MainePorsche

Correct. The Control Pressure Control cable (Bowden cable) affects timing of the shifts. The Pressure Modulator key adjuster affects the harshness of the shifts. Do a degree, I adjusted my Bowden for my style of driving. After I installed my 'new' Greg Brown transmission, I took a 7 & 8mm wrench on the road with me and adjust the Bowden tension until I felt it was perfect (NOTE - the throttle cable tension was already set). I then adjusted the Pressure Modulator with the key by 2 or 3 notches which is only a quarter revolution at most (you do want to minimize adjusting this). My transmission shifts like butter.
Below is a post I gave to someone back when. Stan gave the original to me, and it is worth its weight in gold.

https://rennlist.com/forums/10497105-post2.html

L_perm

MP,
When you adjust the modulator, is clockwise smoother or harsher?

Thanks,
Louis

MainePorsche

Louis,
It is CW to smooth.
Modulator is set at the factory. Be sure you are optimal with ATF level and Quad cable adjustments before using the Modulator to fine tune. Keep a record of how many notches you've turned it so you can reset/readjust accordingly. Don't *****-nilly this thing. You want to optimize the aforementioned matters and use this only for fine tuning if you have to.
Craig

Mrmerlin

FWIW turning the modulator key way will change the operating pressures in the transmission,
this should only be done with the proper gauge set installed so that you dont set the running pressures too hi or too low

MainePorsche

The Modulating Pressure can only be measured with the car in motion. The Working, or Operating, Pressure is the only pressure that can be measured when the car is up. Excessive adjustment of the Pressure Modulator key is tempting, but can result in extraneous band wear.
On the green Pressure Modulators there are 5 notches for the key in one complete revolution. One complete revolution results in a 6 psi change in Modulating Pressure. The Modulating Pressure is derived from the Operating Pressure, thus changes in the Modulating Pressure will result in a change in Operating Pressure.

L_perm

Thanks guys. I'm not sure I need to adjust at the modulator. I just wanted to know in case. My tranny is pretty smooth, but I think it could use some cable adjustment. I'm going to start at the top with the throttle, butterfly bowden, tranny bowden, cruise cable reset and go from there. My tranny was given a BG flush last July, and my ATF is good.

MainePorsche

Here are some pdf's which I've found helpful for transmission work. Save them - they're good.

http://www.w124performance.com/docs/...722_repair.pdf

http://www.w124performance.com/docs/...2_Mitchell.pdf

L_perm

These are great. Thanks Craig.

Hobibill

Good info.

Captain_Slow

UPDATE: The leak at the Bowden Cable fitting is fixed. Turns out the Bowden cable didn't need adjusting. The PO had placed sound insulating foam under the original Porsche carpet, and some nice Porsche S4 floor mats on top of the carpet. The thickness was hindering depression of the kick down switch.

NOTE: When finished with the Bowden cable O-ring replacement, I carefully filled the reservoir with ATF to just below the full line (engine running, trans in neutral). I've driven it about 200 miles since completing this job. I've had some abrupt and delayed upshifts over the weekend, so yesterday I checked the fluid level and found it below the minimum line. Filled it to the full line and the trans is silky smooth again. I don't have any evidence of leaking (other than a few drops from the TC seal after shut down....with zero evidence of ATF being blown rearward while driving). I'm assuming that the car needed to be driven a bit before the true ATF level will show. I had lost about a quart of fluid while the car was up on stands for three weeks waiting for me to replace the O-ring.

mickster

Hmmm...I bet that's the source of my leak after rebuild-that white part is cracked. I have a replacement bowden cable and plastic housing; will order an o-ring.

Thanks!