08 CLK 550 Transmission issues
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 16
Likes: 0
2008 550 clk with AMG package
08 CLK 550 Transmission issues
Hi everyone. We bought used from car max. It had 47,000 miles on it. Was a M.B. lease car and was maintained by them but they never did the trans service. We had car max get them to do it. Now at 50,800 miles showing this started.
The car will slam into 2nd. gear when in stop and go traffic. If you go wide open throttle from a standstill or rolling 10 or 20 mph it will defuel then run hard from 1st and then slam into 2nd gear and then pulls the power off quite a bit until it shifts to 3rd. Then it goes thru the rest normally.
We don't run it hard we are in our sixties. I was told at the time of service that the de fuel when kicking sown was normal. I used to spin wrenches for a living but only did brakes and such on M.B. products, but I'm guessing it is a bad shift solenoid or judging by the reduced power/limp in 2nd. gear that maybe the clutch packs are going south. Any idea's ? Thanks
The car will slam into 2nd. gear when in stop and go traffic. If you go wide open throttle from a standstill or rolling 10 or 20 mph it will defuel then run hard from 1st and then slam into 2nd gear and then pulls the power off quite a bit until it shifts to 3rd. Then it goes thru the rest normally.
We don't run it hard we are in our sixties. I was told at the time of service that the de fuel when kicking sown was normal. I used to spin wrenches for a living but only did brakes and such on M.B. products, but I'm guessing it is a bad shift solenoid or judging by the reduced power/limp in 2nd. gear that maybe the clutch packs are going south. Any idea's ? Thanks
MBWorld Fanatic!
Joined: Jun 2008
Posts: 1,227
Likes: 61
From: Atlanta Metro
2008 clk550 - Navigator - Frontier
My 08 550 has about 48k miles and the change from 1st to 2nd is pretty hard. I generally determine the shifts myself. Almost never use the D and go method.
I also almost never use the "C" mode. Though the car would start off in 2nd; have you used the "C" mode and if so, are the rest of the shifts ok?
BTW, I am in my 60's and I am determined to never be the one impeding traffic.
I also almost never use the "C" mode. Though the car would start off in 2nd; have you used the "C" mode and if so, are the rest of the shifts ok?
BTW, I am in my 60's and I am determined to never be the one impeding traffic.
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 16
Likes: 0
2008 550 clk with AMG package
Hi Fatz, it slams really hard and seems and doesn't act right before it slams. It didn't do it before. It also pulls about 50% of the power off thru 2nd and then shifts to 3rd OK back to 100 % power and runs the way it should thru the rest of the gears. It was 10,000 miles past the recomended milage for it's trans service before they did it.
Last edited by cowboywildbill; Sep 18, 2012 at 05:09 PM.
MBworld Guru
Joined: Dec 2009
Posts: 10,782
Likes: 1,011
NO LONGER ACTIVE
Two things: First, do a transmission fluid and filter change! It should have been done at 39K. Many harsh shifting problems are cause by low fluid or sludgy fluid. Doing the service will fix that. Second, get your authorized MBZ dealer (the only ones who can do this) "flash" the TCU with the latest code. My transmission was doing this and the latest TCU code made a huge difference. It not only solves the 1-2 hard shift or slippage problems, it makes all the shifts much smoother. In gentle driving, it almost feels like a CVT with no perceptible shifting sensations at all.
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 16
Likes: 0
2008 550 clk with AMG package
The M.B. dealership did the trans service when we bought the car about 4,000 miles ago. They said the fluid was dirty and dark but nothing bad was found in the pan.
They have the car now and we are waiting to hear what they find. I'm hoping if it has anything serious that they will replace the trans and torque converter rather than throw parts at it. I was told that the dealers don't usually rebuild the units but just replace them.
They have the car now and we are waiting to hear what they find. I'm hoping if it has anything serious that they will replace the trans and torque converter rather than throw parts at it. I was told that the dealers don't usually rebuild the units but just replace them.
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 16
Likes: 0
2008 550 clk with AMG package
OK here is the update, They said the car is ready and we will pick it up tomorrow. The dealer said that no codes were present and that they can't repair it unless codes are present even though it doesn't shift correctly.
The dealer said the best they can do is a software update and then it will take a few hundred miles to relearn our driving habbits and that still may not take care of the issue. Sounds screwy to me that it shifts fine for 47,000 or rather 49,000 miles and then shifts harshly. I had a typo on the milage in my origional post. We have put about 4,000 on the car before it started having the trans issues. We will find out tomorrow if it helped.
The dealer said the best they can do is a software update and then it will take a few hundred miles to relearn our driving habbits and that still may not take care of the issue. Sounds screwy to me that it shifts fine for 47,000 or rather 49,000 miles and then shifts harshly. I had a typo on the milage in my origional post. We have put about 4,000 on the car before it started having the trans issues. We will find out tomorrow if it helped.
Last edited by cowboywildbill; Sep 21, 2012 at 03:51 PM.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 16
Likes: 0
2008 550 clk with AMG package
Car Max took our CLK to a local Dulles,Va. Mercedes dealer for the repairs.They claimed that they did do the update.
The transmission still bangs into 2nd gear and slips even when driving very gently. They claim it's normal for it to do that.????? It didn't do it before???
They were also supposed to repair the Sirius/XM radio that keeps dropping the 50's station. They said it's not the receiver but that the 50's station always does that.
We have three other vehicles that don't have that issue with that channel, or any stations for that matter.
I think we wasted our money buying the car max extended warranty!
The transmission still bangs into 2nd gear and slips even when driving very gently. They claim it's normal for it to do that.????? It didn't do it before???
They were also supposed to repair the Sirius/XM radio that keeps dropping the 50's station. They said it's not the receiver but that the 50's station always does that.
We have three other vehicles that don't have that issue with that channel, or any stations for that matter.
I think we wasted our money buying the car max extended warranty!
Last edited by cowboywildbill; Sep 23, 2012 at 08:10 AM.
MBWorld Fanatic!
Joined: Jun 2008
Posts: 1,227
Likes: 61
From: Atlanta Metro
2008 clk550 - Navigator - Frontier
Cowboywildbill,
Sorry ur having so much trouble witht he tranny. We have the same car. Bought mine new. It is a great car, but I can understand your frustration.
The people on this forum have witnessed, experienced, or discussed just about all that has ever gone wrong witht his car. You can see from my number of ports that I am not one of them.
I would put the car in a "sink or swim" situation.. Since the dealers have checked it and it is supposed to be mechanically ok, I would reset the ECU and give it a thorough workout (SAFELY). I would turn off the traction control and manually row through the gears in the "S" mode......... drive it hard for 30-50 miles. Then I would put it in the "C" mode and drive it like grandma for 10 miles.
The car makes a tremendous amount of torque. I would either break it so it could be repaired or be left thinking "Wow".
Since the techs are saying it is ok/normal, I would find another one on sale at a dealer and test drive it.......
Ihave sometimes lost a station when on the highway. I always thought it was due to a weak signal as the terrain changed (trees and hills). I have never experienced a lost around the/a city, unless the car was in the garage....
Sorry ur having so much trouble witht he tranny. We have the same car. Bought mine new. It is a great car, but I can understand your frustration.
The people on this forum have witnessed, experienced, or discussed just about all that has ever gone wrong witht his car. You can see from my number of ports that I am not one of them.
I would put the car in a "sink or swim" situation..
Since the dealers have checked it and it is supposed to be mechanically ok, I would reset the ECU and give it a thorough workout (SAFELY). I would turn off the traction control and manually row through the gears in the "S" mode......... drive it hard for 30-50 miles. Then I would put it in the "C" mode and drive it like grandma for 10 miles.The car makes a tremendous amount of torque. I would either break it so it could be repaired or be left thinking "Wow".
Since the techs are saying it is ok/normal, I would find another one on sale at a dealer and test drive it.......
Ihave sometimes lost a station when on the highway. I always thought it was due to a weak signal as the terrain changed (trees and hills). I have never experienced a lost around the/a city, unless the car was in the garage....
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 16
Likes: 0
2008 550 clk with AMG package
Thanks Fatz, I will do that. The radio issue is just the one Sirius station and doesn't do it on the other stations. Something in the receiver. They just don't want to eat the repair bill. And I pointed out the radio issue on the first day we got the car and they said yes there is something wrong with it and it would be fixed. They checked it out a month after that. They have a Mercedes Master Tech at the Car Max shop. He said it wasn't in the antennae and that a dealer would have to test and probably replace the XM receiver. OH Well. They have had our car a total of 3 weeks "3 visits" for these and one other issue. We love the car I will hold their feet to the fire until they resolve these issues.
MBworld Guru
Joined: Dec 2009
Posts: 10,782
Likes: 1,011
NO LONGER ACTIVE
There have been many complaints over the odd shifting behavior of the 722.9 transmission, but it's mostly related it it "hunting" for gears or downshifting into a lower gear than expected. Slipping and banging into gear when shifting from 1-2 is NOT normal!
After mine was at the dealer for the timing gear repair, it started doing this. I suspected it was because they disconnected a transmission fluid cooling line, lost some fluid, and didn't re-check the level. When I took it back, they did say it was "a little" low, and did the TCU reflash. I suspect it was the fluid level correction that solved the problem and not necessarily the reflash. It had been running he same TCU code for 30K miles, so why start acting weird all of the sudden? And the only thing that changed was pulling the engine for the gear repair, which I know meant disconnecting some transmission lines. I would almost bet that yours is low on fluid, and it doesn't take much to make a difference.
Anyhow, after I did my own transmission fluid change, I can see how difficult and time consuming it is to get the level correct. First, you fill it by pumping fluid into through the drain plug. You have to pump more fluid in that needed, then warm it up to specific temperature (45C/113F). With the engine still running, you open the drain plug and let the excess stream out until it slows to a trickle. The problem is, this isn't operating temperature, but just a brief point on the way up, so you have to be quick.
After mine was at the dealer for the timing gear repair, it started doing this. I suspected it was because they disconnected a transmission fluid cooling line, lost some fluid, and didn't re-check the level. When I took it back, they did say it was "a little" low, and did the TCU reflash. I suspect it was the fluid level correction that solved the problem and not necessarily the reflash. It had been running he same TCU code for 30K miles, so why start acting weird all of the sudden? And the only thing that changed was pulling the engine for the gear repair, which I know meant disconnecting some transmission lines. I would almost bet that yours is low on fluid, and it doesn't take much to make a difference.
Anyhow, after I did my own transmission fluid change, I can see how difficult and time consuming it is to get the level correct. First, you fill it by pumping fluid into through the drain plug. You have to pump more fluid in that needed, then warm it up to specific temperature (45C/113F). With the engine still running, you open the drain plug and let the excess stream out until it slows to a trickle. The problem is, this isn't operating temperature, but just a brief point on the way up, so you have to be quick.
