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  #1  
Old 03-12-2000, 09:10 AM
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Join Date: Nov 1999
Posts: 26
Any Ideas?
When cruising at 60mph an then kickdown for
overtaking the transmission seems to go into
neutral. It runs almost up to redline before
a gear is selected. It feels as if it is missing fourth. When I manually select between fourth and fifth (and visa versa)
nothing happens.
I had it at the dealership and they billed me $350 dollars to remove according to them a
sticky substance below the selector. The
vehicle operated OK for a week.
Something does not make sense.
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  #2  
Old 03-12-2000, 09:29 AM
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Join Date: Jan 2000
Location: New Bedford, MA USA
Posts: 1,583
Take it back right away and drive it very gently until you do so. Over revving can fry clutches as well as being unhealthy for the engine. Possible cause=vacuum modulator or hanging downshift valve in the valve body.
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  #3  
Old 03-12-2000, 09:45 PM
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Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844

How many miles on it?

I presume that downshift would be from fifth to third? To go to neutral would be difficult as I think both fourth and fifth are additive. Meaning that you are already in third if you remove fifth and fourth. I will have to look at a powerflow chart for fifth gear. In the 722.3 and 4 trannies 3rd and fourth gear are clutches and are additive. The 722.5 might do it differently.

I would suspect a command valve problem in the valve body. How long since the last trans service? Depending on the age I would recommend a additive designed to soften seals and free valves. Lubeguard is a good product.



------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
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  #4  
Old 03-12-2000, 10:01 PM
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Join Date: Mar 1999
Location: Suwanee, GA, USA
Posts: 4,712
I have had to replace 722.5 tranny's with less than 60k on them for this reason. I think, if memory recalls, the sprags were failing internally.

------------------
Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM


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  #5  
Old 03-13-2000, 08:29 AM
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Join Date: Nov 1999
Posts: 26
Steve,
The last transmission service was done around
5000 miles ago. The vehicle has 56k on it.
(Mybe it is a good thing I have the extended warranty on this one)

Deon Smith.
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  #6  
Old 03-13-2000, 08:33 AM
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Join Date: Nov 1999
Posts: 26
Benzmatic,
What is a sprag. (My other car is a manual 964 so my autmatic knowledge is limited).

Can it be replaced pretty quick and with the transmission in the vehicle.
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  #7  
Old 03-13-2000, 09:23 PM
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Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
The 722.5 trans is simular to other Benz transmissions except for Overdrive unit.
There is a control soleniod for 4-5 shifts & its problems have been noted on "RED diagnostic fische" that dealers receive. Sounds like this solenoid is causing your problem. The car has a computer that controls & monitors 4-5 shifts, has the computer been scanned for codes?

------------------
MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. TECH
190E 2.3 ITS RACECAR

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  #8  
Old 03-14-2000, 07:49 AM
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Join Date: Nov 1999
Posts: 26
M.B Doc,
The shop did scan the transmission computer and found some code. They told me the code
was incosistent and they could not replicate.
They do suspect one of the selector switches
is feeding the incorrect gear position to the
computer. They did not have all the parts
so the car is still inop.
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  #9  
Old 03-16-2000, 08:52 PM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
The only switch that could cause a problem is the one in the shifter that is between the 4-5 gate. Solenoid is what usually fixes this problem.

------------------
MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. TECH
190E 2.3 ITS RACECAR
1986 190E 16V
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