first set of s-bends. I sucked out a pint of fluid with my Miti-vac and now the fluid barely registers on the dipstick when hot, but the tranny still burped fluid on the floor a couple of hours ago after I ran some errands.

The amount of fluid in the "burp" does not seem to depend on the miles driven -- about the same amount for a few miles around town or the 250 miles to the Diesel Drive in Sacramento yesterday. The fluid is apparently not being leaked in large amount during driving -- I noticed no difference in level when I returned from Sacramento. If there were a serious leak, it should have done something to the level during 250 miles of freeway driving.

The 1996 E300D still used the older 4-speed transmission (722.438), similar to the 722.357 transmission in the W124 300D and even the late versions of the W123 300D (722.416). [Source: EPC] These units are not electronic and use regular "Dexron" type fluid. The engine and transmission are both original and have 248,000 miles on them.

I changed the fluid from whatever came with the car to Mobil-1 synthetic. If the transmission were over-full, I could see it losing a bit as the transmission cools down and the fluid collects in the pan. That should have stopped when I lowered the level, however, so I am puzzled. Any suggestions?

Jeremy

junqueyardjim · #2 11-11-2007, 05:37 PM

But the only correct reading on that transmission is hot, with the transmission in park or neutral after running the selector through the shift range. Don't worry about what it reads cold. I hope you can come up with a good answer for that burping.

TMAllison · #3 11-11-2007, 06:30 PM

Yours should be the same as my 722.608 as far as procedures go. Fluid level should be checked hot (trans fluid at 80c, NOT engine temp) and should be filled to the upper end of the 80C range when idling in park. A 20 mile ride should ensure is at full operating temp if you dont have an IR thermometer to measure at the pan.

Engine off will appear drastically overfilled when checked hot or cold (fluid is all in the pan rather than being pumped around).

Mine took 7.5L. I carefully collected drained oil and measured in addition to using the dip stick to fine tune. Confirm using your OM because different models do have different factory fills.

Jeremy5848 · #4 11-11-2007, 07:20 PM

Thanks for the "engine off" comment -- the books never mention it.

After draining both the transmission and the torque converter, I had about 6 quarts of old fluid. About half came from the torque converter. Therefore, I said to myself, I can put 6 quarts back in. I was surprised that at about 5 quarts, the new fluid backed up the dipstick tube into my funnel and also came out of a vent (I suppose) in the tranny, all over the floor (about a pint, I suppose). I realized that I should have poured in only about 4 quarts and then started the engine to move some of the fluid to the torque converter.

I started the engine, let it idle for a minute, backed out of the garage so I could clean up the mess on the floor. I checked the fluid level at idle (engine/tranny still cold) and the fluid was off of the bottom of the dipstick.

Then I carefully finished adding fluid to the transmission, stopping after every half-pint or so to check the level. When I had it in the lower (cold) section of the dipstick, I quit adding.

Since then, every time the car has been driven, it has burped a little fluid onto the floor. The fluid comes from the area where there is a perforated cover over the torque converter. It doesn't do it immediately after stopping but if I check back in a couple of hours, it'll be there. Of course I'm afraid that either my overfilling or my use of synthetic ATF after almost 250,000 miles of non-synthetic oil may have damaged a seal.

This morning (cold transmission, engine not running), when I found that the fluid level was high on the dipstick, I sucked out a pint with my Miti-vac. After that, the fluid level was at the low mark hot and idling. Based on your explanation, I should not have extracted the fluid. I'll put it back.

Remaining is the 'burp' question.

Jeremy

TMAllison · #5 11-11-2007, 07:38 PM

Didnt answer the burp question cause havent heard that one before.

Perhaps is indeed air somewhere because of being initially overfilled before starting up to pump some to the TC? Have you tried shifting from R to D 10 or 20 times???

I put in 3L then started it breifly and shifted to R and D once, then shut down and added 3 more, started again, shifted again a couple of times and then checked level and began slowly adding. Based on what I removed (no leaks or spillage) I knew would take more than 7L.

Parrot of Doom · #6 11-11-2007, 08:40 PM

Take the car for a 20 minute drive, return home, and with the gearbox in park and the engine running, measure the level. Thats how its done.

Jeremy5848 · #7 11-12-2007, 08:33 PM

The burp continues. Looks like I have some options:

1. Add stop-leak (something with "miracle" in the name, as Click and Clack say) to the Mobil-1 synthetic ATF now in the tranny, hope the leak stops.

2. Drain the Mobil-1, go back to standard ATF, hope the leak stops.

3. Add stop-leak to the standard ATF, hope the leak stops.

4. Ignore the leak, check the level occasionally and top off as necessary, hope the leak stops.

5. Replace the leaking seal (the "E-Class Owner's Bible" says on p.201 that a problem with these transmichigans can be "fluid leaks from the front pump area"). I presume that replacing the input shaft seal requires pulling the tranny; with 248,000 miles on the odometer, it would be wise to install a rebuilt or rebuild the existing one. Obviously expensive and a last resort.

Comments?

Jeremy

TMAllison · #8 11-12-2007, 08:43 PM

#4 first until you can positively confirm where/why it is leaking.

Then revert to #2 as Dex III is cheap, followed by #3, then #4, then #5.

Parrot of Doom · #9 11-13-2007, 06:26 AM

I would never add any 'anti-leak' compounds to a fluid in a car.

Your best bet, although you may not like it, is to repair the leak.

nhdoc · #10 11-13-2007, 06:55 AM

I'll ask a silly question, but why do you describe the leak as a "burp" and not just a leak? Is it possible that your TC drain is leaking? Did you remove the old seal ring and replace it with a new one when you drained it?

I'd be highly suspect of that before I would conclude that something else went wrong coincidentally just at the time you did your service on it.

Jeremy5848 · #11 11-13-2007, 11:41 AM

Quote:

Originally Posted by nhdoc

I'll ask a silly question, but why do you describe the leak as a "burp" and not just a leak? Is it possible that your TC drain is leaking? Did you remove the old seal ring and replace it with a new one when you drained it?

I'd be highly suspect of that before I would conclude that something else went wrong coincidentally just at the time you did your service on it.

Good questions. The reason I call it a "burp" and not a leak--
(a) when the car is driven into the garage and parked, there is no immediate flow or drip of oil. You have to wait an hour or two and come back to find a couple of spoonsful of ATF on the floor. If I had a time-lapse camera, I'd set it up to record the process.
(b) once the 'burp' is over, there is no more until "next time."

I did not replace the copper washer on the TC drain plug. I inspected it and it looked to be capable of sealing again. Since I didn't have a new one anyway, I re-used it. Given the position of the drain (on the outside circumference of the TC), I would think that a leak would result in a loss of fluid proportional to the number of miles driven. This does not appear to be so -- the size of the burp is about the same after 10 miles or 100 miles.

I agree that something I did during the service caused the problem. I am thinking now that the burp is some fluid which, in draining back to the transmission pan after the engine is stopped, leaks out somewhere and makes a little puddle on the floor.

After 248000 miles on standard ATF (changed every 60000 miles, according to the service records), putting Mobil-1 synthetic ATF in the transmission may have something to do with it.

Jeremy

nhdoc · #12 11-13-2007, 12:51 PM

I'd say it is possible for the drain plug to leak and while the TC is spinning it sends the fluid flying around the enclosure which settles over time after you park it and drips onto the floor...for the heck of it you should examine the drain plug to see if it looks like it is the source...I'd bet a nickel it is.

Jeremy5848 · #13 11-28-2007, 12:57 AM

Quote:

Originally Posted by nhdoc

I'd say it is possible for the drain plug to leak and while the TC is spinning it sends the fluid flying around the enclosure which settles over time after you park it and drips onto the floor...for the heck of it you should examine the drain plug to see if it looks like it is the source...I'd bet a nickel it is.

It's not the TC drain. Wish it were.

I removed the Mobil-1 synthetic ATF, replaced it with a non-synthetic Pennzoil ATF (it was what the parts store was selling). Both drain plugs got new copper washers. The leak has continued and appears to be getting worse. I can watch it drip now as the engine idles (belly pans off, of course). About a drop a second, fluid level was at the minimum mark so it has lost some fluid in the last week or so.

Today I added a 12 ounce can of Trans-X stop-leak product to the transmission. I don't expect it to work but haven't much to lose at this point. Since the car has 249000 miles on it, I expected to have to R&R the transmission at some point, just not so soon after making the purchase. I should never have touched the transmission in the first place, oh well.

The dealer's mechanic reported a transmission leak in the front pump area when the car had 186000 miles on it, four years ago. No indication that anything was done about it but perhaps some sealer was added -- the belly pan was dry when I removed it a couple of weeks ago.

Given the miles on the transmission, I don't see any viable option (if the stop leak doesn't work) to replacing the transmission with a rebuilt, expensive though that may be ($3000?). Although the transmission is working fine in spite of the leak, there's no way to tell how much life is left in the various components. If I had my own shop and was experienced in pulling and opening up transmissions, I might try to replace just the seals, but that's not a job I would care to do for the first time with no help and no experience.

I need to make a decision and act soon -- we want to take the car on our annual Christmas visit to the family.

Jeremy

nhdoc · #14 11-28-2007, 06:35 AM

Maybe you're right that the old fill had some sealer in it and your replacement of the fluid started the leak over again. If you're luck the new sealer will work...we'll keep our fingers crossed for you, let us know how it does.

In the mean time you might just try calling around to a couple of local transmission shops to get their advice. I don't think I would abandon an older tranny if all it needed was a new seal. Maybe you will find a shop that would do the job for a reasonable price...one who was looking for work this time of year. It certainly would be much cheaper to fix the leak than replace it - probably on the order of half or less.

Jeremy5848 · #15 11-29-2007, 03:24 PM

One of the downsides to living in a place that does not experience a real winter is that there is no "off season" for some things including auto mechanics. (I was raised in northern Wisconsin and have several sets of ancestors who lived in NH in the early-to-mid 1800s so I know what winter is.)

Consequently, none of the local mechanics seem to be very hungry. The transmission R&R process would cost a minimum of $500 and neither my mechanic nor the transmission shop are really eager to just replace the leaking seals. While doing a complete rebuild is to their financial advantage, I can certainly understand the risks (to me) if they don't.

Although the pan had almost no dirt in the bottom when I removed it to change the filter (just a thin haze, from the clutch packs, I suppose), previous owners had changed the fluid and filter regularly so there's no knowing how much wear has been cleaned out of the pan in the past. There might be many miles left or only a few and I don't need to find out in Battle Mountain, Nevada (I-80 enroute to Salt Lake City) at 5pm on a cold and snowy Saturday evening. We've been there at -35F; I don't recommend it.

Since we plan to keep the car as long as possible (spring perches and all), the cost will be amortized over a lot of miles.

Jeremy