Quote:
Originally Posted by CDTurbo001
Since adjusting the throttle linkage and Bowden cable on my '82 300CD the other day, shift behavior is much improved. [1] No more harsh 1-2 and slipping 2-3 - under normal acceleration the shifts are firm
but not violent. However, after having pulled up to a stop in traffic, etc., when it comes time to move again I have to tip just a bit into the gas pedal, wait 1-2 seconds until the transmission seems to fully re-engage first gear, then I can move on and it behaves fine until the next stop. My initial setting for the Bowden cable was where all slack in the cable was out at idle, but no further. Tried 1.5 turns out and that doesn't correct the problem - haven't tested where the WOT shifts are as a gauge of cable adjustment, don't really want to run the engine that hard, that much until I can adjust the valves and check timing chain stretch.
Also, I checked the modulator line for vacuum leaks - held pressure fine. Also replaced the hard lines from the switchover valve to vacuum supply, and to the coupler leading to the transmission; it seemed the multi-connector on the SOV had become hard and was allowing a small leak. Removed the line to the ported vacuum switch/EGR as well. Did not test the vacuum signal from the SOV - as I understand it's supposed to vary with throttle position?
Any insight on what's causing first to partially disengage/slip until the pedal is advanced slightly?
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Quote:
Originally Posted by CDTurbo001
Okay. Does the valve body have to be removed to get to it?
[2]What, exactly, is the B2's function(s)?
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Quote:
Originally Posted by CDTurbo001
Cool, thanks. I've also narrowed down that it doesn't do this when the shifter is in "L", but can make [3] a REALLY nasty noise on the 1-2 shift if you attempt it manually. Does that further support a sticky B2?
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[1] For the record: the transmission is a 4-speed unit that normally starts in 2nd. CDT, since you have not mentioned a 3-4 shift, it just may be possible that you believe the trans to be a 3-speed, since it starts in 2nd.
[2] The B2 piston applies the #2 brake band (hence "B2"). B2 is applied in 1st, 2nd, & 3rd, and released in 4th.
[3] When the selector is placed in L, the trans is placed in 1st. On the actual 1-2 shift, two things occur: a one-way clutch (aka, "freewheel" or "sprag") is overridden, and band B1 is applied. The most likely cause of the noise is a chattering band due to a slow/weak applying B1 piston. A weak B1 apply (low hydraulic pressure at idle) would also be consistent with the "slipping" complaint when starting in 2nd from a stop.
Band B1 is applied only in 2nd, released in 1st, 3rd, & 4th.