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PointedThree :  Vans, Trucks, SUVs and Other Forums : W164 & W166 M-Class : 722.9 Transmission - Acceleration Lag

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722.9 Transmission - Acceleration Lag
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Posted 8/14/2008 7:43 PM
DUTCH
Administrator Doppelgänger




Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
5000
722.9 Transmission - Acceleration Lag

Had the DTB done yesterday to fix the acceleration lag; and I can see only a miniscule, if any, improvement in the lag. I also ended up with an even harder 2->1 downshift out of the deal.

There is new software in the works to fix the hard 2->1 downshift in all 722.9 transmissions on the 642 motor. It's already been released for all models except the 164 and the 251. That part of the new software is to be available later this Summer or early Fall.

In the mean time there is a new ATF 4134 (spec 236.14) P/N: 001-989-68-03-10 that is being recommended for all 722.9 transmissions. It it is supposed to run cooler, which might be a help for that hard 2->1 downshift; since on mine, it always seems to be worse when the weather and engine/transmission are hotter.

Price on the old ATF 3353 (spec 236.12) was/is $15.00/liter. The new ATF 4134 (spec 236.14) is priced at $32.50/liter. Ouch!

I'm scheduled to change to it and a new filter (40,000 miles on the truck) next week Wednesday. I'll let you know if I see any improvement.



Attachments
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Attachments slowaccel.pdf (67KB - 15 downloads)
#129292
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Author
Posted 10/31/2008 10:13 PM
dmcginn2
Regular


Date registered: Apr 2007
Location:
Vehicle(s): 2007 ML 320 CDI
Posts: 61
50
RE: 722.9 Transmission - Acceleration Lag

So how did the new transmission fluid work out?

I am due in about 9k miles.

I have a different issue with my trans...it seems to not want to shift into 7th gear when I am doing 60 mph when I go to work in the mornings, or leave it sit for a while. I wonder if this service will help that out.

Incidentally, that will be the last time I take my vehicle in to the dealer to pay for $200 oil change I can do myself. Plus whatever they charge for the transmission service.
#135072 - in reply to #129292
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Author
Posted 11/1/2008 6:43 AM
DUTCH
Administrator Doppelgänger




Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
5000
RE: 722.9 Transmission - Acceleration Lag

dmcginn2 - 10/31/2008 10:13 PM

So how did the new transmission fluid work out?

I am due in about 9k miles.

I have a different issue with my trans...it seems to not want to shift into 7th gear when I am doing 60 mph when I go to work in the mornings, or leave it sit for a while. I wonder if this service will help that out.

Incidentally, that will be the last time I take my vehicle in to the dealer to pay for $200 oil change I can do myself. Plus whatever they charge for the transmission service.


See here:

http://pointedthree.com/disc/forums/showthread.php?tid=12372&mid=12...

After driving it for a while though, it really doesn't seem to have helped as much as I thought right after it was done.

That new fluid - ATF 134 - is now the specified fluid for both the 722.9 and the 722.6 transmissions. Beware of your dealer's pricing. Two of the dealers in Atlanta want $32.50 and $37.00 per liter for it. MB List Price is $17.00 per liter. From the right dealer (none in Atlanta) it can be had for about $14.00 per liter.
#135088 - in reply to #135072
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Posted 11/2/2008 9:47 AM
dmcginn2
Regular


Date registered: Apr 2007
Location:
Vehicle(s): 2007 ML 320 CDI
Posts: 61
50
Re: 722.9 Transmission - Acceleration Lag

Well, I guess I will have to suck it up for this 40K trans service.

I did look in my book that came with the car, and it doesn't' mention changing out the trans fluid again after 40k.

I hate not being able to work on my own stuff though.

On the 60 mph trans issue I am having. I figured out that if I bump up the cruise control to 61 mph it will upshift and then I can drop back down to 60mph and it's stays in 7th. Very odd.
#135171 - in reply to #135088
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Author
Posted 11/3/2008 6:33 AM
DUTCH
Administrator Doppelgänger




Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
5000
Re: 722.9 Transmission - Acceleration Lag

dmcginn2 - 11/2/2008 9:47 AM

Well, I guess I will have to suck it up for this 40K trans service.

I did look in my book that came with the car, and it doesn't' mention changing out the trans fluid again after 40k.


Check out page 64 of the Maintenance Book.



(ATF_Change.jpg)



Attachments
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Attachments ATF_Change.jpg (95KB - 21 downloads)
Attachments ATF_Change.pdf (139KB - 15 downloads)
#135265 - in reply to #135171
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Posted 11/10/2008 5:24 PM
dmcginn2
Regular


Date registered: Apr 2007
Location:
Vehicle(s): 2007 ML 320 CDI
Posts: 61
50
Re: 722.9 Transmission - Acceleration Lag

Exactly.
#135824 - in reply to #135265
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