Trans. Fluid Change?
 

1.What is the best fluid to use?]Brand & type]
2.What is the torque on the pan bolts?
3.What is the best way to get the fluid out of the pan without making a mess?

The best fluid would probably be Mobil synthetic (pricey). But really, any trans fluid that meets Dexron III should suffice... that and 30K change intervals.

The best way to drain is to open the pan drain bolt and let the fluid out before removing the pan.

Don't forget to drain the torque converter at the same time before refilling. Draining pan and torque converter will change 85% of the fluid.

Don't forget to buy a good quality trans service kit, gasket + filter. Widely available on line.

Steve

The pan does not have a drain bolt!
What is the torque on the pan bolts?

Think allen head bolt.

I think it may actually be 60 inch pounds which is 5 ft. pounds. Very light and even with a 1/4 " Ratchet.

Steve

There is a drain plug, but you have to crawl under there and look for it. There is now way not to make somewhat of a mess. One thing you should understand is that if your catch pan is on the ground and the car is up on jacks the draining fluid will splash all over the ground. I always try to get the pan up close to the bottom of the pan. But you will still slop some on the ground.

Sounds like new territory for you. Be careful when you wipe out pan and not leave lint or dirt behind.

Steve

Thanks for all of the help.I will do this next weekend.

Happened to me too.

Live and learn.

Jeff Pierce

The pan bolt torque may also be different based on the transmission model.

I have only done '90 300E and '92 300E. These have no spacers and the torque is 60 inch pounds. I bought and inch pound torque wrench for that purpose, cheap on e-Bay.

When I crawled under the '97 S320, I found the spacers. This automatically puts the correct compression on the gasket. I just tightened the bolts to what felt right with 1/4 ratchet.

Steve

Trans oil change
 

Did I miss something? I never changed the trans fluid in my '(97 ) C280, 100K miles and the trans worked fine. Think of it. Most trans changes only remove about 25 to 39% of the initial OE fluid. Trans are closed systems, so what happens to the synthetic fluid (other than a possible leak) that would require a fluid change? Oh, I also own a 30 year old Chevy Blazer. Never ( yet) changed the fluid. Have added, but the old Powerglide really works well. OK I must be a nut, right.

Wear particles begin to collect in the oil. This includes clutch material and metal fines, which contaminate the lubricant. The fluid can also shear and oxidize. Any lubricant is a consumable item.

Also, modern transmissions are designed to operate on that fine edge. You won't find vehicles today that are built with the robustness that the well-known Powerglide was built with.

I'm not saying your transmissions will grenade next week from lack of fluid changes, but changing fluid WILL help with transmission longevity. Peter, I believe your transmission uses the expensive synthetic fluid, which according to MB is considered fill-for-life. Even MB has recently taken a modified (and more sensible) approach by specifying a trans fluid change at 36K and consider the transmission good for life. Most DIYers here will tell you it should be changed every 50-80K if you plan on keeping the car for a long time. The manufacturer only cares if the car lasts through warranty.

420benz's transmission has a drain for the torque converter. Like I said earlier, when drained with the pan, this will get 85% of the fluid changed. There are relatively painless DIY methods to completely exchange transmission fluid on cars that lack a torque converter drain.

Hope Im not hijacking the thread too much but
a) would a 300 SEL (89) have a torque converter drain?
b) could you elaborated on the painless DIY methods?

Im a decent amateur mechanic but generally spent my time under small sports cars with manual transmissions, I want to treat my new additon right though.

Your 89 300 SEL probably has a torque converter drain plug. On mine it looks just like the transmission pan drain plug. It's just a matter of rotating the torque converter until it's at the bottom and recognizing it. Try searching, there's been discussion in the past about techniques.

Here's a writeup on the flush/exchange method I use for any car that doesn't have a torque converter drain:

1. Pull the transmission dipstick. Fresh fluid is translucent and cherry red. Some darkening is normal, but if it is reddish brown or mustard color and smells like burnt varnish, it is worn out.

2. Make sure the fluid is warm.

3. Remove all pan bolts except for the corners. Remove the bolt from the lowest corner, then loosen the other corner bolts a turn or two. Carefully pry the pan to break the gasket seal at the lowest corner. Drain mostly from this corner. With good technique you can avoid or at least minimize the red bath.

4. Remove pan. Inspect the pan before cleaning. A small amount of fine grey clutch dust is normal. However, if you find metal shavings, there has been transmission damage. Remove all old gasket material. Some rubber gaskets are reusable. Clean the pan and magnet with solvent and wipe dry so there is no harmful residue. Shop air can be used to clean the magnet. Hammer back any pan damage from previous overtightening.

5. (Optional) Drill hole in pan at low point and install a drain kit available from most auto supply houses. Make sure the kit protruding inside the pan doesn't interfere with anything on the transmission.

6. Replace filter.

7. Position gasket on pan. Some gaskets have four holes slightly smaller than the rest to allow four bolts through the pan and through these smaller holes to hold the four bolts and gasket in place.

8. Hand tighten pan bolts in a criss-cross pattern. After that, use a torque wrench to tighten bolts to proper ft-lbs as per manufacturer.

9. Refill the transmission using only the amount shown as “refill capacity” in the owners manual (or an equal amount that was drained), using the type of fluid specified for the vehicle.

10. You now have replaced the trans fluid and filter according to manufacturer’s requirements. Fluid is changed in the pan only.

You can stop here and go to Step 17 if you just wanted a regular drop-the-pan fluid change. For a complete exchange of the fluid (including transmission body and torquer converter) continue with the next steps.

11. Obtain the total system capacity of the vehicle from the manufacturer. Have this amount - plus a bit more - of fluid readily available.

12. Disconnect the oil cooler line from the oil cooler. Tickle the ignition to find the flow direction. Direct the stream of fluid toward a receptacle. It is better to use a clear length of hose with a shoplight laying next to it so you can see when all the old fluid has left the system.

13. Start the engine, let it idle to pump out old trans fluid until you start seeing air bubbles.

14. Stop the engine. Refill transmission through fill tube with fresh fluid - same amount as pumped out (usually about 2-3 quarts).

15. When either the fluid color brightens or the total capacity has been replaced, shut the engine off and re-attach the oil cooler line. All trans fluid has now been changed.

16. Button everything back up. Clean up the mess.

17. Recheck the fluid level. With the car on level ground, set the parking brake and the transmission in Park or Neutral. Let the engine idle for a few minutes. Shift the transmission through all detents, pausing momentarily at each position, before returning the lever to Park or Neutral. Check the fluid level again and check for leaks. Refill fluid so it is slightly undercharged. This way it can be properly checked and topped off after a long drive.

See the DIY article on the 722.6 tranny
 

It's exactly the same for the earlier models, except:
1. They have dipsticks
2. They use Dexron II/III
3. No song and dance about getting temp to 80C and filling to the rim (with Dr. Z's profit formula)

I plan to change the transmission fluid, filter and gasket on my 1988 560SL this spring. I assume that I currently have Dextron III, or whatever the MB dealer service gave the previous owner. The fluid looks clean and is not dark, but I do not know how long ago it was changed. I plan to drain the converter as well. as I understand the plug is accessible through the bell housing opening when the engine is rotated to have the plug down. I think the changing procedure is similar as Kestas describes, but I think I have a pan drain plug.

I plan to use a synthetic fluid that I purchased at Advance Auto when it was on a close out sale, it is BG Synthetic Transmission fluid, says on back that it meets Dextron III and lists several manufacturers including Mercedes. I was told that it was excellent stuff. Anybody have any experience with BG Tran fluid?

Any issues using sythetics in this transmission, or re-filling after non-synthetic fluid? Thanks.

You won't go wrong with a BG product.

Peter Fearing wrote, "Did I miss something? I never changed the trans fluid in my '(97 ) C280, 100K miles and the trans worked fine. Think of it. Most trans changes only remove about 25 to 39% of the initial OE fluid. Trans are closed systems, so what happens to the synthetic fluid (other than a possible leak) that would require a fluid change?"

If you drain your fluid it will be chocolate brown. Matter of fact, a friend of mine just did a trans service on his '98 SL. He reports chocolate brown fluid. He thinks he will either do future services at 30 K or 50K. My trans service at 109K, when I bought the S320, was not chocolate colored. However, the prior owner was smart and had it serviced at 65K.

So the fact that your transmission is fine now has nothing to do with whether it will fail next week. The 722.6 is an electronically controlled transmission. It's expensive to replace. A transmission service at a independent shop using the correct special MB fluid should be less than $250.

Not certain about your particular model, but the 25 to 39% figure you quote is dead wrong for MB with Torque Converter drain plugs. At some point they eliminated the TQ plugs, but my '97 S320 still has one. Transmissions may be closed, but the friction material does wear and gets suspended in the fluid. It then coats the bottom of the pan.

By the way, it's also a good idea to change the differential fluid, the coolant, and the power steering fluid, and brake fluid.

Steve

Personally, I hate the hassle of even thinking about doing a tran fluid change, and changing the filter etc. For the amount of time it takes to plan, gather stuff together, and actually do the job while reading instructions or paying super close attention not to screw up or anything....That's one job I'd rather pay mercedes to do. Its not due to often and its an affordable servicing job, why get ur self dirty..

New E class cars
 

Kestas: Thanks for the reply. Question. Do you think MB has solved the "quality" issue in its new cars? If so, what have they done? The owners manual that came with my '07, E550 has 506 pages and tells you very little about what or how to service, adjust or drive it. This manual is mostly a "marketing" program. Hey, just because we own, buy and drive these luxury cars does'nt mean we are'nt interested in getting our hands dirty. This happens to me regularly since I'm a surgeon.

Peter, you're a rare breed. Most of us are used car buyers. It's also rare to find a surgeon who wrenches.

I could write volumes on the subject of quality and what has happened to the auto industry. The reasons you see little written on maintenance in the owners manual is that cars like the E550 have gotten so complex that the average person has little interest in having a hand in maintenance, nor does the manufacturer (for various reasons) want the average person working on thier cars.

On the subject of quality, the parts on a car are built much more consistently than in the past. Unfortunately, the modern automobile has more parts on it than ever before. And this goes double for Mercedes, which believes in loading the car with all kinds of gizmos. This added complexity of parts offsets anything we've gained with the consistency of parts.

Another factor is that nowadays parts are being manufactured at the "fine edge" of just being able to perform, to get the job done, and no more. Robustness has gone out the door. Ever since the 60s we've seen robustness designed out of an automobile. I work in automotive manufacturing and rub elbows with automotive engineers on a daily basis. They all say the same thing, that they are squeezed by the auto manufacturers to get the part price down. The auto manufacturers even jump in and show you where you can take robustness (and quality) out of a part.

MB is no different. Ever since Lexus became a contender of luxury imports, MB has been looking to get their manufacturing costs down to stay competitive. Regardless of what they've recently announced, they will never solve the quality issues beyond what they have already been doing. Their announcement was nothing more than palaver to appease the masses worried about MB quality going downhill. They will continue to manufacture cars with the same poor quality as they can get away with. After all, the competition isn't that much better. So don't expect to see any improvements soon.

The other side of the coin is that the average car buyer wants (and expects) all the frills and gizmos that he feels entitled to in a luxury car. And he wants to pay little for it. So I blame much of this quality issue on the consumer. They get what they demand. Nobody walks into a dealer to appraise a car on the ease of repair.

If I was to start the Kestas Motor Manufacturing Co., and build quality cars with little more than the simple "luxury" amenities and ease of repair found in your 1970s automobile, it would fall flat on it back, because nobody wants such a car. Just do some "market research" and ask your friends what they look for in a new car. Their answers tell all... A/C, auto, ps, pb, and AM/FM/CD just doesn't cut it anymore with the average new car buyer.

I remember twenty years ago my colleagues told me that Mercedes was headed in a direction that they now have with their quality. They said that if they put their design and development efforts into increasing the quality of each existing component instead of adding new parts on a car, they'd have one heck of a grand automobile.

No use lamenting
 

It is what it is. MB still likes making good cars, they just have to be able to sell them as well.

I think another point, however, is that MB was historically a company of mechanical engineers, and they have been lagging on the electrical/electronic side.

Take a look at the 201 and 124, which sold all the way up to 1995: they had one of the finest shift interlock cables in the world, and the glorious panoramic wiper mechanism, and the ingenious snaky sunroof cable. If it was mechanical, MB could do the best job around - including sheet metal quality. On the electrical side they were nothing fancy, if not backwards in some cases. Look at the engine harness debacle - who would let that go on in production? And the piss-poor AM radio reception that continues to this day. What EE would put his stamp on radios like that?
Maybe this is all logical since: 1. the Schwobs have historically been great cuckoo-clock builders and 2. Germans historically have scoffed at anything that distracts you from going 250 on the Autobahn (e.g drinking coffee). The electronics gurus have come from elsewhere in the world.

MB Quality
 

Kestas: Thanks for your reply to my inquiary regarding quality. I can't say I agree 100% with what you say about the car industry what with consumer law suits and liability issues. On the other hand I know from experience that as a surgeon, quality is job # 1. In other words I and my fellow medical people are doing work that is second to none. Oh, I know that most folks feel that medical charges are way too high but I and others spend time each year in a 3rd world country doing work that folks really need thus we have to cover some costs. You probably don't regard doctors as "the best" any more. We try. It does seem unusual however that we are able to drive these "luxury" cars but I can't help it when my nurse gives me my pay check and it is quite a large sum. I just think MB is making a big mistake by lowering quality just to compete. Maybe I will work on one of their bottom line guys and make a minor error. No. Just kidding. I could never do it.

Tom, that's why the japanese are so much more successful with car manufacturing and build quality. So much of a car's engineering is made up electricals and electronics nowadays. The japaese have historically dominated the electronics market and have adapted much of this technology to automotive design. They have fewer electrical gremlins in their vehicles while everyone else is trying to play catchup.

Peter, I'm glad you take pride in your work. I do too, in my profession as well as wrenching on cars for myself, family, or friends. Unfortunately, I'm squeezed at work to add expedience to my quality. (Interestingly, when I was a junior engineer, it was the other way around, and I was asked to add quality to my expedience... you just can't win!) I know that doctors are squeezed as well.

But back to MBs. After owning my E320 for five years, I can honestly say I've never owned a car that needed so many repairs. It's all the gizmos on my car that keep breaking down. It's reached a point where I almost hate to drive the car, knowing that something else will break in a short while. There are many days that I sincerely believe my mother's Mercury Sable is a better car than my E320.

MB Quality
 

What I do has to be perfect. Everytime. No excuses. Now you folks have me worried that less than perfect is OK due to competition. I think that the people that run an important car company had better make "perfect" cars. Thus I think the MB guys must have a clue that if their cars are prone to breakage they have no other choice than to ramp it up. I expect my '07, E550 to be, well perfect. In achieving this my only worry is dealer service. I worry that 18/20 year olds don't know what or how to service a complicated machine such as these new German autos. Call me naive, but I refer back to what I do every day and you can be absolutly positive that I will not make a mistake, not so far and that is about 22 years.

I too have same worries... on both issues.

I worry about the cars built today bacause I see how components are designed. I ask the design engineers why parts aren't robust and I get the answer I posted above, that the manufacturers don't want to pay the price premium. They only want it "good enough" and for certain design features to only last through warranty.

Cars - especially MBs - are so complicated that sometimes the technician has no choice but to throw up their hands and say "I give up!".

I too thought I was buying a quality car when I bought my E320. I was naive. I can only hope the best for your ownership of the E550. You have no worries if you're only planning to own it through the warranty period.

The complexity, lack of quality, and difficulty of repair have given Mercedes vehicles low residual value during resale. Ironically, this is also the reason I could afford my E320 when I bought it as a 7 year old car. They cost $75-80K when new!

sorry to interrupt this intellectual discourse...

my question here is rather simple - my W202 has a normal Japanese/American AT style dip stick hole with a fat neck "seemingly" designed for filling the tranny up with fluid. But According to my friend there is NO maintenance period on these auto trannies from Mercedes. The thing I want to know is, if the fluid does look chocolaty, will a minute-lube style flush (tubes connected to drain plug hole and dipstick neck, then pump fresh fluid in to displace the old chocolaty stuff) is that still a "proper" way to flush a Mercedes transmission???