So I have been having these sort of hard shift that happens when I go from 4th to 5th gear. When it starts to shift there is a big jolt and the RPMs will jump up 200 RPMs for a second and then it will shift. It doesn't happen all the time but when it does you can definitely feel it.
trkraimer
- Status
It happens when it's cold and warm. Sometimes it will be super smooth and then sometimes it throws you back.
How would I check if it was done and how do I do it? All of the fluids were changed last summer when I bought the car, the dealership said it was all done.
you have to confirm it was done with them...unless you take their word
you can take a sample and see what condition the trans fluid is in
www.slkworld.com
you can take a sample and see what condition the trans fluid is in
7G tranny fluid change DIY
Ok I finally got round to changing out the tranny lube and filter on the 7G box in my 55 which as many will know requires a pump to get the lube in as there is only a drain point and no fill point. Well its done and definitely a PITA so unless your into DIY stop reading now. I made the pump...
www.slkworld.com
How do you know if your transmission fluid is bad?
Good transmission fluid is clear or pink-tinted. If it's a deep red or brown color, then it is old and dirty. You need to replace the transmission fluid to avoid any damage to your transmission. Look to see if there are any visible particles as well, as this can also mean you need to change the fluid.
Good transmission fluid is clear or pink-tinted. If it's a deep red or brown color, then it is old and dirty. You need to replace the transmission fluid to avoid any damage to your transmission. Look to see if there are any visible particles as well, as this can also mean you need to change the fluid.
Transmission Fluid Needs Changing | My Transmission Experts
Learn more from My Transmission Experts. Your local mechanics in Houston, Katy, Kingwood, and Montgomery TX.
www.mytransmissionexperts.com
Here’s what you should be watching for.
- Dirty transmission fluid
- Transmission whining noise
- Gears slipping
- Can’t go into reverse gear
- Slipping out of gear
- Engine running hot
- Grinding noise
I'd want it on SDS to see what's going on, could be lots of issues, anything else is just guesswork 
When did it last have FULL Oil and Filter change (10 litres) and is it certain that the level is correct ?
When did it last have FULL Oil and Filter change (10 litres) and is it certain that the level is correct ?
I think you are being obtuse. Change the filter, the fluids and if necessary the connector to the ECU which can leak, oil can get into the harness and cause shorts etc. Last time my Indy did mine it was $325 CDN all in. You have to remember there are what 8 solenoids on the conductor plate, there are three speed sensors, the valve body itself as well as the clutch paks. The TCU is bolted to the conductor plate as well (and is car specific. You just cannot swap out old for new or used).
These are complex devices and if a full service is not the answer then a pro would be where I would go to solve the OP's issues.
These are complex devices and if a full service is not the answer then a pro would be where I would go to solve the OP's issues.
It's not in there, nor is it in their 722.9 manual nor in WIS. But yes, I am doing one right now. I just thought you might have run into it but I didn't expect an answer. It seems I'm always finding areas of this car that no-one knows about
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Not only that, but you seem to be slightly aphasic as well....Dave2302 said:🤣 🤣 🤣 Your sense of humour is like mine
The honest answer is NO (not off the top of my head), it's been 20 years since I rebuilt 7Gs and I'm fast approaching 61 years young so my long term memory is pants these days.
I'm 53 and I pulled that tranny out with a floor jack while on a creeper
I was a lot fitter when in my early 50's Mind I'm still climbing and balancing on ladders etc to do maintenance on our buildings even these dayz
I wouldn't touch it without a 2 Poster and Trans Jack, to much arthritis from all the activities I pursued and bones I busted when younger and I still do some of that stuff today
Mind I'm still climbing and balancing on ladders etc to do maintenance on our buildings even these dayz I wouldn't touch it without a 2 Poster and Trans Jack, to much arthritis from all the activities I pursued and bones I busted when younger and I still do some of that stuff today
Well, another day, another interesting issue with the trans rebuild. Turns out, it's not just the B1 clutch freeplay specs that are not available for an 8 disk stack, it's also the K1 specs. The K1 has also has 8 frictions and the specs only go to 6.....
So...I'm ready to draw some conclusions from this effort to blueprint the 722.906....
First, since the one adjustment snap ring I ordered from MB (so far) had to come from Germany - clearly no-one is adjusting the gap on the clutch stacks during a rebuild because...it would be a common stocked item (ie local).
Second, Mercedes does show 8 frictions for both the B1 and K1 in WIS. We can infer from that that MB is fully aware this is how they built them.
Third, Mercedes specs for the gap stop at 5 frictions for the B1 and 6 frictions for the K1. As such, they forgot to document the spec for the 8 clutch stack, probably due to a production change that they forgot to incorporate into WIS....
Fourth, and in my opinion, most damning, is that no-one in the transmission rebuilding industry, including ATRA, has run into this. We can infer some really important things from that. One of which is that obviously, none of the rebuilders are checking/measuring the clutch gap. Instead, what they are likely doing is slamming a set of clutches in it and sending it out the door! Good enough, right?
Not taking into account, of course, that the clutches they are using are not going to be identical thickness, whether you buy them from Mercedes or whomever. There are manufacturing tolerances that tend to, if you'll forgive the expression, stack up.....
Where this gets to be vital, is when you are doing a 'diagnosis by exclusion' ie, you have a 3-2 coast down clunk and Xentry logs from the TCU indicate that it can no longer adjust B1....and you want to ensure the clutch stack gap is properly adjusted...ie, to exclude that from causing the issue......
So...I'm ready to draw some conclusions from this effort to blueprint the 722.906....
First, since the one adjustment snap ring I ordered from MB (so far) had to come from Germany - clearly no-one is adjusting the gap on the clutch stacks during a rebuild because...it would be a common stocked item (ie local).
Second, Mercedes does show 8 frictions for both the B1 and K1 in WIS. We can infer from that that MB is fully aware this is how they built them.
Third, Mercedes specs for the gap stop at 5 frictions for the B1 and 6 frictions for the K1. As such, they forgot to document the spec for the 8 clutch stack, probably due to a production change that they forgot to incorporate into WIS....
Fourth, and in my opinion, most damning, is that no-one in the transmission rebuilding industry, including ATRA, has run into this. We can infer some really important things from that. One of which is that obviously, none of the rebuilders are checking/measuring the clutch gap. Instead, what they are likely doing is slamming a set of clutches in it and sending it out the door! Good enough, right?
Not taking into account, of course, that the clutches they are using are not going to be identical thickness, whether you buy them from Mercedes or whomever. There are manufacturing tolerances that tend to, if you'll forgive the expression, stack up.....
Where this gets to be vital, is when you are doing a 'diagnosis by exclusion' ie, you have a 3-2 coast down clunk and Xentry logs from the TCU indicate that it can no longer adjust B1....and you want to ensure the clutch stack gap is properly adjusted...ie, to exclude that from causing the issue......
I agree with all of your conclusions
We did used to adjust Clutch Gaps on everything that required it, but remember it was 15 years ago when I sold my share of the Trans Firm to my Business Partner, (7G was very new on the block back then) so perhaps the 8 Clutch set didn't come out until later years when MB started fitting 'em on the back of higher torque motors !!
I did check my archived 7G files last evening, and sadly all the 7G's we rebuilt back then were, (as you have found out) max 6 clutch, therefore I don't have the figure you need
However, what I would do in your situation is to set it a small amount larger perhaps * ...................
My theory being the clunk is caused by a slight bind up.
Since the 5 speed auto uses Sprags (OWC's) and clunks like a mother if a Sprag is bad .................
The 7G doesn't have any Sprags therefore IMHO you need B1 to bite a little later to avoid the clunk, or K1 to release a tad earlier.
* Is that Brake 1 adaptive right into full scale negative, it's a bit of an uneducated guess since I've never had that issue, but my guess would be if it's Gap related they would be negative if trying to slow down B1 application ?????
A long shot and you may well have checked out the EHVB already ....
Y3 / 8y2 Solenoid Screen would be worth a look in case it is claggy and slowing the release of K1 causing a bind up.
Worth a look at Y3 / 8y5 Solenoid Screen too just in case
Shame you're not in UK, I'd love to take you and your Valve Block down to my old firm and run it on the Hydra-test, best bit of (expensive, very expensive) Kit we ever bought.
HTH
We did used to adjust Clutch Gaps on everything that required it, but remember it was 15 years ago when I sold my share of the Trans Firm to my Business Partner, (7G was very new on the block back then) so perhaps the 8 Clutch set didn't come out until later years when MB started fitting 'em on the back of higher torque motors !!
I did check my archived 7G files last evening, and sadly all the 7G's we rebuilt back then were, (as you have found out) max 6 clutch, therefore I don't have the figure you need
However, what I would do in your situation is to set it a small amount larger perhaps * ...................
My theory being the clunk is caused by a slight bind up.
Since the 5 speed auto uses Sprags (OWC's) and clunks like a mother if a Sprag is bad .................
The 7G doesn't have any Sprags therefore IMHO you need B1 to bite a little later to avoid the clunk, or K1 to release a tad earlier.
* Is that Brake 1 adaptive right into full scale negative, it's a bit of an uneducated guess since I've never had that issue, but my guess would be if it's Gap related they would be negative if trying to slow down B1 application ?????
A long shot and you may well have checked out the EHVB already ....
Y3 / 8y2 Solenoid Screen would be worth a look in case it is claggy and slowing the release of K1 causing a bind up.
Worth a look at Y3 / 8y5 Solenoid Screen too just in case
Shame you're not in UK, I'd love to take you and your Valve Block down to my old firm and run it on the Hydra-test, best bit of (expensive, very expensive) Kit we ever bought.
HTH
Thank you Dave for your reply! My apologies to everyone for my anger post. I actually bought beer last night, had 3, and paced back at forth raging at the machine Last part of my rant, I am not actually a transmission rebuilder. The first, and last one I did, was in the late 80's, a Turbo 350.
The trans is not just being rebuild for the 3-2 coast down clunk but that is a big part of it, and, as mentioned, in that respect it's diagnosis by exclusion. I previously cleaned the valve body (total strip down, spotless, and also cleaned every solenoid spotless using the ultrasonic cleaner). I did not replace the solenoid o-rings at that time.
During this rebuild, the VB was again stripped, the solenoid O-rings were replaced, every solenoid is again spotless, and I Ohm-checked each one as well as replaced every checkball and check valve as well as the two rubber ones. Each control valve was pulled, the springs and bores were checked. Using the same diagnosis by exclusion, the only thing that should be left as a possible cause on the VB side is a worn control valve bore OR wrong software in the TCU. Even though I have a vacuum pump I cannot see any practical way of testing the valve bores.
In any event, the VB is on the outside of the trans so it can be revisited later if required. Not ideal, but my thinking is we need to know for a fact that the internal side of the trans is perfect just in case the 3-2 is still there.
For the last part of my rant, and to get it all out of my system, I viewed my job as this. I would have to do meticulous work and be prepared to spent extra $$ in case I found issues with hard parts, which I did. About $1,500 worth. In effect, I viewed my role as one of blueprinting the transmission. That's my job. If I screw it up it's on me and I'm fine with that. Other than replacing worn items, I see the crux of the job being cleanliness and measuring the clutch stacks and the end play at the rear of the trans. Get that all right and I would be able to drive down the road knowing that internally the trans is perfect. Should the 3-2 still be there, I would likely focus on software next.
Attached is the log of the TCU showing before rebuild adaptation times. I'm no expert on this but the B1 seems to consistently show up as -20 My take on that is that means the TCU cannot adapt it anymore. It could not be manually adapted using DAS. Could be solenoid O-ring, could be clutch wear, but I am certain that has all been addressed, which leaves setting the clutch stack height/gap. For obvious reasons, to me, that is essential.
From my layman's perspective, that should mean that everything from the valve body to the solenoid to the clutch stack is 100% on spec. Thus, if the 3-2 is still there, look to software. That should be the only place the issue could be hiding.
I may well be worried about nothing, but I'm here now. What never occurred to me was that once again I could be let down by third party's (Mercedes or the book I am using). Like I said, the onus is on me to do good work, conversely, the onus is on them to provide me with the actual spec to do that good work.
To your point, it's interesting that we are talking about B1 and K1. Because I'm a laymen I don't really understand how the trans works, but just from this statement from you;
"The 7G doesn't have any Sprags therefore IMHO you need B1 to bite a little later to avoid the clunk, or K1 to release a tad earlier." I can infer that I am indeed in the right area, and that I am indeed right to be concerned with these gaps.
My theory during the rebuild has been this, set the gaps to the minimum side of the spec to give the TCU the most adjustability range over time. This goes towards longevity. Ie, if the gaps are all on the tight side the TCU should be able to adapt them much easier for the longest period of time as the clutches wear. You've now raised a very good point which seems to me to be if the gap is larger than the braking may be gentler, if I understand you correctly.
On the other hand, isn't the TCU supposed to adjust the rate and the pressure and the time to give me that perfect apply? And of course, that comes back to software.....
I may well be worried about nothing. It's entirely possible it goes back together and presto, it's perfect (after clearing and manually adapting with DAS). But all of the fog could be taken out of this mess if the idiots at Mercedes, that specifically tell you the trans must have 8 B1 and 8K1 clutches, had actually also given the specs for those stacks....
When you explain to me what's happening during 3-2 coast down with respect to B1 and K1 it's as if a light is going off and that is encouraging. It means all the rouble I am having is being focussed in the right area. Bear in mind, when I look at the log (attached) all I know is the MB seems to indicate anything from -15 to -20 is on the bad side with -20 being out of range.
Lastly (I promise!) It's beyond me that a trans from 2006, that I think 8 million of them were made, has a documentation issue! You would think that people twigged on to this long ago and that MB, or the industry, had a bulletin on revised charts for clutch gap and that the MB service manual would have been updated. How the hell can someone, in 2022, be 'discovering' this for the very first time? And for that matter, what the hell have the rebuilders been doing all these years?
If you'll bear with me, I'll send you a quick PM about some more confidential stuff on this issue. But many thanks for your reply, it has confirmed for me that I am in the right area and that is huge.
Last part of my rant, I am not actually a transmission rebuilder. The first, and last one I did, was in the late 80's, a Turbo 350.The trans is not just being rebuild for the 3-2 coast down clunk but that is a big part of it, and, as mentioned, in that respect it's diagnosis by exclusion. I previously cleaned the valve body (total strip down, spotless, and also cleaned every solenoid spotless using the ultrasonic cleaner). I did not replace the solenoid o-rings at that time.
During this rebuild, the VB was again stripped, the solenoid O-rings were replaced, every solenoid is again spotless, and I Ohm-checked each one as well as replaced every checkball and check valve as well as the two rubber ones. Each control valve was pulled, the springs and bores were checked. Using the same diagnosis by exclusion, the only thing that should be left as a possible cause on the VB side is a worn control valve bore OR wrong software in the TCU. Even though I have a vacuum pump I cannot see any practical way of testing the valve bores.
In any event, the VB is on the outside of the trans so it can be revisited later if required. Not ideal, but my thinking is we need to know for a fact that the internal side of the trans is perfect just in case the 3-2 is still there.
For the last part of my rant, and to get it all out of my system, I viewed my job as this. I would have to do meticulous work and be prepared to spent extra $$ in case I found issues with hard parts, which I did. About $1,500 worth. In effect, I viewed my role as one of blueprinting the transmission. That's my job. If I screw it up it's on me and I'm fine with that. Other than replacing worn items, I see the crux of the job being cleanliness and measuring the clutch stacks and the end play at the rear of the trans. Get that all right and I would be able to drive down the road knowing that internally the trans is perfect. Should the 3-2 still be there, I would likely focus on software next.
Attached is the log of the TCU showing before rebuild adaptation times. I'm no expert on this but the B1 seems to consistently show up as -20 My take on that is that means the TCU cannot adapt it anymore. It could not be manually adapted using DAS. Could be solenoid O-ring, could be clutch wear, but I am certain that has all been addressed, which leaves setting the clutch stack height/gap. For obvious reasons, to me, that is essential.
From my layman's perspective, that should mean that everything from the valve body to the solenoid to the clutch stack is 100% on spec. Thus, if the 3-2 is still there, look to software. That should be the only place the issue could be hiding.
I may well be worried about nothing, but I'm here now. What never occurred to me was that once again I could be let down by third party's (Mercedes or the book I am using). Like I said, the onus is on me to do good work, conversely, the onus is on them to provide me with the actual spec to do that good work.
To your point, it's interesting that we are talking about B1 and K1. Because I'm a laymen I don't really understand how the trans works, but just from this statement from you;
"The 7G doesn't have any Sprags therefore IMHO you need B1 to bite a little later to avoid the clunk, or K1 to release a tad earlier." I can infer that I am indeed in the right area, and that I am indeed right to be concerned with these gaps.
My theory during the rebuild has been this, set the gaps to the minimum side of the spec to give the TCU the most adjustability range over time. This goes towards longevity. Ie, if the gaps are all on the tight side the TCU should be able to adapt them much easier for the longest period of time as the clutches wear. You've now raised a very good point which seems to me to be if the gap is larger than the braking may be gentler, if I understand you correctly.
On the other hand, isn't the TCU supposed to adjust the rate and the pressure and the time to give me that perfect apply? And of course, that comes back to software.....
I may well be worried about nothing. It's entirely possible it goes back together and presto, it's perfect (after clearing and manually adapting with DAS). But all of the fog could be taken out of this mess if the idiots at Mercedes, that specifically tell you the trans must have 8 B1 and 8K1 clutches, had actually also given the specs for those stacks....
When you explain to me what's happening during 3-2 coast down with respect to B1 and K1 it's as if a light is going off and that is encouraging. It means all the rouble I am having is being focussed in the right area. Bear in mind, when I look at the log (attached) all I know is the MB seems to indicate anything from -15 to -20 is on the bad side with -20 being out of range.
Lastly (I promise!) It's beyond me that a trans from 2006, that I think 8 million of them were made, has a documentation issue! You would think that people twigged on to this long ago and that MB, or the industry, had a bulletin on revised charts for clutch gap and that the MB service manual would have been updated. How the hell can someone, in 2022, be 'discovering' this for the very first time? And for that matter, what the hell have the rebuilders been doing all these years?
If you'll bear with me, I'll send you a quick PM about some more confidential stuff on this issue. But many thanks for your reply, it has confirmed for me that I am in the right area and that is huge.
It's been clear now for the last few messages that "you're missing something". Not encouraging, and I'm glad I'm not you .
I will follow with great interest for the followup and hope you find the missing information! As you say, it is extremely unlikely that you're the first to hit this problem, fifteen odd years later, so where is that missing information!??
From reading this, and the fact that I also have the 3-2 and 2-1 issues that's seriously annoying me, I might have to do the same thing eventually. And if you're right in your conclusion, that the industry just "wings" it and hopes for the best is not encouraging!!
I have the 55, which we know is different from the "other" 722.9 gearboxes. Stronger, and if I remember correctly, different gear ratios inside. And software.. If you have issues, I'm bound to have even worse so hope you figure it out.
.I will follow with great interest for the followup and hope you find the missing information! As you say, it is extremely unlikely that you're the first to hit this problem, fifteen odd years later, so where is that missing information!??
From reading this, and the fact that I also have the 3-2 and 2-1 issues that's seriously annoying me, I might have to do the same thing eventually. And if you're right in your conclusion, that the industry just "wings" it and hopes for the best is not encouraging!!
I have the 55, which we know is different from the "other" 722.9 gearboxes. Stronger, and if I remember correctly, different gear ratios inside. And software.. If you have issues, I'm bound to have even worse so hope you figure it out.
Yeah, it's frustrating. What I am missing is the freeplay spec for an 8 disk B1 and an 8 disk K1. Those are specs that Mercedes is supposed to supply. That is where this entire problem comes from.
I just checked the SLK 350 Models prior to mine (2005 etc) and I get the same specs from Mercedes, ie, missing specs for people that have 8 clutches. I then went all the way up to 2012 and they get even stranger from there and harder to read.
I don't know what to say or think anymore. I will ask the Russians as they seem to have a LOT of experience with the 722.9 and do things with it that are not done here (like replacing the bushings on the planetary gearsets).
I just checked the SLK 350 Models prior to mine (2005 etc) and I get the same specs from Mercedes, ie, missing specs for people that have 8 clutches. I then went all the way up to 2012 and they get even stranger from there and harder to read.
I don't know what to say or think anymore. I will ask the Russians as they seem to have a LOT of experience with the 722.9 and do things with it that are not done here (like replacing the bushings on the planetary gearsets).
@marvin-miller
In addition to @Dave2302 's info some more info (including both pdf's from Dave) can be found here . But I could not find the specs you require in them.
Also contains a presentation on the 722.9 from some ATRA guy. An email adress for questions is supplied. No idea if the address is still valid but you could give it a try.
In addition to @Dave2302 's info some more info (including both pdf's from Dave) can be found here . But I could not find the specs you require in them.
Also contains a presentation on the 722.9 from some ATRA guy. An email adress for questions is supplied. No idea if the address is still valid but you could give it a try.
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