transmission shift issue

[moose]

Greetings Wise ones,
I have an issue with the transmission in my 36 Sedan. I am running the standard strreet rod set up. It is a Chevy 350 with a Turbo 350. I am running a stock convertor. The trans is shifted via a 72 Chevy tilt collumn.

The issue I have is with it NOT always down shifting to first at a stop. From astand still it up shifts fine. I can get a kick down shift with full throttle okay. It is when I come to a stop that it does not always drop back to first gear for take off. I can manually down shift and continue normally. What do I need to look at or possibly adjust?

Thanks for the help!

Tim

[Crosley.In.AZ]

Do you know what and where the vacuum modulator is?

When you find it at the rear of the trans main case on passenger side.  Pull the hose off, look for fluid out of the nipple.

No fluid in the nipple?  That is good.  IF there is fluid, that is bad.  Replace modualtor

Check the vacuum hose connections at each end, engine side and trans side.

Do you have rubber hose the full length or steel tube?

If the modulator goes bad or there is a leak in the vacuum feed line, the trans often will not drop to first gear at a full stop.

There is a valve behind the vacuum modulator.  Need to verify that moves freely in n out.  Since the trans mostly shifts correctly , that valve should be OK, check it as a precaution in this chase to find the problem.


Any other cause will be internal like the governor or the shift valve in the valve body.

It may b wise to drop the pan for a service change of fluid and look see inside the pan.  Has that been recently done or ever done ?