Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 02-09-2021, 10:21 AM
Registered User
 
Join Date: Jul 2019
Location: Rust Belt
Posts: 435
TRRS Transmission Range Recognition Switch

Relatively "new to me" (10/2020) '97 E300D NA. 141K miles. Shifting issues with the 722.6. Purchased from original owner. Unfortunately, not much documented maint. history as they performed a lot of it (or, didn't) themselves.
As the cold weather began to take hold, noticed a delayed shift from 1st when the car wasn't up to operating temp. Checked the owners manual and it mentions the shift delay until the engine is warmed up. Ok, fine and good. Well, the situation got progressively worse.
Performed trans fluid/filter change (which was planned, anyway). Also plug adapter. The TCU had minor fluid ingress, just trace amounts (thank you lucky stars). Not positive, but it looked like the trans fluid had never been changed. Got everything back together, proper fluid level, etc. and no help for the delayed shifts.
However, when it would function properly, the trans felt MUCH better with the new fluid!
Started scouring the "forums" and saw mention of the indicator lights on the shift quadrant. The indicators for "D" and "4" were a little wonky and not always lit. Hadn't put 2 and 2 together at this point. Being new to this car, I assumed the lighted "PRND/4321" were simply to let you know what gear you were in while driving at night.....didn't know about the "TRRS".
So, to make a long story even longer.....if I play around with the shift lever, I can get the "D" to stay illuminated and the trans functions flawlessly. Same with "4". If, due to bumps/vibration, the shift lever moves slightly and the "D" light goes out, back to not shifting properly.
Looking for insight/advice before "biting the bullet" on this $100+ part. Seems like the cause of my issues, yes? Am I missing something? Is this control unit "plug and play"?
Is it relatively simple to install or will the gear selector unit explode, like an overwound clock, when I attempt to take it apart?
Sorry for the "novel", but realize background info is important when troubleshooting in cyberspace.
Thanks, in advance. This is a great forum and has been a lot of help to me on my "other" and first Benz, an '83 240D. I've had that car for about 3 years.


Last edited by 123boy; 02-09-2021 at 04:26 PM.
Reply With Quote
  #2  
Old 02-10-2021, 01:20 PM
jay_bob's Avatar
Control Freak
 
Join Date: Oct 2011
Location: Columbia, SC
Posts: 3,941
The gear shift switch/LED assembly on these is in a white cartridge inside the shifter.

They are vulnerable to spilled drinks, wet dogs, etc.

Pull the shifter out of the car (unplug harnesses at the rear, 4 screws into the body, lift up, undo the linkage clip)

Take to bench and separate the cover from the body.

The white cartridge pulls out but you have to put the lever in Reverse to get it to release.

Once you do that you can open the cartridge. There is one tiny spring for the W/S switch lever but other than that it's a circuit board and a slider contact assembly.

Clean it up with alcohol and put back together.

When you go to reinsert the cartridge you will see a window with an R next to it. Rotate the internal cam so the white dot shows up in the window, and then, you guessed it, the handle has to be in the R position before inserting it.

If that doesn't fix it the part has no 'version coding' so any replacement is plug and play.
__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech
Reply With Quote
  #3  
Old 02-12-2021, 12:15 AM
Registered User
 
Join Date: Jul 2019
Location: Rust Belt
Posts: 435
Thanks "jay_bob". Excellent response and just what I needed. Straight forward and to the point.
Appreciate it very much.

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 07:59 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page