W110 W111 W112 Sedan, BENZ AID - COMMON QUESTIONS AND ANSWERS

Will the tach from a 420SEL work in a 1983 SD? Because I have the rear axle of a 420 in my 83 300SD I am using the speedometer from the 420 for accurate reading already. The original tach and clock are not working I know that the plug in is different, but are there any other issues to consider?

Can the flex discs be replaced without removing the drive shaft? Do you sell the discs with instructions to fit this car?

I have a 76' 300D that I have to back off of the gas pedal to make the shift from 2nd to third. The 2nd to third shift will NOT happen unless I cause it with the gas pedal. The 3rd to 4th shift works better and will sometimes shift by itself without me backing off of the pedal. All the shifts happen in the indicated spots on the speedo, more or less, the kickdown into 1st operates just fine and the trans goes into drive and reverse with little to no hesitation. Trans has aprox. 175K on it.
Is there a linkage I can adjust to fix this, or is it a sign of my trans slowly going? To my knowledge this year trans did not have any vacuum hook-ups.

On the 80 300sd that I just purchased it had a shutoff valve between the engine block and the tube coming from the auxillary water pump. I have replaced the thermostat and coolant but I was not getting any increase in temp on the hose leading to the aux. pump. I know this has something to do with the climate control so I wanted to see if there was a blockage or if the valve was frozen shut. I used a thermo gun to see the different temps. When I reconnect3ed the hose without the valve there4 was no coolant flowing out so I assume this is where I mite have had a air pocket.