116 Transmission Help
 

I got a 79 300sd that was shifting hard. The vacuum gizmo atop the ALDA was plugged so that got replaced. Now the shifting is very sloppy. There's a slip between 2nd and 3rd. 1st - 0-5pmh, 2nd 5-30mph, 3rd 30-35mph and 4th >35mph.

I've adjusted the cable/rod atop the valve cover every which way, and the only thing that changes is that it kicksdown to 1st quicker from a stop.

Previous owner said they replaced the "#2 solenoid"?

Please give me some guideance as I'm going nuts.

Jason

You've got too much vacuum going to the transmission. The VCV on top of the ALDA controls that vacuum in proportion to the position of the accelerator. If you remove the vacuum line going to the transmission from the VCV, your shifts should become stiff or even harsh. If that happens when you remove it, you will need to look at the transmission vacuum thread, put a Mity Vac in line with the vacuum line from the VCV to the transmission and make the adjustments necessary to get the appropriate shift.

Thanks Kerry. Would it be safe to assume that I can just crank down the transmission vac. mod.(clockwise) and see if that eliminates these soft, early shifts?

I suggest you look at the shop manual before making adjustments. The vacuum on these is modulated to simulate levels seen in a gas engine so the tranny "knows" the load on it. Chances are someone who didn't know what they were doing removed part of the system and what you have now is full vacuum going to the modulator which is why you are getting slipping. No vacuum means firm late shift and too much means soft, sloppy slip. The key is getting the vacuum level right. Some cars use valves on top of the valve cover to control it and some use a valve on the throttle linkage. I can't recall which your car has but once you find out from the manual what's supposed to be there you can make it right. DON'T ADJUST ANYTHING UNTIL YOU UNDERSTAND IT. If you Tee in a vacuum gauge and the level isn't changing when you step on the go pedal then that's the problem and you can't adjust it away. My guess is the vacuum hoses are connected wrong, very common and easily fixed.