panason1c
MB Enthusiast
For what it's worth, i dont think that travelling in 4th for however long would cause any problems whatsoever (apart from excessive fuel consumption), i do, however, think that your problem was entirely due to the probability of an overfilled 'box.
The correct oil level is critical in the 722.6 'box as is using ONLY the MB oil.
{Edit}...Just found the article below, makes interesting reading....
Filled for life?
The 722.6 Automatic Transmission uses a special oil and is said to be filled for life. The oil can only be purchased through the Mercedes-Benz dealer using part number 001-989-21-03-10. A 722.6 holds about 9.3 liters and the fluid is sold by the liter. Checking the fluid is accomplished by breaking off the red locking seal located at the dip stick. the lock is replaced after the oil is checked. Use part number 140-991-00-55 for a new lock. There is no dip stick to check the ATF. You need a special tool to check the fluid on all 722.6 transmissions, part number 140-589-15-21-00. The oil level is a critical factor in transmission shifting. See Service Information 27A95105 for details. When you refill, or check thetransmission fluid level make sure that you check the level with the special tool and at the correct temperature. The latest information from Germany is that we should fill the oil to the MAX line. Not overfilled, just maxed out. This is said to improve shift quality. At normal level it is possible for the oil to form air bubbles. The increased level helps to minimize this. You might want to remember to try this on customer complaints involving shift quality before you replace any component. Along with setting the adaptation you would be surprised to see how much of an improvement you will see.
The Automatic Transmission fluid is said to be filled for life. We never specified who's life. (Yes, they actually wrote that in this!-DG) The transmission control module contains a program that keeps a running count of the "calculated" cndition of the ATF oil. (Note from Gilly-I believe this was deleted from the modules right around 2001-2002, not there anymore-DG) The factors that affect the oil are time and temperature. The counter is incremented with engine running time and incremented greater with higher ATF temperatures. The Hand-Held Tester (now SDS-DG) displays a numerical value that represents the value of the calculation. At some given point in time Germany will tell us (still waiting, evidently-DG) which number means its time to change the oil. For now there is no service interval for the ATF oil. If you replace a transmission you should re-set the counter back to zero to account for the new oil. If you are doing internal work and you are replacing the oil you should also re-set the counter. It is acceptable to drain the oil out into a clean container and reuse it, provided it was collected using the MB filter funnel. Remember to flush the converter and kines before installing the new transmission. You should also replace the converter if the transmission was HEAVILY contaminated with metal. Make sure you return the converter with the transmission to warranty. Fine metal particles in the bottom of the pan are allowed. (I think what they mean here is that fine metal particles are considered an "acceptable" condition, do NOT replace transmission, as you will see if you read on:-DG)
The Color of Money:
We have been conditioned to judge the quality of the transmission fluid based solely on it's color and smell. We have no way of judging the frictional quality. The rules have changed. (didn't Iaccoca say that too?-DG) The bright red color that we are all used to seeing may not be what you see when you look at the ATF in a 722.6. The reasons that the oil looks differently are as follows:
1) The oil may appear dark red due to the graphite material that the friction discs contain. This does not change the characteristics of the oil. Do not change the oil or transmission if the oil appears dark red or even if it has a yellowish tint to it. The color will change with time and temperature. As of 10/97, the manufacturer of the oil has agreed to put more red particles in the oil.
2) If a copper color is seen in the oil pan the bushings of the front or rear planetary gear set may be in the process of wearing out. Inspect the bushings and if they are defective replace the complete transmission. If they are not defective, then the transmission is repairable.
3) If a silver color is present in the oil it may be a clutch and steels moving up and down on the hub as they are being applied. This is normal! Use your best judgement here. If the particles are fine they should not cause problems as they will be trapped in the filter. The fluid could be drained, including the torque converter, and the lines flushed and the valve body should be disassembled and cleaned, replace the filter of course. This usually takes care of the problem. If you take the time to inspect and clean each slide valve for ease of movement and base position you will have a better valve body than a new one from spare parts. In more severe cases where the particles are large, then something is in the process of self destruction and the transmission should be either replaced or repaired. Don't forget to check the electrical solenoid valves. Shine a light through the top of it and see if it "leaks". If you drop the transmission oil pan (I think they mean "remove the pan"-DG) and you find yourself feeling like a miner panning for silver, or knee deep in a graphite colored mud, then it's time for a new transmission. You may have noticed that the new pans are painted black on the inside. The metal particles show up better against a black background as opposed to the previous unpainted silver pan. You must get used to seeing some metal in the bottom of the the pan, with this transmission this is normal.
4) Smell the oil. You know by now what burnt oil smells like. If it looks burnt, and it smells burnt, then its burnt.
Example: Try looking at the adaptation values for K3. If the numbers are high, then you have a K3 problem. If the customer is complaining about shift quality going in and out of third gear, repair K3.
5) Make sure you understand the complaint before you disassemble the transmission. Use the HHT (SDS now-DG) adaptation screen values along with the shift application chart to see which shift members are applied during your customer complaint so you will know where to concentrate your efforts when you disassemble. Remember to disassemble the transmission like a surgeon, you need to observe the condition of seals, rings, c-clips and shims as well as being aware of the potential for missing parts.
Repair or Replace:
Use the transmission oil pan as an indicator when deciding to repair or replace the 722.6 transmission.
The following pictures (sorry folks, I'm transcribing the written part only, no pictures-DG) are for reference as to which transmissions should be replaced and which should be repaired.
(picture shows a black pan with some small "dots" here and there-DG) This is a normal oil pan for a 722.6. The fine particles are normal. Do not replace this transmission.
(can't tell what's "wrong" with this picture-DG) The brass colored particles may be a sign of a bushing problem. This transmission may be repaired.
(can't tell by the next picture either what the problem is supposed to be, rotten copies!-DG) The metallic sludge indicates that there is a major mechanical problem. This transmission would probably cost more to repair than to replace.
(This picture you can see obvious copious amounts of metal shavings, a pretty good coating of it-DG) This picture also indicates internal damage has been done. This transmission would be replaced (as well as the TC and flushing lines and cooler, etc-DG).
The correct oil level is critical in the 722.6 'box as is using ONLY the MB oil.
{Edit}...Just found the article below, makes interesting reading....
Filled for life?
The 722.6 Automatic Transmission uses a special oil and is said to be filled for life. The oil can only be purchased through the Mercedes-Benz dealer using part number 001-989-21-03-10. A 722.6 holds about 9.3 liters and the fluid is sold by the liter. Checking the fluid is accomplished by breaking off the red locking seal located at the dip stick. the lock is replaced after the oil is checked. Use part number 140-991-00-55 for a new lock. There is no dip stick to check the ATF. You need a special tool to check the fluid on all 722.6 transmissions, part number 140-589-15-21-00. The oil level is a critical factor in transmission shifting. See Service Information 27A95105 for details. When you refill, or check thetransmission fluid level make sure that you check the level with the special tool and at the correct temperature. The latest information from Germany is that we should fill the oil to the MAX line. Not overfilled, just maxed out. This is said to improve shift quality. At normal level it is possible for the oil to form air bubbles. The increased level helps to minimize this. You might want to remember to try this on customer complaints involving shift quality before you replace any component. Along with setting the adaptation you would be surprised to see how much of an improvement you will see.
The Automatic Transmission fluid is said to be filled for life. We never specified who's life. (Yes, they actually wrote that in this!-DG) The transmission control module contains a program that keeps a running count of the "calculated" cndition of the ATF oil. (Note from Gilly-I believe this was deleted from the modules right around 2001-2002, not there anymore-DG) The factors that affect the oil are time and temperature. The counter is incremented with engine running time and incremented greater with higher ATF temperatures. The Hand-Held Tester (now SDS-DG) displays a numerical value that represents the value of the calculation. At some given point in time Germany will tell us (still waiting, evidently-DG) which number means its time to change the oil. For now there is no service interval for the ATF oil. If you replace a transmission you should re-set the counter back to zero to account for the new oil. If you are doing internal work and you are replacing the oil you should also re-set the counter. It is acceptable to drain the oil out into a clean container and reuse it, provided it was collected using the MB filter funnel. Remember to flush the converter and kines before installing the new transmission. You should also replace the converter if the transmission was HEAVILY contaminated with metal. Make sure you return the converter with the transmission to warranty. Fine metal particles in the bottom of the pan are allowed. (I think what they mean here is that fine metal particles are considered an "acceptable" condition, do NOT replace transmission, as you will see if you read on:-DG)
The Color of Money:
We have been conditioned to judge the quality of the transmission fluid based solely on it's color and smell. We have no way of judging the frictional quality. The rules have changed. (didn't Iaccoca say that too?-DG) The bright red color that we are all used to seeing may not be what you see when you look at the ATF in a 722.6. The reasons that the oil looks differently are as follows:
1) The oil may appear dark red due to the graphite material that the friction discs contain. This does not change the characteristics of the oil. Do not change the oil or transmission if the oil appears dark red or even if it has a yellowish tint to it. The color will change with time and temperature. As of 10/97, the manufacturer of the oil has agreed to put more red particles in the oil.
2) If a copper color is seen in the oil pan the bushings of the front or rear planetary gear set may be in the process of wearing out. Inspect the bushings and if they are defective replace the complete transmission. If they are not defective, then the transmission is repairable.
3) If a silver color is present in the oil it may be a clutch and steels moving up and down on the hub as they are being applied. This is normal! Use your best judgement here. If the particles are fine they should not cause problems as they will be trapped in the filter. The fluid could be drained, including the torque converter, and the lines flushed and the valve body should be disassembled and cleaned, replace the filter of course. This usually takes care of the problem. If you take the time to inspect and clean each slide valve for ease of movement and base position you will have a better valve body than a new one from spare parts. In more severe cases where the particles are large, then something is in the process of self destruction and the transmission should be either replaced or repaired. Don't forget to check the electrical solenoid valves. Shine a light through the top of it and see if it "leaks". If you drop the transmission oil pan (I think they mean "remove the pan"-DG) and you find yourself feeling like a miner panning for silver, or knee deep in a graphite colored mud, then it's time for a new transmission. You may have noticed that the new pans are painted black on the inside. The metal particles show up better against a black background as opposed to the previous unpainted silver pan. You must get used to seeing some metal in the bottom of the the pan, with this transmission this is normal.
4) Smell the oil. You know by now what burnt oil smells like. If it looks burnt, and it smells burnt, then its burnt.
Example: Try looking at the adaptation values for K3. If the numbers are high, then you have a K3 problem. If the customer is complaining about shift quality going in and out of third gear, repair K3.
5) Make sure you understand the complaint before you disassemble the transmission. Use the HHT (SDS now-DG) adaptation screen values along with the shift application chart to see which shift members are applied during your customer complaint so you will know where to concentrate your efforts when you disassemble. Remember to disassemble the transmission like a surgeon, you need to observe the condition of seals, rings, c-clips and shims as well as being aware of the potential for missing parts.
Repair or Replace:
Use the transmission oil pan as an indicator when deciding to repair or replace the 722.6 transmission.
The following pictures (sorry folks, I'm transcribing the written part only, no pictures-DG) are for reference as to which transmissions should be replaced and which should be repaired.
(picture shows a black pan with some small "dots" here and there-DG) This is a normal oil pan for a 722.6. The fine particles are normal. Do not replace this transmission.
(can't tell what's "wrong" with this picture-DG) The brass colored particles may be a sign of a bushing problem. This transmission may be repaired.
(can't tell by the next picture either what the problem is supposed to be, rotten copies!-DG) The metallic sludge indicates that there is a major mechanical problem. This transmission would probably cost more to repair than to replace.
(This picture you can see obvious copious amounts of metal shavings, a pretty good coating of it-DG) This picture also indicates internal damage has been done. This transmission would be replaced (as well as the TC and flushing lines and cooler, etc-DG).
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and a bad one at that 
I have no idea what they were trying to achieve in the first place 
