I made the mistake of letting a family member who "could definately do it -" fix a transmission oil leak on my '99 ml430. It was running beautiful prior but had a significant leak that required frequent top-offs.

I bought a transmission oil level checking tool to maintain the proper amounts until the repair was started and again, everything was fine to that point.

I bought a new gasket and filter kit for the AT oil pan. He drained and flushed the AT oil, removed the old pan, replaced the pan, filter and gasket. All good. Up until when he over-torked and stripped the AT oil pan bolts and a couple of the holes. I rethreaded the holes and bought new bolts. Again, all good. Until -

It started off strong and was shifting through all gears fine. After about 200 miles it started a slight grinding at low speed and especially around corners. The grind quickly progressed from nuissance to "oh no!". It got loud and was accompanied by a strong ratcheting vibration from start through 3rd gear and again, especially on cornering. It went into limp mode at that point.

Due to the location of the racheting and vibration (pretty much dead center under the shifter) and the fact that it was worse with higher power transfer demands, I jumped to a bad transfer case conclusion.

Up on stands it went - grabbed a new oil catch pan (to try and save as much of that overpriced hard to find tranny oil as possible) - opened the drain plug and waited for the beautiful red flow, that never came!

Yeah, "Mr. Of Course I Can Fix That" took 2 weeks on a 1 hr job then forgot to put transmission oil back in the transfer case; it had been running dry for almost 300 miles.

The transmission itself was filled with the right kind and amount of oil and since it had been shifting fine I decided my bad transfer case conclusion was correct.

I ordered a used ("but in excellent condition") transfer case and low range motor - disconnected the drive shafts - dropped the old TC - mounted the "new" one - reassembled the drivetrain and filled the TC with new oil.

This all took a couple months to get and replace the TC. During these months, the battery died. It took about an hour to jump it but finally fired it up. It sounded great. No smoke. No rattling. No extra parts flying from the undercarriage. Also . . . No transmission.

The shifter moves fine. There is a VERY slight feeling like it is going in to gear (but may just be the vibration from the shifter) but there is no power to any gear. It revs and idles like it is in Neutral no matter where the shifter is and never feels like there is any connection from the gears to the drive shafts.

A "car guy" suggested that since the battery was dead it may just be that the secondary battery is dead too and that will prevent the transmission from engaging.

Is that a possibility?

My suspicion is that since it hit Limp mode just prior to the new TC, the computer has locked the transmission in neutral as a safety measure?

The battery no longer takes a jump (yeah, it was that dead) and before I replace it for $180 plus the secondary battery for another $100 I'm wondering if anyone has had this issue or if a consensus can push me one way or the other.

Replace both batteries or replace primary battery then scan and reset any transmission codes that may appear. So, I'm also looking for an OBD tool that can scan and rest MB powertrain codes - saw a few listed in a forum prior to all this but can't find them anymore . . .

Any help will be awesome!

Thanks in advance . . .

 

Ouch! Well, really sad story, and a lesson learned.
But more importantly, the wrong the forum,
Mods please move to the 163 forum.
Sorry to hear of your problem.