VW auto transmission - no drive

None I know of.

Probably a silly question, but have you checked the fluid level after running the engine? The torque convertor has to be filled up and this could have dropped the level below the pump pickup.

Gets my vote. Most people don't realise that many autoboxes require the level to be checked with the motor running.

I don't know the VW unit, but for Borg Warner units the gearbox and torque converter have to be filled from the same filler. So when you put the fluid in, does it go into the torque converter and then into the gearbox, or is it the other way round? Because if you fill the gearbox first, there won't be enough fluid to also fill the torque converter, and you will have to have a couple of goes topping up until the torque converter is full.

There should be a fluid connection between the torque converter and the gearbox too. Are you sure you aligned everything so that this connection is not blocked? You won't get any drive unless both the torque converter and the gearbox have the correct fluid levels.

Finally, have you checked the fluid level with the engine running, after placing the selector lever in each position for a short while to expel all the air from the connecting oilways? It usually goes down a long way from the level you fill it to when stationary, and the final level is reached after about 5 minutes with the engine running, and this is when you should top it up to the correct level.

Jim

I'll be suprised if it turns out to be anything other than incorrect fluid levels.

Thanks folks

It might be to do with that but when I first checked it was in fact too high on the dip stick. I've drained it all out and refilled to the correct level and also tried it at various other levels and it's not biting.

This box is supposed to be activated by engine speed and has no electrical or vacuum connections. The only other thing I've disconnected is the accelerator linkage which goes via a lever on the top of the box, though I don't think it's relevant. However that's my next move.

when you put the TC back on, did you rotate it while fitting and pushing, so that it engaged with all the internal bits? after refitting the engine it should have been necessary to pull the TC up to the flex plate, did you pull it out? or was it already touching ? If it was touching straight away then it might well be that it never was engaged with the pump, in which case it will never start pumping and never drive. I haven't done this myself, but I do know someone that did (on a ford). Another possible is if the flex plate was removed and there should be a spacer which has been left out.

They all use a mixture of engine and road speed to partially determine gear change speeds. The other thing which determines this is...

Which acts on the line pressure from the pump. Now I would expect this to not allow that pressure to go below a set minimum - but before going further connect it up and adjust correctly.

Don't know this box but on all the ones I've worked on the tangs which drive the pump are so long that you'd not get the box bolted up if they weren't engaged correctly.

You would be amazed at what people manage to do, I have seen clutch plates in backwards, cambelts routed wrong but the engine still runs, battery leads reversed, lhd headlights fitted in rhd vehicles, bulbs upside down, brake pipes cut and crimped over, thermostats in backwards, disc pads in metal side to disc. etc. etc. Wrong wheels that rub on the struts. Wrong wheels that cause the studs to bend and snap off. All owner induced faults.

Oh indeed. But in this case - unless the box is very different from any I've worked on - the tangs will be about an inch long, and unless correctly located the box simply won't fit home to the bellhousing by approx the same amount. And very few would think this ok. ;-)

I came across one like this. I don't know if it was the dogs not engaged or the converter nose not sitting in the crank but the chumps concerned had managed to get the (long) bellhousing bolts to start and just wound them fully up regardless. This buckled the flex plate and the starter would not engage the ring gear properly! No damage to the box however.

Julian

=A0 London SW

OK more follow up. I'm trying hard to do everything other than taking the engine out again. I just went and uncoupled the drive plate from the torque converter. My transmission has cut outs in the bell housing so you can spin the TC by hand. It was very smooth running and was lined up so there was maybe a mm of play back and front after the bolts were removed.

No grating sounds like it wasn't engaged properly. But what was noticeable was a gurgling sound like the TC was only half full of fluid. This suggests either a blockage so fluid isn't getting through or the pump isn't working.

I've also had a look at the accelerator linkage, but this doesn't seem to have anything to do with it other than have a pivot on top of the trans. I don't think it controls anything inside. That said, the kick down is supposed to come through the accelerator pedal, so I'm still looking.

You are sure you've got enough fluid in it? & that you put the stator back in the right way round?

Sorry, outlook distress has stopped indenting :-(

No grating sounds like it wasn't engaged properly. But what was noticeable was a gurgling sound like the TC was only half full of fluid. This suggests either a blockage so fluid isn't getting through or the pump isn't working.

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No, the converter will always drain down to half full when stationary, it's a normal feature of all the autoboxes I've come across. It fills in a few seconds after you start the engine. On a Chrysler box it fills best in neutral and not park. have you tried this? Also you may need to move the selector through the full range slowly to purge air from the valve block.

Go and try again, is there enough fluid in it, remember that fluid level is checked (normally) with engine running and box in neutral.

Sometimes the seals on the brake band and clutch pack actuators harden up through age and leak resulting in a no drive situation - some additive for autoboxes may help if the box is on its last legs.

Julian.

Julian.

I hate to point you at it, but this sounds exactly like your problem:

this sound possible? " If the converter isn't indexed into the pump gears properly upon trans or engine installation there isn't enough room for the converter. Meaning negitive clearance when there should be "some" clearance.

Tightening up the engine to trans bellhousing bolts preloads the torque converter into the pump, pressing the pump gears into the pump with massive amounts of force. Immediatly upon starting the pump gears either break up, or the pump gears wear into the pump sending large quantities of metal throughout the trans. First place is into the valve body to the pressure regulator then the converter is charged, then the oil exits the converter and flow through your cooler. When you try to put it in gear the oil is sent into your clutch packs."

Crikey.

It never ceases to amaze me what some will do.

That sort of suggests the transmission was removed - and replaced - with the TC in place. Not recommended, although plenty do it that way.

Yes some of this is familiar, but it's not been necessary to force anything. It all fits and turns smoothly and there haven't been any nasty snapping or grinding noises with the engine running.

However... when I was taking the engine out I did get it back a couple of inches before I discovered where to unbolt the TC. Also on putting it back and with the drive plate and TC still separate, there was a bit of a clang which sounded like the drive plate getting stuck then freeing itself. Don't know if that could have bent something.

It all worked fine before I pulled the engine so the fault is one of my own doing, even though the box is probably fairly well worn.

to be continued....