[T3] Auto Trans Question

[Jim Adney]

On 22 Jan 2011 at 9:35, Tim Keohane wrote:

> I've a second issue/question. The tranny here has been inconsistent  
> when shifting, usually up a grade, and between 30-40 mph. Recently it  
> started to skip second gear and go directly to 3rd, and lug the motor.  
> To off set the issue ( till I can repair it ) we've been manually  
> shifting through the gears. When going from 2nd to 3rd if the throttle  
> is not let off the motor revs like the clutches are slipping.  That is  
> the only time there is any sign of slippage, otherwise the shifting  
> seems solid and there is no noise. The fluid is up to snuff, and not  
> burnt, nor discolored. I'll be changing the fluid, and cleaning the  
> screen to see if the problem is that simple. My question is: if the  
> trans was installed and the primary throttle pressure was close but  
> not "spot on", would that lead to pressure failures and symptoms as  
> described. I'm hoping I can adjust the primary throttle pressure ala  
> Bently and be back in business.

Not sure, but it certainly sounds like a vacuum modulator problem. If 
it just started doing this, I'd pull the hose off the VM and see if 
it's got red ATF in it. If so, replace and adjust the VM.

If not, as you say, you may just need to adjust the VW. 

The disturbing thing is that this is not consistent. Russ may have 
better insight into this.

My '73 AT has always slipped a bit between 2 & 3 under light 
throttle. Under heavy throttle, it shifts perfectly, but of course 
this is at higher engine rpm. I've looked at a number of things on 
this AT and never found a cause. So I'm stumped on this one, but my 
symptoms have been consistent for as long as I've owned the car (21 
years.)

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