Strange Tranny Behavior at Altitude
Thread Starter
MBWorld Fanatic!
Joined: Apr 2008
Posts: 1,399
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From: Bay Area, California
2015 E63s AMG, 2020 GLC 43 AMG
Strange Tranny Behavior at Altitude
Hey Guys,
We have a 2013 GLK350 and a few months ago on our only trip Tahoe in this vehicle, we were having very noticeable glitches with shifting. It started at about 4500 feet and remained a problem through the entire trip until we drove home and returned to the lower altitude.
When ever it needed to downshift, it felt like it would slip first and then slam into gear. Not real pleasant. But again, after we came back under 4000 feet or so, the problem disappeared. It hasn't come back in 4 months since.
My guess is that it must have something to do with fuel mixture changing at altitude which was causing the ECU or something to freak out. Or possibly a drop in ambient atmospheric pressure somehow effects the internal pressure of the tranny.
Anyway, it is going to the dealer tomorrow and we told them about this. But unless they see some clear trouble code on their OBD, we are gonna get the famous "could not replicate" Guess we will have to drive with their mechanic for 3 hours to Tahoe to prove it! lol
Anybody else have this happen to them or heard of it?
Thanks in advance
We have a 2013 GLK350 and a few months ago on our only trip Tahoe in this vehicle, we were having very noticeable glitches with shifting. It started at about 4500 feet and remained a problem through the entire trip until we drove home and returned to the lower altitude.
When ever it needed to downshift, it felt like it would slip first and then slam into gear. Not real pleasant. But again, after we came back under 4000 feet or so, the problem disappeared. It hasn't come back in 4 months since.
My guess is that it must have something to do with fuel mixture changing at altitude which was causing the ECU or something to freak out. Or possibly a drop in ambient atmospheric pressure somehow effects the internal pressure of the tranny.
Anyway, it is going to the dealer tomorrow and we told them about this. But unless they see some clear trouble code on their OBD, we are gonna get the famous "could not replicate" Guess we will have to drive with their mechanic for 3 hours to Tahoe to prove it! lol
Anybody else have this happen to them or heard of it?
Thanks in advance
Thread Starter
MBWorld Fanatic!
Joined: Apr 2008
Posts: 1,399
Likes: 202
From: Bay Area, California
2015 E63s AMG, 2020 GLC 43 AMG
Final Update
Turns out the tranny was a quart low on fluid. From experience I can confirm that low tranny fluid will cause shifting issues. These issues will be exaggerated in altitude.
I guess we will see next winter on our next trip to Tahoe.
Real question that still remains is:
How the h*ll is the tranny down a quart on 2 year old vehicle? There are no visible leaks. Hmmmmmmm????
I guess we will see next winter on our next trip to Tahoe.
Real question that still remains is:
How the h*ll is the tranny down a quart on 2 year old vehicle? There are no visible leaks. Hmmmmmmm????
MBWorld Fanatic!
Joined: Jan 2009
Posts: 2,780
Likes: 115
From: Northern NJ
GLK 350 / Porsche 993
Yea a quart is a lot to leak out. Although transfer cases often leak on 4matics, there is even a TSB on this. But on 2 year old car...?
Hope they measured the level correctly. It's not that simple
Hope they measured the level correctly. It's not that simple
Thread Starter
MBWorld Fanatic!
Joined: Apr 2008
Posts: 1,399
Likes: 202
From: Bay Area, California
2015 E63s AMG, 2020 GLC 43 AMG
As I reported in the w212 thread ( E63) they just put entirely new Xenon assemblies in my AMG that is 1 month away from out of factory warranty. And I dont think the extended warranty covers this.
Interesting thing is, I didnt even bring it to their attention. My SA noticed some burn in issue on the lenses.
This combined with the new brakes on the 2013 GLK for $120 has me quite appreciative of MB.
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Joined: Mar 2013
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Yikes:
Turns out the tranny was a quart low on fluid. From experience I can confirm that low tranny fluid will cause shifting issues. These issues will be exaggerated in altitude.
I guess we will see next winter on our next trip to Tahoe.
Real question that still remains is:
How the h*ll is the tranny down a quart on 2 year old vehicle? There are no visible leaks. Hmmmmmmm????
I guess we will see next winter on our next trip to Tahoe.
Real question that still remains is:
How the h*ll is the tranny down a quart on 2 year old vehicle? There are no visible leaks. Hmmmmmmm????
MBWorld Fanatic!
Joined: Jan 2009
Posts: 2,780
Likes: 115
From: Northern NJ
GLK 350 / Porsche 993
What happened to your xenons? You don't have best luck with MBs, good thing dealer is taking care of you.
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Thread Starter
MBWorld Fanatic!
Joined: Apr 2008
Posts: 1,399
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From: Bay Area, California
2015 E63s AMG, 2020 GLC 43 AMG
Apparently it is a common issue, V-burn in, a lot of guys, according to the thread I posted on the AMG board fought tooth and nail with MB to replace theirs over this issue.
I have been buying new Benzes since mid 90's and have a great relationship with my SA. He took care of me, plain and simple.
And as a reference, I had my 2000 E55 for almost 16 years without ever having any real "bad luck" as you say.
Best car I ever owned. Just hoping the new E63 holds up as well!!
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Joined: Jun 2012
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From: Oxnard, California
2018 GLC 300 4Matic, '69 Nova 350
Just drove last week from SoCal to Reno and back in my 2012 GLK. Transmission shift was smooth and very pleasant when passing RX 350s, BMW X5s and other SUVs uphill to 8400 Ft. Only issue was brake pedal travel further than before and steering wheel rattling vibration when braking which I figured would be from hot brakes probably warping rotors. Not the case, took it to dealer yesterday and have bad brake booster. Getting replaced this week. Will have to fight with dealer if rotors are warped...
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Joined: Jun 2014
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2014 GLK250, 1983 Caterham super 7
Your trans may have left the factory with a "less than full" fluid level. We had to deal with that all the time on our two BMW's which didn't have dip sticks. The engines take 6.5 liters. Most shops and dealers & me as well normally only put in 6 so you didn't have an open bottle hanging around. So we just waited till the car told us that it was one liter down, then topped it up.
So it may have been low to start with, And likely hasn't used as much as it indicated. Best advice would be to check the trans oil when you check your engine oil level prior to a trip. You do check your oil now and then don't you?
So it may have been low to start with, And likely hasn't used as much as it indicated. Best advice would be to check the trans oil when you check your engine oil level prior to a trip. You do check your oil now and then don't you?
