Pagoda SL Group
W113 Pagoda SL Group => General Discussion => Topic started by: lurtch on October 29, 2005, 17:21:17
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Hello to all - - My KA4A025 transmission is slipping in all gears. The fluid is topped off and it looks and smells normal. I am troubleshooting using the guage set up described in the BBB (see attachment). In the photo the engine is idling , the trans is in neutral. After a few test rides with this lash-up I have determined that the modulator pressure never rises above the as indicated 7 PSI. A one-half turn IN on the fine adjustment shaft (followed by another trip around the block) made no difference in this operating pressure.The book says that this pressure should max out at around 40 PSI. Another reference text says the correct modulator pre-set pressure with the vacuum line removed should be 58 PSI. I have 7 PSI with or without vacuum - - Do I have a ruptured diaphram?
The guage on the left is hooked up to another test port on the trans which I believe is <BBB> "shift pressure". This pressure rises to 100 PSI when reverse is selected.
My gut feeling is that this transmission is not a rebuild candidate. Any suggestions about what to do next from any of the Pagoda technical expertise gurus ? Regards, Larry in CA
Download Attachment: (http://images/icon_paperclip.gif) test guages.jpg (http://www.sl113.org/forums/uploaded/lurtch/20051029191926_test guages.jpg)
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The modulator pressure determines the working pressures. Modulator pressure should be 41PSI with the vacuum line disconnected. I can't comment on the "other test port" pressure, not knowing where you connected. If your modulator pressure is not to spec. the transmission will slip. Don't drive that way! You can remove the modulator diagphram with the transmission installed. The adjustment screw pushes on a spring, which pushes on the diagphram, which pushes on a pin, which moves a control sleeve. Just a little bit of dirt or even lint from a rag may prevent a control sleeve from moving. They are not kidding when they say:"Don't use rags, use a chamois". A broken diagphram manifests itself by transmission fluid sucked into the intake manifold. Big time white smoke! I have seen that transmissions are advertised as "rebuilt" when all they did was to clean it. I have a drawing of the modulator assy. Best way is to fax it.
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Larry,
Any progress?
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420