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Anyone familiar with A413 auto trans? Supposedly a 904 in a FWD case...


FBBO Gold Member
FBBO Gold Member
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7:30 PM
Dec 3, 2020
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western Maryland
Anyhoo, this is in my '90 Voyager turbo and I figured I'd ask here as well as on the turbo sites, to get a consensus. 3 speed non-lockup.

Van had an issue of wrong-gear starts for a while; would always start from a stop, in second. I'd drive around the problem by manually putting it in first, and it would drive fine. Fluid level and condition were good, nothing burnt, nice and pink. Then, one day...ALL it had, was first. No upshift. I could wind it out in first, lift off....and it would simply idle, even if I was going 30mph at that point. And about a week before it did that, it started flaring shifts a bit. And now, reverse takes forEVER to drop in. Fluid level and condition, still good.

I'm suspecting a valve body issue, and have been reading that accumulator problems could also cause this? (This is my first foray into an auto trans). So, right now, I plan to swap in a rebuilt valve body, and do a band adjustment (I do have a factory service manual).

I have a core trans disassembled on my bench right now, a) so I can learn the geography, and b) so I can clean/build the VB for a swap. Got it all apart, everything looks good, fluid in this trans was not burnt (it's out of a turbo car I parted years ago due to an accident), no metal, nice and pink. Worst case, if the trans in the van is full of metal shavings, I can swap trans' and be done with it. But I prefer to avoid the heavy lifting if I can.

Main questions are, though, about valve body mods, "shift kits", line pressures, etc. I'm lost. There are a couple of shift kits out there for like $45 - springs, plates, o-rings, etc. There are recommendations to remove a check ball. There are recommendations to drill a hole in a certain spot. I'm just trying to wrap my head around all this stuff. I know it's all hydraulic-pressure-driven, and the VB directs pressure where it needs to be based on throttle position, RPM, and load, and uses spring pressure on valves to do so...but beyond that? Stumped.

I just want to put together a reliable trans for the van. Snappy shifts, but nothing that slams you through the seatback or rattles your fillings. It's always had what felt like a sloppy converter; I'm hoping a band adjustment will take care of some of that (I don't plan to pull the pump or drums or anything).

Anyone have any advice for a newbie?

Once I have the van together and happy, I need to tackle the 727 in my wagon...it leaks from every orifice and shifts like crap. The 413 will be my teething trans, and I'll learn some theory here; the 727 will likely be a full rebuild, top to bottom, front to back.
Governor hanging up at first but without taking it apart and inspecting its anyone's guess. Those transmissions are very sensitive to any debris primarily bearing flecking. Go completely through it and clean it well. Replace all the bearings. Flush the cooler again extremely well and replace the converter.
Non electrical controls all Hyd like any other plain old 904-727 from days of old

But sure sounds like governor issues . And the flaring at shifts is a seal leak. Its coming apart. Sooner, or later is your choice
Yea it'll come apart. Depending how the practice run goes on the core, it may get a bench rebuild and swap in.

Sucky part is, I want to convert the van to a 5 speed...just can't find a console, or pedals. I have a shifter and trans and flywheel/clutch...

Who wants to bet I find what I need at Carlisle this year....AFTER I install a rebuilt auto trans? :BangHead:
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