[W126 Coupe] High RPM Shifting Problem

[Barry Sharp]

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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