An update for those who have been helping me work through the upshift issue.

I installed a Sonnax rebuilt valve body, which included solenoids, and I also bought an OEM Mercedes conductor plate. No dice. It still won’t upshift after a long drive on a hot day, followed by stoplight to stoplight driving. As I come into a stoplight, I can feel the car downshifting at about 1500 rpm. It then takes until about 2500 rpm to get it to upshift again. If I accelerate to 2000 rpm then let off the gas pedal, it does not upshift either, it just Jake brakes its way down.

I won’t list all the things I’ve tried, but the list is extensive. I don’t know where I’ll go next, but I’m probably going to let it lie for the time being. Maybe something will come to me (or one of you). It seems like the problem has to be mechanical (not electrical), because until I drive 1-2 hours down the Interstate on a hot day, the car runs, drives, and shifts perfectly fine. It’s ONLY after a long drive on a hot day that this problem arises.

Thanks for all the ideas up to this point. Let me know if you ever come up with a new idea we haven’t tried.

 

Do you have a way to monitor your transmission fluid temperature while driving via a scan tool?

I’m wondering if the repair shop flushed out your transmission oil cooler when they rebuilt it? Not that you had a major failure to clog your cooler.... just an idea.

 

I don’t have a way to do that, but I am thinking about coordinating with a shop to try it. I think it’s odd that I wouldn’t see a “high gearbox temp” warning if tranny temp was an issue. But, everything is on the table so I’m not ruling it out.

I don’t know if the cooler was flushed during the rebuild. I installed a brand new radiator during the restoration process. It was about 1.5 years after the restoration that this transmission issue surfaced. It is possible that the cooler got plugged when this happened, although there was never a sliver of foreign matter or metal pieces in the pan. Again, you’d think I would see a gearbox temp message if it was not cooling properly.

How does the transmission decide to shift? Does the TCM read the inputs and say “shift up” or “shift down. Or does the TCM read the inputs and say “choose third gear”. Something is telling the tranny to downshift as RPM’s decrease, and telling it not to upshift until 2500 rpms are reached WHEN ITS HOT. And whatever is issuing those orders believes it to be right, because there are no gearbox messages, no check engine lights.

My next step may be to set up an appointment at a shop and have them ride with me while the computer is hooked up. The shop I used for the ECM programming is 2.5 hours away, so by the time I get there, the shifting fault will be active. I will keep the car running, have them jump in the car, and we’ll go for a drive while studying the computer for codes, temps, errors, etc.

Might have to wait til next summer to make sure it’s a hot day while I travel to the repair shop. Just thinking out loud. Thanks for the suggestions, keep them coming!

 

You've cleared the adaptions? I'd hate that question just as much if I was in the same shoes after all that work but it's worth asking.

And not the method where you put the key here and there and pedal to the floor and all that. Actually see the adaptions zero out on a system that can see those values. After a valve body repair it does mention to reset them I think.

These transmissions are so durable it's crazy. You'll find the answer soon.

 

I don’t think so. But I did swap the ECM, which required an immobilization setup, and I replaced the TCM, which was plug and play. Neither of those things made any difference. That being said, is there something else that stores the adaptations that would need clearing? Thanks for the suggestion.

 

Have you had the torque converter checked?

 

The torque converter was replaced with the transmission rebuild (supposedly). But everything is on the table, so thanks for the idea. Not sure how I would test that, other than swapping it out, which I may have to figure out how to do eventually.

 

I don't think the torque converter, if it has any problem, will affect the shifting points. These are controlled, I believe, by the TCM, Conductor Plate Sensors and the Valve Body. Probably also by the ECM in some way.

As I cannot remember all info from your earlier thread, are you using the correct ATF in the gearbox?

Another thing that you can put "on the table" is the Sport Mode. Perhaps, for some reason, the Sport Mode engages itself when the things get hot. When your gearbox goes into later shifting, try switching the Sport Mode on-off a few times and see if it makes any difference.

 

Well I THINK I’m using the correct fluid. I’m using Ravenol M9. Meets 236.10 to 236.14 specs. I don’t recall where I found what the required spec needs to be, but I was pretty comfortable at the time that Ravenol M9 was ok.

I do not know what fluid the shop used when they rebuilt the transmission, but the result has seemingly been the same.

Is the Ravenol M9 ok?

I have played with sport mode a lot, and it doesn’t make any difference if I turn sport mode on or off at any speed or rpm. When this problem is active, it will not upshift until around 2500 rpm, and it will not upshift when coasting in to a stop no matter what I do with the sport mode button, or the gearshift lever. In fact, it downshifts when coasting in to a stop, and does not upshift when I let my foot off the gas to “coast”. It just stays in gear and uses the engine like a Jake brake.

As a clarification: I can downshift the tranny by manually using the gearshift lever. But even when I put the lever back in a higher gear it will not upshift unless the rpms are above 2500. So I can slap it from 5th to 4th, but if the rpm’s don’t go up to 2500, when I move it back to 5th, it just stays in 4th. All gear selections are like that. If I’m going 75 and put it in 4th, then back to 5th, it will shift to 5th right away because the rpm’s jumped above 2500.

Prior to getting hot, the car shifts like a dream, smooth and correct all the time. But drive 2 hours down the interstate on a hot day, and boom - the issue surfaces and can only be corrected by shutting the car off and waiting for it to cool. My OBD reader tells me that the engine temp is fine. Seems to run around 190-200 all the time, even when this issue is active.

It’s like a sensor someplace is feeding information to the ECM or TCM, which leads the TCM to change the shift points, but that does not throw a trouble code. It’s like the tow/haul mode on my F150. It uses the engine as a Jake brake (kind of) when pulling a trailer. That’s what this feels like too, and why I mention Jake brakes once in a while. But there’s no tow/haul mode in the Jag.....unless there’s a sensor someplace that detects how hard the driveshaft is being “pushed” when decelerating. Problem with that theory is that I’ve replaced the valve body and the conductor plate, which means that a defective speed sensor would have been replaced. Twice....because the repair shop replaced the conductor plate, and I just replaced it yesterday when I put in the new valve body.

Hmm. I’m stumped.

 

RAVENOL ATF M 9-G Serie

 

I'm not using M 9-G, I'm using M 9 Serie, which says this:

RAVENOL ATF M 9-Serie was developed for use in the newly developed NAG2VSport transmission, 7G-Tronic (Template 722.9 / W7A 700 / NAG2), also for 5-gear transmission (Template 722.6 / W5A 580 / NAG1). It is backwardly compatible for all earlier versions of Mercedes-Benz 4- und 5-gear passenger car transmission (Template 722.3, 722.4, 722.5) in the exception of 5-motion CVT-Automatic transmission (Template 722.7 / ***) of the A-Class (W168) and the Vaneo (W414).

I didn't realize there was a G version. Sorry for not being more clear.

 

Nobody:

Me in the background: *clear the adaptions! Clear the adaptions!*

I had a transmission fault from 3rd to 2nd that was fixed by resetting the adaptions. It's my new go to for anything now. That was 30k miles ago.

 

Haha. Sounds like me with vacuum leaks! I’m not ruling this out, though. It’s possible that a reset needs to be done with a computer capable of doing it.

 

One issue with a bad torque converter is surging and loss of power because the fluid flow is not be transferred.

How a torque converter works...

 

The ravenol fluid you use is not the correct fluid , always use fluid that meet lt71141 specs , bilstein febi have lt71141 fluid 5 liter jug

 

The M-9 Serie (not M-9 G) says it meets 236.10 and 236.12 specs. That being said, everything is on the table here. I would happily be wrong if it fixes my problem.

I was not aware that there was another spec called lt71141. Everything I have researched has said that the fluid in the 722.6 needs to be 236.10. I have no idea how these specs are derived, but does the fluid have to meet BOTH 236.10 and lt71141?

I am willing to try different fluid. Is there a drain plug on the torque converter? The MB forums show that there is one, but I can’t find anything here that says there is a plug on the Jag version.

I would like to explore the fluid question because it makes sense. I know there are thousands of threads on which fluid is correct, but please weigh in with what you’re using, and let me know if there is a drain on the torque converter.

As always, thanks for the input.

Edit: check that...I did find threads that discuss the TC drain plug. Since mine is a 1998, it might have one. I will put it up on the lift and find out as soon as I can. I’ve done so much searching that I forget what I find.

 

How definitive is the information in the link below? It looks to be straight from Mercedes Benz. Although the M-9 Serie fluid that I'm using is backwards compatible to 236.10, MB does not list it among the recommended fluids for 236.10. Instead, they list M-6 Serie, along with a very short list of other brands. I would think that if a fluid is backwards compatible to 236.10, there's no way this could be causing my issue. Comments?

https://bevo.mercedes-benz.com/bevol...236.10_en.html

I'm going to put the car up on the hoist this weekend and see if there is a drain plug in the torque converter.

 

I don't have much knowledge about Mercedes cars and the fluid link. The jaguar zf5hp transmission is well known it need the original zf5 fluid but its expensive so some uses the other brands which meet the exact specs and I think the source of the zf5 fluid and other fluid that meets the exact lt71141 specs are sourced from esso . Check mobil and bilstein I think the bilstein is cheaper. I don't know about the TC .

Ravenol have fluid that's fit the zf5hp RAVENOL Automatik-Getriebeöl ATF 5/4 HP Fluid.

 

Post deleted because I was wrong and corrected by MS.....ty MS

 

There is no relation between ZF5HP and 722.6, completely different transmissions from different manufacturers. The ZFs are manufactured by Zahnradfabrik Friedrichshafen and the 722.6 is manufactured by Mercedes (Daimler AG actually) in Germany and by Crysler Group LLC in the USA.