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I would think that there are two criteria for a fit. One is of course physical in that the convertor must fit all the shafts, bushings, and seals, as well as the starter. And the other is operational, the H specs look about the same as a Z, but the Waterboxer Vanagons had watercooling for their trannys so there may have been a heat issue to deal with. I really have no idea on the fit, but would love to find out someday.

Aaah, so you're saying that the tranny may run hotter with some than others. Thats the part I did not see before ( I know nothing about AT's).

The H is not listed for use with air cooled engines, I do not know whether it runs hotter of not, I do not know whether it will interchange at all. Rebuilder which list all the different coded torque convertors for the Type 4 engine under one single part number list the H seperately for the watercooled VWs, this doesn't mean the H won't fit an aircooled, but it doesn't in any way guarentee that it will. According to VW (and some other sources) the Z which was listed for the later 2.0 L Type 4 VW's should run cooler than the earlier convertors like the D and K convertors . VW recommends that the Z be swapped for earlier convertor for improved drivability and cooler running. My Z is doing great, lots more torque at lower speeds and no evident overheating.

That's great. And.......... how do you check for overheating?

With a transmission fluid temp gauge. I've been toying with putting one on my 412 when I get it going, since the only cooling that happens is the air going past the TC stirred up by the fins. Seems like a good idea to me.

With most WC designs, the engine coolant temp gives you a rough idea what's up in the AT, since most have an oil-to-coolant heat exchanger in the radiator, though some don't...my old '85 Voyager had a separate oil-to-air HX in front of the radiator, as an example. I wonder what the Wasserboxer busses had for AT cooling?

BTW, if the "H" TC doesn't have fins on the outside, it's not suitable for use in the Type 3 AT (the one used on 411's/412's, Type 3's, and air cooled busses). The fins are the only thing that moves air over the surface of the TC, and that's the primary heat exchange surface for the entire transmission.

, Thanks for the enlightenment. The guy at the TC shop lined up the ones he had (K & H, and my D) and there was no visible differnece at all, fins or else. I guess that means that they all would work on our motors