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‘06 U400
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Discussion Starter · #1 ·
Hi there, in the final stage of getting the hydraulics sorted on the blower to go on the front of the mog (will post pics in another thread once done) but a problem has presented itself this morning for the guy who was driving it:

Wont change above 4th! Will show 5 as selected on the display but wont go into 5th when depressing the clutch.

Any suggestions from the brains trust?

Nothing has changed on the truck in the past week and its been driven the past 5 days.

2006 U400 - Based in Japan.

Thanks in advance!

I‘m not on site presently but the only thing I can spitball is that the oil might be getting a bit cold and impacting the auto shift….We are in Northern Japan so overnight temps heading close to zero (though its been colder last week and no issues)
 

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Discussion Starter · #2 ·
Forgot to add, he said it also takes a while to go into natural (when that happened)
 

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Discussion Starter · #4 ·
Cheers. I don’t know what’s in it now, it’s what it came with. Haven’t had it long. No clicks or noises. Just won’t change when clutch is pushed.
Excuse my ignorance, what’s reteach the transmission?
 

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Discussion Starter · #7 ·
Thanks guys. I’m not at the machine but will get back to you with answers when I am. Appreciate it!!
 

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Discussion Starter · #8 ·
from the guy driving it earlier “Sometimes it goes into neutral other times it shows it trying to change but just clicks if you release the clutch”
 

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Discussion Starter · #10 ·
And no problem with shifting between 1 and 4? What about working gears? Can you shift in those?
All word of mouth (or text actually) from the guy on site, but as i understand it, no issues gears 1-4. As for working gears, I asked him to check that and he will report back.


Thanks to all for the feedback, given me plenty of food for thought. Will report back as soon as I Have more. It actually goes into the paint shop in 24 hours so we wont have it for a week or so I think.
 

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Discussion Starter · #11 ·
Update. Does the same in working gears also. Not above 4th gear
 

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Discussion Starter · #12 ·
I would definitely test that transmission fluid.
SAE 75 W-80 (235.41)
I'm thinking...might be a solenoid for range change...
When you shift from 4th to 5th does it go to neutral or does it stay in 4th?
Thanks for that info. I was googling options to order since I figure we may as well change it anyway and came across what I THINK is the document that you referenced this to but 235.41 seems blank of any info (well if I am reading it correctly)

BENZ Gear Oils

Not questioning your advice, just trying to wrap my head around the way things work with their manuals so I am not posting my questions all the time! Is there a better listing for this info that that one. I dont have the operating manual that I bought with the vehicle with me right now so trusting the interweb……

And lastly….. I am assuming the SAE75W-80 is the way to go but then there are variants and reading through a number of posts and other info online - it seems GL-4 is the correct variant to use? If so, I can luckily find it online!

Amazon oil GL4


Attached are pics of the VIN plate etc

Font Rectangle Gas Technology Nameplate


Motor vehicle Font Nameplate Gas Automotive exterior
 

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Discussion Starter · #14 · (Edited)
I don't claim to be an expert on that topic, so I'm always open to new ideas.
I was informed/advised about the UGN (U300-U500) transmission fluid not long ago by M37 Charlie, another U500 owner and member of this forum.
MB changed its transmission fluid specs not long ago from 235.4 to 235.41, which means from 75W85 to 75W80.
Yes, it looks like the stuff you're citing should be right for your tranny.
75W-80 GL-4
Awesome. Appreciate it. Just trying to wrap my head around where to source the latest up to date info, and avoid looking like an askhole that’s always on here seeking info that is readily available!
 

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Discussion Starter · #15 ·
UPDATE

Just had an hour with the vehicle.

I tried the MINOR TEACH that yarr kindly posted. Only point of difference might be that mine (I assume from the MB site) is 405.103 vs the teach being for 405.210/230

Mine is EPS only

Step 1)Performed the MINOR TEACH - ONly point of note, the final step takes a while to complete its process, numerous pneumatic sounds etc, which I assume are normal.

Step 2) Drove it and magically…it shifted into 5th and above. Thought it was solved.

Step 3) Drove again - problem reoccurred.

Step 4) MINOR TEACH again

Step 5) Issue reoccurred

Step 6) MAJOR TEACH - halfway through got GS31 error so didnt continue. Turned ignition off and did a MINOR again

Step 7) Tried a few runs. Also in working gears. Issue continued to occur.

Can’t load videos here so here are the IMGUR links to the times i videoed it:



Only points of note, when it did go into 5th, it seemed to be quite “clunky” and when going from 5th into N (by itself) there was also a small transmission jolt.

Mild day (18 deg C)
Vehicle was moved earlier in the day
It will either
a)Go straight into N when trying for 5th
b)Beep and display 4 with 5 preselected
c)Show 5 but actually be in N, i.e. release clutch and nothing engages even though it says 5

Thats about all I can add for now.
 

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Discussion Starter · #16 ·
Don't remember if you have EAS transmission but I think so.
Try minor first.
If you only have EPS like let me know.
Oh, I believe Charlie would ask about the voltage on your battery, which apparently could be an issue with EAS as well.
Just confirming your earlier question - EPS only
 

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Discussion Starter · #18 ·
My wild guess is the air solenoid for the range shifter is bad. Are there errors stored in the FR and GS parts of the menu on the dash, after trying to shift but before turning it off?
By the way, Atlas in Germany and Atkinson Vos are both selling the transmissions (UG100-8/9.57) with a floor shifter. But it most likely still relies on air shifting for the range shifting.
Iain in Brisbane just put one in his U1250.
Yarr, remember everything on his is 24v - no voltage converter or pair of motorcycle batteries needed. And we both know everything would go wacky if he lacked 24v, not just range shifting.
Thanks. Yes it seems like it’s TRYING to change to 5 but something just not quite getting there, then it reverts to N (either displayed, or 5 displayed but still in N) or just stays in 4.

I was getting the hairy eyeball from the paint shop guy as I was driving around with no doors/mirrors etc or number plates, and he wanted it in the shop, so I didnt have time to check the error codes, but will maybe get the chance to tmrw.

What’s the best source for maintenance manuals on these? I tried googling around and not much came up.
 

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Discussion Starter · #23 ·
It might be that range change just needs adjustment.
Here is the procedure:
Awesome. Thanks. Just about to hit the bunk but I’ll read that tmrw. Where do you guys get the workshop manual from? I’m currently downloading one (10gb) that I just purchased. Hopefully as detailed as the info you guys kindly provide!
 

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Discussion Starter · #27 ·
Re manual, I used to use a CD or DVD disk, but now it’s downloaded onto a Microsoft Sync and also on a little “dongle” with a USB male plug sticking out. I wonder if I can email the thing to you? I will look later as to its “size”.
Cheers, I will send you a DM about it - Maybe Dropbox? Currently looking at AUTEL and other systems and compatibility! I’m sure I was going to bed 90 min ago…!
 

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Discussion Starter · #30 · (Edited)
Well, I got the machine back from the spray shop (attached) and checked the linkage length - had to make a dummy guide as my calipers can’t fit in there but it’s 127 plus or minus maybe 2mm max.
I did a minor teach, then a major, last step in both instances takes quite some time (more than 30 sec)

through the various motions of driving, teaching etc the errors that came were GS11 GS17 and “( n )” ~no spaces, but it creates an emoji if I type it exactly~

video attached you can hear what I believe to be the pneumatic solenoid actuating

I’m pondering tightening the linkage 1mm just to see if that leads to success - side note it’s in a bitch of a location.


Tire Wheel Sky Cloud Vehicle
 

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Discussion Starter · #31 ·
I would definitely test that transmission fluid.
SAE 75 W-80 (235.41)
I'm thinking...might be a solenoid for range change...
When you shift from 4th to 5th does it go to neutral or does it stay in 4th?
Also looking at changing the fluid as the stuff I ordered has arrived. I hope it’s an easier task than the linkage!
 

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Discussion Starter · #32 · (Edited)
further update. I changed the linkage spacing about 1-2mm either side of its first position. Made no difference to the problem.
I filmed the linkage during a minor teach and as you can see from the video, it’s moving no prob.

when I go into the faults section after getting the various GS faults mentioned earlier, I find the GS0511 as shown.
Going to start digging through the manuals I was kindly sent and see what else springs to mind!




Sky Automotive lighting Cloud Vehicle Gauge
 

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Discussion Starter · #35 ·
The GS (actually all) error codes should be 2 capital letters, like GS, referring to which computer system. Then 5 digits, not 2!!
The “n” in parentheses refers to the computer controlled fixed rpm fast idle switch, which for normal driving should be OFF. I use it rarely for stuff like running my hydraulic generator at 890 rpm for example. When ON the truck is likely undrivable, at least in a normal way. The switch is on the panel between the seats.
Hmmmm… Seems I only get 2 digit codes, e.g. 24 if the park brake isnt on when I do the teach and the others are 21 or 17 usually. I bit the bullet and got the Unimog guy in from the city (1 1/2 hours away) and he ran the diagnostics on it and it came up fine. He then started swinging spanners on the forward end of the transmission. he had to leave before finishing but when I last saw him he said he was going to do some more research and some back soon to continue, as well as change the trans oil. - Fingers crossed.
 
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