Hard shift cluck 2rd gear sometimes. Shift gear valve assembly fault. 140K miles on 1997 Mercedes-Benz C230

Dealer: rough shift only on 3 to 2 downshift. Found transmission fluid dark. "performed short test, found stored code for selector lever is implausible, communication with engine module, and reverse/park lock solenoid fault" <- don't understand this. Normally would recommend a valve body, but mileage is high. Not confident will fix shift issue without cause clutches to slip. Best replace entire transmission.

by in Milpitas, CA on February 29, 2012
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1 answer 4 comments
ANSWER by , March 01, 2012
A flush and seafoam treatment couldn't hurt. $150.00 is better than $4,000 if it works.
COMMENT by , March 03, 2012
OK. Toke to "Elite Mercedes" shop and replace transmission fluid. Fluid was dark. But found no metal or chip or anything funny. It was $270. Test drive. Still rough down shift from 3 to 2. Sigh.
COMMENT by , March 04, 2012
Some of the aftermarket diagnostic tools can cycle the shift solenoids also. Dark fluid is clutch material which normal wears over time. Did they add seaform or some other type of agent to break up the varnish?
COMMENT by , March 05, 2012
Fletcher Jones MB dealer said the problem is Shift Valve assembly problem. Please send me more detail about aftermarket diagnostic tools to cycle shift solenoids? No, "Elite Mercedes" replace the transmission fluid. Did not say anything about add seaform to break up varnish? What is that?
COMMENT by , March 05, 2012
Our diagnostic tools like the GT1, Star, Modis are very expensive. Most larger independents have them. Find a local place and get a second opinion. Worse case scenario is you'll need a transmission but at least you'll know for sure.