Author Topic: Bad Upshift on light Throttle (Auto)  (Read 3158 times)

Paul & Dolly

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  • i Car
Bad Upshift on light Throttle (Auto)
« on: August 17, 2016, 20:14:02 »
Light Part Throttle Upshifts became variable at low speeds, rpm increased before gear changes 2-3.

After consulting Tech Manual here,I investigated and traced the problem to the rotary switch on the throttle body,
operated by the throttle linkage.

A Jo Alexander post ( Rough Shifting ) there indicated the switch should be make or break with rotation, mine was make and semi-make !
so defective.
When dismantled it was apparent that the internals were gunged up and partial contact was being permantly made.
After cleaning and re profiling the contacts, & refitting, normal light partial throttle upshifts returned.

Another example of how useful this brilliant site is.

Thanks

Paul
Paul (located in Cardiff - Wales - UK)
1967 Early 250 SL (Auto) White
Mitsubishi i Car
Toyota RAV 4  Hybrid AWD
1936 Alvis Firebird (Gone............)

TheEngineer

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  • '69 280SL,Signal Red,
Re: Bad Upshift on light Throttle (Auto)
« Reply #1 on: August 17, 2016, 22:02:50 »
That is a very good observation! The proper operation of that switch is very important. I was so disgusted with my rough upshift that I considered installing a newer model transmission. They fit fine, you know. But I adjusted the switch and now the car runs perfect.
'69 280SL,Signal Red, 09 cam, License BB-59U
'67 230SL, 113042-10-017463 (sld)
'50 Jaguar Roadster XK120, #670.318 (sld)
tired engineer, West-Seattle,WA