[T3] Auto shift issue

[Jim Adney]

On 11 Sep 2015 at 10:26, Tim Keohane wrote:

> The tranny will not shift till I hit 55. Hard or soft acceleration is
> the same. I haven't been under the car yet but will try today. I will
> also replace the vacuum line as that is easy and cheap and will
> eliminate a vacuum leak. I know the VM has been "adjusted" but without
> a gauge. Thus the need to make 2 so I can set it correctly. Where can
> I find the correct pressures? if Bently is for the early years. 

Sorry to be slow getting back to this. Things have been busy here 
again. I checked my Bentley manual again, thinking that I might have 
made notes of the late pressures in there. I see that it actually 
DOES have the correct late pressure in one place, but not at another.

Look on page 9 of chapter 8. The pressures are given in step 5. The 
only pressure I've ever bothered checking is what they call the 
throttle pressure, which for the late tranny should be 45.5 psi. 
That's what you watch when you adjust the vacuum modulator.

The '72-3 FI version of the VM is the C version. You might need to 
make sure that you still have a '73 AT in there. I have one sheet 
from VW that mentions a serial number for the early AT as being AB, 
so my GUESS is that the later one should be different. I haven't been 
able to find anything else on this.

On my '73 I've noticed that the vacuum line to the VM is complicated: 
It comes from 2 places and joins at a Tee. I don't think I've ever 
seen an explanation of what's going on here, but on mine, I've been 
tempted to replace those hoses since they wrap around the intake air 
runners and look like they've flattened over time. It makes me wonder 
if they are still doing what they were intended to do.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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