GregBBRD

Great!

This tells us that the differential is all in one piece and the gearshift selector is actually moving things, inside the transmission.

If you have verified that the torque convertor is actually attached and spinning when the engine spins.....and that the fluid level in the reservour actually "drops" when the engine is started....

It is now time to remove the oil pan and see what falls out. I'm betting there will be spring debris from reverse piston....

GregBBRD

Modulator could have completely failed and there would still be drive in some direction, me thinks.

MainePorsche

Greg,
Will drop the pan and see what flies.
First I'm going to look at the modulator's ability to hold pressure, and the line to it. It's a quickie.

MainePorsche

Well, one issue that's present is the modulator does Not hold vacuum. Not even close. The status of the adjuster cap is good, and is not the cause.

Kevin in Atlanta

I have a good one if you need it. I have no use for it. I just tested it.

GregBBRD

Interesting. One would think, with a modulator with a blown diaphragm, you'd have sucked up a whole bunch of transmission fluid. Yet you think it has plenty?

MainePorsche

I thought it odd to that my level was a little low when all warmed up. I drained converter and pan last year at end of summer, and leveled it nicely. I have never had any leaks.

76FJ55

Just a quick verification, when you performed the last run test of the trans did you have tg e emergency brake applied or rekeased? And did you just run the test at idle or did you give it any throttke?

GregBBRD

You want to put a couple quarts of fluid in it and try it, before you pull the pan?

MainePorsche

The E brake was not applied.
I checked at idle and with throttle. Did get the small amount of rotation with throttling, but the rotation did not last long. This was even with constant throttle.

MainePorsche

I did top it/level it on a warm engine with a 20 min idle (obviously couldn't warm the trans. by driving). This was done before any testing of function.
Before I pull the pan, I'm waiting for gasket, filter, new modulator to arrive.

namasgt

Go under the car look behind the converter (where the converter main seal seats) if you see any traces of oil, then you have an oil leak. It can be gradual enough that you wouldn't notice it....When the level gets low the car starts shifting hard, then after a while you will hear a humming or whistle sound when you are stopped and the car is in drive. Then enough will leak out until eventually it no longer engages. At this point the oil pump bushing(s) could be damaged from lack of oil...

76FJ55

I'm still baffled by the early issue with park not holding the car stationary.

Now that you've tried running it in gear and getting no drive it may be interesing to get your son to help run the experiment of rotating the rear tires with the car in park again.

MainePorsche

Thanks for the input.
It's late and I just got home. Will try to look tomorrow.
I have looked at this periodically and saw no leak. When I said the level was low, it was only a 'smidgen' low from where I last remembered it was. No hum or abnormal sounds heard. I had the hard shifting even before I drained and changed the fluid from the converter and pan. At that time I was flying 'solo' and not connected to Rennlist, and had no idea to check vacuum at modulator and its line regarding the hard shifting.

MainePorsche

So am I at this point. Was rolling in the parking lot in Park, and when I was towed home. On the flat bed (was hoisted via rear tow ring) I began to roll when bed was beginning to tilt down. I was in Park, and had to brake. I then put it in Neutral and waited for full tilt so I could roll it into the garage.