Author Topic: Transmission Pressure Switch - any special installation tips?  (Read 3780 times)

jedwards

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I have now acquired the 2 used but functional Transmission Oil pressure switches  that I have been chasing for some weeks, and was wondering if there are any tricks or traps to be watchful about when removing the old ones and installing the new?
I understand that this procedure is a fairly familiar one to member of this august forum, so any pre-emptive help or advice would be greatly appreciated.

Benz Dr.

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Re: Transmission Pressure Switch - any special installation tips?
« Reply #1 on: January 06, 2016, 02:46:29 »
It should be fairly easy. Make sure you have two good seals on each side when installing the banjo bolt.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

ctaylor738

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Re: Transmission Pressure Switch - any special installation tips?
« Reply #2 on: January 09, 2016, 18:32:37 »
I know I sound like the mad scientist, but I suggest using a relay to power the CSS with the pressure switch providing the ground signal to the relay.  That way the pressure switch only handles a fraction of the current needed to power the CSS.

Chuck Taylor
1963 230SL #00133
1970 280SL #13027 (restored and sold)
1966 230SL #15274 (sold)
1970 280SL #14076 (sold)
Falls Church VA

wwheeler

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Re: Transmission Pressure Switch - any special installation tips?
« Reply #3 on: January 09, 2016, 19:41:54 »
No that is actually not crazy. Big solenoids draw a lot of power and can burn small switches out especially those that cycle frequently.

I had an issue with my venturi throttle switch burning out in a few months because of the current through the delicate points. The Auto trans solenoid is a big one and the venturi switch is CONSTANTLY being opened and closed because of the action of the throttle. I installed a relay and presto....no more problems. Should have had one on there from the factory. Maybe old wires and connections are part to blame.
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

jedwards

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Re: Transmission Pressure Switch - any special installation tips?
« Reply #4 on: January 10, 2016, 00:13:51 »
That is a very sensible suggestion wheeler. I am sure I have a couple of spare relays around so will give it a go and report back.
Many thanks for all the help.