Type 3 Auto-Trans Diagnosis?

[MaximumFastback]

Hello,
I just recently purchased a beautiful 1969 Type 3 Fastback about 3 months ago. Two weeks ago, while driving 20mph in second gear, in the automatic position, the car rapidly slowed down without me doing anything, and the whole way home at about 5mph the car would brake(or whatever it is doing) every ten to 15 seconds. In several other attempts to drive it it has done the same thing again. When I describe this I say it is putting itself in park? Or perhaps rapidly downshifting into 1st.(I am no transmission expert by any means, just know how to adjust valves and carbs) A thing I do notice is that the car is usually at the top of its first gear when it happens. Any VW expert who could help me troubleshoot this problem would be much appreciated. I've been learning over the past months that the type 3 realm of support is a lot less readily available.
Thank you!
Max May

[raygreenwood]

So.....what have you done or checked?

Fluid level?
Vacuum line?
When was the last filter change?
Have you made sure this is transmission and not engine?
Have you replaced any seals?.....especially the one between automatic section and differential?
When you got this car did you check final drive oil to make surr its not comtaminated with ATF?
Have you done a band adjustment?

Do you have the brown Bentley manual?

Ray

[Mike Fisher]

Take your brown Bentley manual to your local transmission shop for them to use, if you need help with your 003 automatic transmission. Multi69s has also done this in depth transmission rebuild guide.
http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
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[ddare]

At the very least you should check your ATF level while the engine is running. When the ATF fluid gets low, I find that I have problems shifting (or even moving the car at all). It's a PITA to check because there's not a lot of leeway between the bottom fill line and the top fill line, so be ready to drain some out if needed. I also like to drain any fluids out of the vacuum line between the modulator and the intake air plenum as sometimes that fills up with oily crud.

[Multi69s]

"Two weeks ago, while driving 20mph in second gear, in the automatic position, the car rapidly slowed down without me doing anything, and the whole way home at about 5mph the car would brake(or whatever it is doing) every ten to 15 seconds."

When this was happening, did you notice a change in the engine RPM. If the engine RPM increased, then the transmission down shifted to first. If the engine RPM decreased, then the transmission upshifted to 3rd.

Ray's check list is the place to start. Always start with the simple 1st.

1) Get a brown Bentley
2) Check the trans fluid level
3) Check that the hose is attached (and in good condition) between the Vacuum Modulator and the throttle body.

The hose should be attached at the red arrow, where the Allen wrench is sticking out. This is on the passenger side of the car.

4) Then drop the transmission pan, clean the filter and check the color of the transmission fluid.
5) If the transmission fluid is dark, check back. If bright red, refill the transmission and try it again. I have noticed that the Bentley amounts, might be a little on the low side.

Hang in there and keep checking back. This Type 3 forum contains a vast amount of information and helpful people.
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T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
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AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

[gheezerghia]

Hello, I just purchased a 71 Fastback Automatic and had a question about the tranny. For starters, I have checked the fluid level and all is good there and the color was bright red. From what I’ve read that’s good. My first question is about shifting and how tranny behaves when shifting. When I put it into D or R ( the only 2 gears I’ve used) it engages with a thud. Not with a bunch of noise you just no your in gear kinda thing. After that all is ok until you come to a stop. The second question has to do with when I come to a stop. I’m assuming that a VW automatic would behave much like a new automatic in that when you stop the car is at idle and will creep forward if you let off the brake off? Correct? When I come to a stop the car will begin to vibrate as if it’s still trying to go forward instead running smoothly at idle. I’m hoping it’s just an adjustment? Any help would be greatly appreciated.

[KTPhil]

FI automatics are a joy to drive when all is well, but they are VERY picky about ignition timing and TOTAL lack of vacuum leaks. Without those perfectly set up, you will get a lumpy or high idle, which confuses both the FI and the tranny, and this will often show up worst at idle. Give the motor a tune-up including valve adjustment, point gap, timing, and go through ALL vacuum hoses. I recommend you just replace them all now and not worry about them later. Check the injector tip seals, too (hard to do in place, so you may as well pull injector pairs and replace them).

Remember the FI is not a modern closed-loop system that stabilizes idle. It is a "set and forget" or maybe "set and cross your fingers" system that does no idle speed compensation related to tranny gear selection. For this reason the free idle speed on an automatic car is 950 rpm, vs. 850 for the stick. Many find a little higher works more smoothly at a stoplight, even though it's a little higher than expected.

[gheezerghia]

Phil, Thanks for the advice. I’ll tune it up and go from there. Is there a good way to check for leaks without pulling all the hoses? Thank again

[KTPhil]

Unless you know they were replaced in the last year or two, it's really just best to make a morning of it and replace them all. Otherwise you'll chase them one by one as you try to figure out why it isn't running well.

Same advise on fuel line... messy job, 25 ft hose (5/16 gates barricade or others), about 35 FI clamps (not the usual worm clamps)... but then you drive with peace of mind!

[gheezerghia]

Hey Phil, Since we last spoke on this forum I’ve adjusted the vallves, timed it, replaced the cap, rotor, points, all the vacuum lines and all the fuel lines too. That being said the tranny shifts hard and when at a stop it seems to really want to move forward and the car vibrates and grumbles (for lack of a better term) when I’m at a stop. Typically I will put it in neutral when I’m at a stop to take the load off the tranny. I changed the little vacuum valve on the tranny because I was tol that if it had fluid in the line when you take it off that the valve was bad??? Other than that the only other things I’ve done are replace the the tranny fluid, the tranny pan gasket and changed the engine oil. After a drive today I checked the tranny fluid level and found it to be what I think is a pint low. I don’t believe I’m losing it (the tranny fluid, I’ve already lost it) I just don’t think I filled it to the proper level after I changed it. Your help would be greatly appreciated. Thanks, Gregg

[Dr Hilke]

Hi guys. Where do you buy Automatic Transmision parts?

[Tram]

[Mike Fisher]

[gheezerghia]

Hey Tram, Thanks for replying. I’m not sure what my idle speed is but I will have it for you a little later. Got a big list of things to do today and right now Millie (my Fastback) is on the South side of that list. Have a great day!

[Tram]

[gheezerghia]

Hey Tram, Finally got a chance to check the idle and it was money. It read about 910 and the dwell read 50 with the new points. The motor surges a little bit but other than that idles very nicely. I wish I knew how a brand new tranny behaved. I just do t believe it’s shifting correctly?? Are there any adjustments that can be made to the tranny? Thanks for your help.

[Tram]

[gheezerghia]

I’m up for the task. I know we’re dealing with old technology here but did these Trannys ever shift like today’s Trannys? Thanks again for the help.

[KTPhil]

They shifted very well. On light throttle, the changeover was smooth and more gentle. On hard throttle it was quicker and tight, just as you want it.

A FI automatic car needs absolutely zero vacuum leaks anywhere, good compression, good ignition advance, and dead-on idle timing. Forego platinum plugs, too. All these things can make it rougher if not right. But when it's all right, they are really responsive and fun.

[gheezerghia]

Thanks Phil. I believe I have all those boxes checked off. As I mentioned in my first post the car seems like the tranny is loaded up while at a stop,like you have your foot on the brake and your giving it gas. It’s not terrible but the car windows vibrate and it will start moving a little quicker than I’d like if I took my foot off the pedal without applying the gas. Is there a better way or fluid to spray to check for vacuum leaks other than staring fluid, brake clean etc.? I’m going to purchase the gauges and check the modulating pressure as Tram suggested. Do you have a thing else to add? I didn’t ask Tram if he had performed the pressure test (with his experience I’ll assume he has many times) but have you? Is there anything I should know that isn’t covered in the Bentley? Thanks for your help and have a good day!