[W126 Coupe] High RPM Shifting Problem

[Sharan Bains]

You can start be having the following checked :

- kickdown solenoid on the transmisson : if this is faulty you will get some 
funky shifting/non shifting patterns

- fuel pump relay : this controls the rev limiting function, unlikely to be 
the culprit though if it is only happening in one particular gear

- finally if none of the above, then it's likely the valves controlling 
third - 4th upshift in the transmission valve body that are at fault.

Could be another issue i haven't thought off, but the top three come to mind 
first.

talbir


>From: "Demetre at Eurospec" <demetreandreou at rogers.com>
>Reply-To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>
>To: "Mercedes Coupes Mailing Lists" <mbcoupes at mbcoupes.com>
>Subject: Re: [W126 Coupe] High RPM Shifting Problem
>Date: Sat, 29 Apr 2006 18:14:01 -0400
>
>High RPM Shifting Problemhey barry demetre from toronto iv got an 89 euro 
>as well imported from japan i had the same problem turned out to be a 
>tranny problem i rebuild it cost 1500 canadian
>   ----- Original Message -----
>   From: Barry Sharp
>   To: mbcoupes at mbcoupes.com
>   Sent: Thursday, April 27, 2006 7:52 PM
>   Subject: [W126 Coupe] High RPM Shifting Problem
>
>
>   Greetings from the wet coast (Vancouver, BC).  I have a 1989 560SEC Euro 
>model with about 106,000 km.
>
>   I've noticed a problem with the transmission not shifting up at maximum 
>rpm.  Last weekend, when passing another vehicle doing about 90 kph, I put 
>the gas pedal to the floor and the transmission shifted into second.  As I 
>passed the other car, I got up to around 120 kph and the car started 
>jerking.  I backed off the gas and the transmission shifted into third.  I 
>figured that it was a rev limiter kicking in.  I was quite concerned, so I 
>thought I'd check it out.  It didn't matter whether the transmission was in 
>Economy or Standard mode, it would not shift into third with full throttle 
>at 6000 rpm.  The rev limiter kicked in and the engine started missing very 
>badly.
>
>   I also tried a full throttle shift from third to fourth.  Same problem.  
>At about 200 kph with 6000 rpm and full throttle, it would not shift into 
>top and the limiter kicked in.  Having the car shaking you about at 200 kph 
>is quite disconcerting.  It felt like the drive train was shaking itself to 
>pieces.
>
>   Other than the high rpm shifting issues, the engine and transmission 
>seem to work perfectly.  Any thoughts as to what the problem is and should 
>I have it seen to?
>
>   Thanks in advance for your help.
>
>   Cheers...Barry
>
>   1989 560SEC 106,000 km
>
>
>
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