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  #16  
Old 12-11-2016, 09:44 PM
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Quote:
Originally Posted by 97 SL320 View Post
Are you able to see live trans data? If so, look at requested gear , actual gear and shifter position.

If you are looking for codes in the engine computer, they won't be there , need to get into the trans computer with the 38 pin under hood connector ( at least on 1997 cars, however at some point in later years, everything went through the under dash OBD 2 )
I am not sure how to view live trans data. Dave has an OBD2 scanner, will that work?
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  #17  
Old 12-12-2016, 03:31 AM
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Usually the transmission is designed to hold onto first gear longer when cold to assist warming up, could it be this mechanism is faulty in some way?
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1996 Mercedes S124 E300TD - 129k - rolling restoration project -

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  #18  
Old 12-12-2016, 10:27 AM
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Could be a Maf sensor fault,
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  #19  
Old 12-12-2016, 07:16 PM
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Quote:
Originally Posted by 97 SL320 View Post
Are you able to see live trans data? If so, look at requested gear , actual gear and shifter position.

If you are looking for codes in the engine computer, they won't be there , need to get into the trans computer with the 38 pin under hood connector ( at least on 1997 cars, however at some point in later years, everything went through the under dash OBD 2 )
^^

This

the above is how I determined the gear lever position sensor fault in the post mentioned above. I used carsoft to see it, the first move showed it then it got lost and the transmission just held onto first gear till the thing warmed up.
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  #20  
Old 12-12-2016, 09:27 PM
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Quote:
Originally Posted by ROLLGUY View Post
I am not sure how to view live trans data. Dave has an OBD2 scanner, will that work?
Only way to tell is to hook up and scroll through the options. As I said in a prior post, not everything can be viewed from the under dash OBD2 port on older cars, see if you have a 38 pin under hood connector.
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  #21  
Old 01-24-2017, 10:22 PM
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UPDATE

Well, the problem is still there, and I have not been paid for the work yet. Dave has just been warming the car up for a while before going to work, or parking it in the garage when available. I got a suggestion from Marc at Sun Valley Mercedes transmissions today, and it sounds promising. Marc had the same problem once, and tried everything to fix it. He told me how he diagnosed the problem. What he did, was to leave the car in the cold, and then use a hair drier to heat the area around the shifter. He found that the switch was sticking, thereby giving the trans computer a wrong signal. Once the cab was heated (or the area around the shifter heated to test his theory), the car shifted like it should. He replaced the entire shifter assembly (evidently the switch is hard to replace, or not available), and that fixed the problem. Fortunately Dave has an identical parts car. I will replace the shifter if that turns out to be the problem. I feel bad for having replaced the conductor plate (about $500 parts and labor), and that not being the problem. I probably should have called Marc first, rather than throw parts at it.........Rich

EDIT: Reading back, this was suggested but I must have missed it. I guess not having the proper (expensive) test equipment threw me off. A hair drier is not that expensive......Rich

Last edited by ROLLGUY; 01-24-2017 at 10:35 PM.
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  #22  
Old 01-24-2017, 11:14 PM
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Glad you found the problem.

For anyone who follows this, the range recognition switch is a replaceable part within the shifter.

You have to remove the shifter and disassemble it to remove the switch cartridge.

Before buying a new one try popping the switch casing open and clean the circuit board with alcohol. When you move the shift handle, you are sliding contact pads across a circuit board. Spilled liquids down the shifter wreak havoc with this system.

The transmission mechanically detects the P, R, N, and D positions by motion of the shaft. The 4-3-2-1 and the S/W switch are only digital inputs to the TCM. Once the handle is pulled from D to 4 the handle is decoupled from the transmission shaft (which stays in D) and the handle continues to move the slider down the circuit board.
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2014 ML350 Bluetec (wife's DD)
2008 E320 Bluetec (my DD)
2008 ML320 CDI (Older son's college DD)
1998 E300DT (Younger son's college DD)
1987 300TD sold to vstech
----------
gone but living on
1983 240D (body to greazzer, engine to t walgamuth)
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  #23  
Old 01-25-2017, 12:46 AM
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Quote:
Originally Posted by jay_bob View Post
Glad you found the problem.

For anyone who follows this, the range recognition switch is a replaceable part within the shifter.

You have to remove the shifter and disassemble it to remove the switch cartridge.

Before buying a new one try popping the switch casing open and clean the circuit board with alcohol. When you move the shift handle, you are sliding contact pads across a circuit board. Spilled liquids down the shifter wreak havoc with this system.

The transmission mechanically detects the P, R, N, and D positions by motion of the shaft. The 4-3-2-1 and the S/W switch are only digital inputs to the TCM. Once the handle is pulled from D to 4 the handle is decoupled from the transmission shaft (which stays in D) and the handle continues to move the slider down the circuit board.
I am not sure that is the problem yet, I should know tomorrow. I was told it is not an easy job to replace the switch, so I will use the entire assembly from the parts car if in fact the switch is bad.
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  #24  
Old 01-25-2017, 07:13 PM
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Location: Columbia, SC
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Shifter removal:

Remove wood panel (grip edge by cup holder, pull up)
Unplug range switch, there are 2 harnesses
The 2 wire harness is the backup lights, I believe this one has a retention clip
The multi wire harness is the computer harness, there is no retention clip on this one, it just pulls straight back, there is a grip on the plug head
Remove 4 x 5 mm hex bolts
Lift shifter out of floor pan, it will still be attached to the linkage
Clip comes off (same one they use on the old MBs)
Take shift knob off (grasp black collar under knob, rotate, pull knob off)
Look at body of shifter, there are 4 tabs around the perimeter that must be freed up to lift off the cover. I cut little strips out of a plastic food container to act as wedges to keep the tabs open after prying, or you will never get all 4 released at once.
Take the cover off, you will see the switch cartridge, the PRND4321 LEDs are in the top of the cartridge. Grasp the cartridge and pull up.

The cartridge comes apart pretty easy, just watch out for the spring in the W/S switch lever.

When you go to put it together you will see a little window in the side with an R next to it. The window has a white flag in it that is only present when the mechanism in the cartridge is aligned to the R position. You also need to have the shifter in the R position so that the pin on the main shaft goes into the slot in the mechanism on the bottom of the cartridge.
__________________
2014 ML350 Bluetec (wife's DD)
2008 E320 Bluetec (my DD)
2008 ML320 CDI (Older son's college DD)
1998 E300DT (Younger son's college DD)
1987 300TD sold to vstech
----------
gone but living on
1983 240D (body to greazzer, engine to t walgamuth)
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  #25  
Old 01-25-2017, 10:06 PM
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ROLLGUY
 
Join Date: Oct 2007
Posts: 5,909
Quote:
Originally Posted by jay_bob View Post
Shifter removal:

Remove wood panel (grip edge by cup holder, pull up)
Unplug range switch, there are 2 harnesses
The 2 wire harness is the backup lights, I believe this one has a retention clip
The multi wire harness is the computer harness, there is no retention clip on this one, it just pulls straight back, there is a grip on the plug head
Remove 4 x 5 mm hex bolts
Lift shifter out of floor pan, it will still be attached to the linkage
Clip comes off (same one they use on the old MBs)
Take shift knob off (grasp black collar under knob, rotate, pull knob off)
Look at body of shifter, there are 4 tabs around the perimeter that must be freed up to lift off the cover. I cut little strips out of a plastic food container to act as wedges to keep the tabs open after prying, or you will never get all 4 released at once.
Take the cover off, you will see the switch cartridge, the PRND4321 LEDs are in the top of the cartridge. Grasp the cartridge and pull up.

The cartridge comes apart pretty easy, just watch out for the spring in the W/S switch lever.

When you go to put it together you will see a little window in the side with an R next to it. The window has a white flag in it that is only present when the mechanism in the cartridge is aligned to the R position. You also need to have the shifter in the R position so that the pin on the main shaft goes into the slot in the mechanism on the bottom of the cartridge.
Awesome! Thanks!
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  #26  
Old 01-29-2017, 10:18 PM
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ROLLGUY
 
Join Date: Oct 2007
Posts: 5,909
Quote:
Originally Posted by ROLLGUY View Post
Well, the problem is still there, and I have not been paid for the work yet. Dave has just been warming the car up for a while before going to work, or parking it in the garage when available. I got a suggestion from Marc at Sun Valley Mercedes transmissions today, and it sounds promising. Marc had the same problem once, and tried everything to fix it. He told me how he diagnosed the problem. What he did, was to leave the car in the cold, and then use a hair drier to heat the area around the shifter. He found that the switch was sticking, thereby giving the trans computer a wrong signal. Once the cab was heated (or the area around the shifter heated to test his theory), the car shifted like it should. He replaced the entire shifter assembly (evidently the switch is hard to replace, or not available), and that fixed the problem. Fortunately Dave has an identical parts car. I will replace the shifter if that turns out to be the problem. I feel bad for having replaced the conductor plate (about $500 parts and labor), and that not being the problem. I probably should have called Marc first, rather than throw parts at it.........Rich

EDIT: Reading back, this was suggested but I must have missed it. I guess not having the proper (expensive) test equipment threw me off. A hair drier is not that expensive......Rich
The other morning my friend Dave parked his car outside and left an electric heater going inside the cab, and drove to work in the morning with no transmission issues. I guess I need to change the range selector switch. Is that the correct part name? I may just try to get a new one, rather than use the one in the parts car.
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