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Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Wed Jul 05, 2017 12:28 am
by Piledriver
There will be pictures. I promise.

Installing a T3 automatic (3.69 R&P) and beefing it a little, $500, rather than spending $5-6K on a fully beefed T1 trans/clutch that probably won't last 5K miles anyway with a blown 2.5L T4 hanging on it.
Got everything from the shifter to the axles for $300, plus master kit w/frictions and custom trans bands, just under $500 once I fill it with Redline D4. Using a handy 86 Vanagon converter with 2750 RPM stall.(simply fits)

It may eventually get an 090 with a taller R&P if I kill the 003 too many times, but I can afford to do that a few times considering how cheap the parts are and how easy they are to work on.

Good news:
The front mount is there and like new.
It bolts right in, and I have the correct automatic axles to match.
The trans looks pristine enough inside that it went right back together and is initially going to be installed and tried after only replacing all the potentially fatal-to-the diff seals (front and rear pinion seal, and governor shaft seal).

I have the whole master kit, lovely carbon metallic bands from Alabama Transmission Bands, and Attomatic (Raybestos) green semi-metallic "High Energy" frictions for when I actually do the full rebuild, came as part of the master kit from Cobra Transmissions, and strongly recommended for use vs.having them relined with carbon metallic by Alabama Bands.

Bad news: Car has early 944T aluminum trailing arms that take Very, Very Long 944T//Vanagon axles.
I am extremely disinclined to revert those mods (custom coil over shocks, modded mounts, huge brakes, 944t wheels)


Just spent the last couple days yanking the perfectly good engine and manual trans out of the sguareback and working on how to install the automatic----while retaining the 944T rear arms etc.

Also hopefully doing something like a frame horns/kafer brace setup so I can ditch the rear crossbar, which interferes with some stuff I want to try, like test out the dry sump setup on a the all-used-parts 1.8L etc. (It may get some handy 96s while its out)
The rear crossbar may just get some rework for clearance if all else fails.

As to the trans itself, It's doable, given some work to the drive stubs, and a custom axle for the drivers side. :twisted:

I was originally going to JUST offset the trans/drive flanges, as the motor doesn't have a seal around the outside, just on the air intake or the fan. BUT---I'd really prefer things on centerline, so I started looking at alternatives.

For the passenger side (long axle) the solution appears relatively easy, esp as this is an early trans with the drive stub retention flanges, and I need to weld on some T4 flanges anyway.
Turns out the thickness of a dead T4 CV joint body is ~perfect, so I will weld a dead CV outer to the flange, grind to perfect thickness on the lathe as needed and install helicoils or timeserts in the existing holes, which oddly happen to be the ~right size and place for inserts...

For the drivers side, there is a larger problem... or simply: It's FAR easier to extend a drive flange than make an axle shorter.

After a bit of Google-ing for axle lengths and raiding of my personal parts cache.... Turns out a 914 axle appears to be ~the perfect length, 20.25", just a 1/4" shorter than a short vanagon automatic axle.(latter might also be right length)

I just have to counterbore the splines of the T4 CVs so they slide on far enough to seat the snaprings, needs about 3mm, maybe a little less., basically open up the factory countersink a bit deeper.

The original trans drive stub will get turned down a bit and mated to a machined German t4 flange then welded, small bit of length adjustment possible at this point if needed.

The retainer flanges were ~20mm deep and the 90mm flanges spun within, but now they are ~5mm thick so the larger t4 flanges have plenty of room. The bolt pattern is ~5x110, so a small axial groove on the OD of the flange will provide sufficient clearance to get the flange bolts in/out, now flathead machine screws countersunk in.

For reference: Some data from, some my tape measure
T1 axle=16 5/16" 28mm splines
944 axle= 16 1/8" (need to verify, may be same as 181)
bay bus manual axle 18 3/4" 34mm splines (some space taken by spring cone washer)
914 axle (manual) 20.25" t1 depth splines but cv joint splines can be relieved inside for std length, or outside as needed to adjust assembled length, can be std, ~+3mm or +6mm. Same trick works on T1 axles.
vanagon manual trans/944T axles 21 1/2" (need to verify)

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Sat Jul 08, 2017 5:41 pm
by Jadewombat
I had some custom length axles for my T1 SSC into my '66 bus from an offroad place, don't remember which one but both were equal length of course. Aren't the T3 autos axles unequal length IIRC?

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Sat Jul 08, 2017 7:53 pm
by Piledriver
The T3 and Bus 003 or 090 vanagon autos all have unequal length axles.
The transmission is on center, but the differential is offset to clear the large automatic coaxial input shaft and pump drive etc.

I just basically had to deal with the new custom lengths needed for the 944T rear arms etc, which take a pair of long Vanagon axles from the factory, the stub axles at the outer end are very short compared to a ACVW, it uses the std sealed dual row bearing like most Porsches and a great many FWD cars, later Porsches use the same bearing up front in 2WD or AWD configurations.

I have half corrected the offset with a passenger side drive stub extension, but the drivers axle is still about 30mm too long if the trans is mounted on center as desired.

The shorter drivers side 914 axle (with a little quality time spent grinding on the T4 CVs beveled end) allows the trans to be centered in combination with the passenger side vanagon axle and drive stub extension (basically a welded on t4 CV outer shell, with threaded inserts).

So L axle is 914 with slightly modded T4 CVs, R axle is Vanagon manual trans (R axle same as std 944 Turbo) rear suspension is 944T. Trans/bell housing is on centerline.

Some might be concerned about the slightly smaller T1 CV splines, but I have never even heard of factory axles and Lobro CVs splines stripping in any use. I'm using all factory axles and CVs.(just not for a T3)
No EMPI parts here.

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Sun Jul 16, 2017 2:44 am
by Piledriver
New extended length drive stubs, about 4MM longer on the short, ~28mm wider on long one.
This centers the trans perfectly with a 914 axle w/modded 944 CVs and the std (for a 944T) Vanagon (manual trans) length axle on the passenger side, with proper offset axle lengths for the 944T arms and automatic..

The long one got a complete T4 CV outer welded on, the CV body got partially turned to the same OD as stub, which had the lip turned off, and both deeply V-cut to match to allow for a good, deep weld. Flowed them together while clamped with TIG, welded nice, 2 more passes with std carbon steel TIG rod, no evidence of cracking etc, then MIG pass on the ID simply to seal the cup, as I left the somewhat overlapping bolt holes open. I installed 8mmx1.25 mm helicoils in the bolt holes, which was interesting due to the hardness of the CV bodies towards the middle. There wasn't quite room for timeserts.

The short ones T4 100mm drive flange was sacrificed from a dead 002, the remainder still keeps things sealed up on the 002. These proved a bit more difficult to weld, as simply TIGing the machined press fit bits together (even with preheat) had a crack follow me around. Ground that out a bit then TIG using 347 SS rod. Ground much of that back out to verify no cracks/voids etc.

Everything got a long bath in phosphoric acid and wire brushed to make pretty, rinsed, dried, then simply hit with Break Free.

These early style stubs are retained with a circlip/thrust washer to the 5 bolt aluminum stub/seal carriers, the outer flange turned down from ~16mm to ~5mm, countersunk, and SS flat head machine screws used for retention to provide clearance for the larger t4 cvs. (the T1 CV drive cups ran inside the and flush to the outer surface of the unmodified seal carriers/retainers.)

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Mon Jul 17, 2017 10:57 pm
by Piledriver
New motor mount setup on the Bay bus crossbar, much like the old one, but based on 914 mounts for added strength/stiffness and the ability to get the inlet and outlets lines to/from a modified CB drysump pump (not on this motor, the new one will get that)

Inner L mounts are std 914 rubber and metal, R mount has L side wall removed and has an over-the top support added to allow passage of the 3/4" ID pressure stage inlet hose.
The welded on "wings" hold Vanagon outside rear mounts to prevent twisting.
They are largely made of the old, dead mounts.

Those also limit max engine roll/side to side motion with folded over steel tabs, even if the 914 mounts come apart.

They are not as preloaded as the 914 center mounts, which do most of the "holding things up" work. This setup raises the engine about 1/2" (some simply due to new mounts) and moves the motor back a bit relative to the bar to provide room so that the AC pulley doesn't ever kiss the crossbar.

(it really only made contact due to shot motor mounts, they were ~OK used when I built it 90K miles ago, but I wanted provisions for the DS setup. The automatic is also a touch longer with the stock front mount)

The crossbar is hard mounted on shortened Bay bus mounts bolted to the T3 mount consoles via some steel tube 2x4s.

Sorry for the one photos odd angle, the forum software seems to insist on landscape orientation...
Last pic is old setup (when new) kept for later use.

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Sun Jul 23, 2017 3:12 am
by Piledriver
How to kill an evening, thanks to a PO or some idiot mechanic... I wanted to stuff the engine and trans tonight to make sure everything worked...
At least the Vanagon converter is now in place... ... 0&start=52

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Mon Jul 24, 2017 5:57 pm
by Clatter
Love it!

Pictures! :shock:

Did you ever look into automatic 944 axles?
IIRC, they are different lengths on the autos.

Interesting how aftermarket axles come with no inner shoulder to seat against the CV.
The snap ring at the outer, or captivity, to hold them in..?
SOP seems to be to just let them float?

I'm too lazy to re-size right now...

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Mon Jul 24, 2017 6:27 pm
by Piledriver
On the 944 auto axles, I'll research their length, but I used what was handy, so it was probably a win.

Yes, the off road folk let the long spline aftermarket axles float, which tends to punch holes in the drive cup seals.
I made mine a tight fit, I'm not using the ~18" of theoretically possible travel anyway, although it probably has 10, most of which is never used..

Didn't get much done yesterday, WAY too hot and humid, and when I did poke my head out the thunder/lightning/rain promptly began.
Back at work this week, so it will be an hour or so in the AM here and there for awhile.

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Thu Jul 27, 2017 4:42 pm
by Clatter
When you gonna do a build thread already! :wink:

Good thing I been poking around the whole site lately,
I get to see your brakes in one thread, axles in another... :P

I'm surprised you used the rubber mounting at the case, and solid at the ends of the bar.
Opposite of the 911 and late type 3..

Rubber at the case was used when the motor hangs from the top of the bellhousing.

You don't get wheel hop after you come out of the burnout box when running slicks?

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Fri Jul 28, 2017 3:20 am
by Piledriver
Not really worthy of a build thread, its been a series of small mods, spread out over many years.

Considering all the lost photo issues over the years though, might be a way to get everything linked into one place with all the pictures.
I considered 911 mounts but the load doesn't line up well with the center of where the factory mounts were, so the solid outboard setup works better, and required no non-reversible mods.

I don't own a set of slicks, but 911s of most years have (fundamentally similar) front trans/rear engine mount and nothing in between and no wheel hop.
The trans and engine are pretty rigid, unlike frame horns in a T1, which like to get all wound up and twisted.
914s seem to have no wheel hop issues either.

If i do run into any wheel hop, I'll look at triangulating everything.
I was planning/// would have preferred to ditch the rear bar, but didn't see an ~elegant way to incorporate the tubular (EDIT) frame horns I have with the automatic, thus the redo on the rear mounts based on modded 914 mounts set up for a CB drysump (I made those ages ago)

That setup actually worked very well until the mounts fell apart, the 914 inner/Vanagon outer mount combo should work even better.

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Mon Aug 14, 2017 12:05 am
by Piledriver
Spent Friday doing a "make clean" on the ECU/engine wiring, now ~tolerable quality, no longer a rats nest.
It will probably never be "pretty" unless I yank it all out: One of the reasons it looked iffy was it was set up to be pulled through conduit (boat bilge pump tubing), with minimal rework. plus I had modified a bunch of stuff over the last ~3 years.
There is also a LOT of MS3X I/O I will probably never use in this car unless I do the dual plug and staged injectors setup in this car... That's probably going to happen when it all moves to the 914.

After the torrential rain yesterday (almost filled an empty Homer bucket I inadvertently left out :shock: ) I squished my way over to the driveway, threw down some plastic cardboard and plywood for a dry surface and rehung the cooing air intake and exhaust system with plenty of anti-seize.

Once I hung the exhaust, I redid the ground cables at the battery, moving the "to car" one inside under a rear seat belt mount... Hooked up the battery, turned the key and shockingly it fired right off on all 4, which was something of a pleasant surprise, as I had lost track of which coil connector was which so there was a 50/50 chance on each side being right.

Car is still up on stands, but the transmission appears to transmit as requested, and in the requested directions.
It does dribble some ATF from the governor housing as the kit did not appear to have an appropriately sized oring in it, or at least not one that wasn't labeled for something else.

Still need to hook the backup lights, run the starter interlock through the shifter, and I need to set up an I/O and wire up my last free relay on my MS setup for the trans kickdown, but it seems to be alive.

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Sat Aug 19, 2017 10:12 pm
by Piledriver
After a week of daily rain, including some serious downpours, I sloshed out to the driveway this afternoon, re-re tightened up the CV joints, popped the right oring in for the governor cover (not the "correct one" but one that fits) and filled up the diff with GL5 after checking that it had not gotten any ATF dribbles... Popped the tires back on and took her for a short loop around the block so to speak.

Even with the kickdown wire not connected, it shifts properly at all loads, at ~reasonable RPMs, so the modulator valve even works.
It has a nice crisp 1/2 shift, with more motor it might even chirp the tires.
I need to target the idle speed a little lower, and I'll probably shorten the shifter a couple inches, as I have Corrado seats, which are probably 3" lower than stock.

It looks like its going to stay dry for a few days, so I'll hook up the backup lights, kickdown and neutral interlock tomorrow, and it will get inspected/renew registration and back on the road next week.
(reg expired end of last month, thought I would be done by then)

I guess I need to keep my eye out for an automatic pedal assy or mod mine.

Re: Installation of an automatic _into_ a T3.. factory did it, easy, right?

Posted: Tue Sep 12, 2017 7:14 pm
by Piledriver
Have been driving it with no issues, other than I still need to hook up the kickdown solenoid relay to a programmable IO.
Manual shifting is relatively instant though, its not a slushbox when manually shifted, unlike a lot of automatics.

Surprisingly, my fuel economy seems BETTER than with the manual on the highway.
It turns another ~150-200RPM in 3rd, but the motor is running in a happier place, and runs much lower manifold pressure at cruise.

Trying to track down another convertor to have modded to a ~3200 RPM stall as this one stalls at 2K.