Auto Trans shifting

[ClassicCamper]

Have a rebuilt auto on my 73 wagon. I must say, engine running pretty well these days.

Here is what is happening:

1) When car is first started and I take off 'cold', the transmission shifts as smooth as butter.

2) When engine is warm / operating temperature, the trans shifts a bit hard from 1-2. 2-3 is always smooth, actually it is barely noticable.

The hard shift from 1-2 isn't extreme, but enough to be annoying. especially since I am putting this car back together, bolt by bolt. I was poking around on the T3 forums trying to see if I can find anything out. There was a post which mentioned there is an allen adjustment in the modulator. I don't want to go adjusting things blindly. I know nothing about pressure(s) in the trans itself, and can't afford the gauges at this point. Can a make some tiny adjustments either way on modulator to see if it irons out the 1-2 hard shift OR

Any suggestions as to what may be causing this hard 1-2 shift at warm temp? Engine is tuned, vacuum is on low side if I recall. (Abt 11inHG ish). Otherwise trans works fantastic, R, D, downshift, braking, initial shift into Drive. It's really Just this 1-2 shifting thing.
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1973 412 Wagon
1976 Westy
1978 SB Vert

[raygreenwood]

Yes.....what is wrong...is what you have partially noted. If vacuum is a bit low.....it causes the main hydraulic pressure to be off in its relationship to rpm.

The allen screw adjustment is there partially to readjust the sensitivity to vacuum of the vacuum modulator valve. Less spring load makes it more sensitive to lower vacuum.

The other issues are age. With age and wear....the pump will put out a little less pressure as nd the fluid passages in the valve body will have some slight wear as well. This causes a fluid pressure drop on the supply passages....so it shifts differently.

When its cold....just like with the engine and motor oil.....the transmission fluid is thicker snd the passages and parts have not expanded with heat. So....the fluid pressures are higher. As the transmission heats up and expands.....you lose some pressure.

Yes.....you can carefully drive and tweak the pressure adjustment with a 4mm (I think its 4mm) Allen key. Clean around the valve carefully and use a sharpy to mark the starting point. Adjust maybe 1/4 turn at a time.

Make sure you are fully tuned up and perfect vacuum connections and valves adjusted before you start.

Ignition timing and advance affects this as well. The one thing I keep telling people also is that I have found through long experience (And Jake Raby did as well).....is that the type 4 engines.....and I am not talking about the bus here....which is a bit bastardized.....I am talking about 411, 412 and 914.....run and TUNE better with idle ignition timing with hoses on between 10° and 12° BTDC....never less than 8°.
This idea of running advance out to its max at specifed rpm (in our case 27°BTDC at 3500 rpm).....that part is correct.....but the statement "and let the idle timing fall where it may".....is pure bullshit.
This is not a beetle with a 34-pict 3 carb.

D-jet on these engines went through pains to set injection timing location and have good off the line throttle response. In fact....the models with dual vaccum advance control.....use that control partly to make sure that idle timing is stable. Ray

[ClassicCamper]

The shift lever indicator broke:

Placed a WTB ad a few times with no bites. Suggestions? Can I fix mine above?

Thanks, Ron
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1973 412 Wagon
1976 Westy
1978 SB Vert

[raygreenwood]

That part gets brittle....either styrene or acrylic. A solvent melt type adhesive for acrylic should work. Most hobby shops sell this adhesive in little bottles with a drip needle applicator. It literally melts the plastic back together.

I might have a spare but it will be mid week before I can look. Ray

[raygreenwood]

I hate it when they lock threads like that. I was in the middle of typing when it got locked. Bad Everett!


Unlike most of the rest of the forums around here...which are basically online, VW related "trailer parks"....full of the automotive equivalent of wife beating meth tweakers...the 411/412 is a bit more sedate and to the point with regard to knowledge and questions.

Shutting down a question like that....shut down THIS type of discussion that follows and is useful to 411/412 people

Toward your search for a new shifter bezel indicator scale:

I have a complete shifter housing somewhere. I was keeping it in case I ever needed to go back to an automatic if the parts for manuals dry up (any more than they already have)

OK...the part number for this little bezel is 311 927 135. As can be seen, the shifter is a type 3 part...however...its not totally type 3 all the way through.

That knowledge alone should widen your horizons for a part search


There was an early and a late type 3 automatic shifter. The early one was a bit different.

While the start inhibitor switch and all switch plates inside are all type 3 part #'s....the shifter plastic housing, the shifter mechanism itself are type 4 specific. This is why ...unlike the type 3, the type 4 can start in park.

Here is an early one from the classifieds in the type 3 parts section so you can see the early shifter.
http://www.thesamba.com/vw/classifieds/detail.php?id=1976356

Here is a complete late auto shift cover...most of whose parts will work on yours...especially the parts you need...but at 45 pounds plus shipping....a bit pricey.

http://www.thesamba.com/vw/classifieds/detail.php?id=1960992

As for repair...as I noted in my last post in this thread...this part is either acrylic or styrene. A solvent melt type liquid adhesive from any hobby house or plastic company...in a needle dripper bottle WILL fix your part pretty permanently.

I will see if I can find my shifter housing this week. In the meantime...try to repair what you have. Typically any solvent melt adhesive that has a mixture of tetrahydrofuran and acetone will do the job.

I have this adhesive....and it works pretty well. It is especially good for joining totally different...but similar...rigid/crystalline plastic....like ABS to styrene and Acrylic to ABS etc.

http://www.traintekllc.com/plastruct-plastic-weld-2oz/?gclid=CPH_ptey29ACFUYbaQodFi8K-Q

http://www.traintekllc.com/tools/dispensors/

You will need to get a small dispensing bottle with a needle. This one is rather large. Get one smaller than .040".

This ad hesive is water thin. Just a small droplet on the cracked area will spread over the whole surface in a second. I wet both surfaces just lightly. DO NOT use too much as it will squeeze out of the area when you join it...and it WILL instantly ruin other surfaces.

I use the needle to wet one surface...and the brush in the cap just to dampen the other surface. Practice first...your move to join the two plastic parts...so you are smooth...and make a prop area to lay the part so it will not move until its fully dried....which will take a while. But once it is dry...the joint will be as strong or stronger than the original plastic. It literally melts them together.

Ray

[KTPhil]

[SBD]

My wife had a 1971 Squareback with an automatic. Maybe somebody had jacked with it but it would start in neutral or park. It had been converted from FI to a set of factory dual carbs if that would have anything to do with it but it was a bit of a hack job. No kick-down switch & cheap chrome air cleaners. And as I recall they had just cut the harness coming from the FI computer.
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"Just $99 down and $64 a month for 36 months buys you a brand new Volkswagen Beetle!"

[raygreenwood]

[KTPhil]

I am guessing VW changed the electrical contacts at the shifter to allow starting in Park, and that part could have been retrofitted to a '71. Or maybe the change actually came in late '71; I am going off the Owners manuals for the change, but that isn't always 100% correct. If someone has a late Progressive Refinements or a parts list and some time, this could be nailed down.

My '71 automatic fooled a valet years ago when he sheepishly came back and said "your car won't start." I told him to start it in N, and he looked at me funny. Came back with the car, though.

My Prius fooled a lot of folks early on. The START button was not common back then, and the electronic shifter was also "different." Toyota actually provided a pad of "How To Start" cards to hang on the shifter so valets could work it.

[raygreenwood]

[titan3c]

Mine is a 71, and starts only in neutral. I think that can be changed with a later switch part. The part the shift lever makes contact with for the start, and back-up lights. I noticed on that part(must have been a later one) there is a connection point for park, neutral and back-up lights. If one wished to have start in park I think it's just a matter of changing that part. A simple change, if you can find the part.

I discovered this when I ordered a replacement part because mine was so worn it wouldn't make contact every time, and I had do a by-pass switch deal on the side of the gear shift bezel so I could start the car when the gear shift wouldn't make contact. The new part arrived, and I rejected it because it had the extra contact point, and thought it was the wrong part. Dumb me, if I had just thought about it awhile I would have known what the extra contact was for. Just another "Duh" for me. Bob

[mtsackid]

For those of you with experience driving a 1974 412 automatic transmission, do you always feel a hard shift going from 1st to 2nd gear? Or should it always be smooth whether the engine is hot or cold?

I got to drive one the other day that had sat for a while and it didn't feel right to me. I had a chance to buy it but it gave me pause.

[titan3c]

I own a 71 411 four door sedan which I've owned since new, and it has always shifted smoothly with just a slight feel when it shifts. I'm not an expert on automatic transmissions, but a firm notice in the shift would be OK, but of course a hard jerk would not be OK. Someone else can give you a more knowledgeable comment. Bob

[raygreenwood]