003 transmission for a stroker engine

[Senor B.]

Hello,

I'm building a 2180cc for a 1970 squareback. I will post the specs in the engine-forum. I know to keep the cam on the small side (probably a JN40: https://frisiersalon-nowak.de/produkte/ ... ellen/typ1) so that the gearbox has enough vacuum to shift easily.

Are there other things to consider regarding the gearbox? Has anyone ever put a trans-cooler on 003?

[Piledriver]

Have one. Replaced a 4 speed. Worked great for quite awhile.
Had to park it for a dead R&P.

If the seal pops out or leaks between trans and diff (around the input/output shaft), ring & pinion life is measured in minutes. (mine popped loose despite red locktite)

The 090 is the same size... (no really, give or take fractions of an inch) but while admittedly heavier due to the steel diff case and much, much larger diff, can be built to take 800+ HP, and your 2180 will not make it break a sweat stock. Also Vanagon autos (at least the later ones) come with 2750 RPM stall converters. The 003s tend to come with 1800-2100 RPM stall units, VW eventually figured out that was stupid and caused overheated transmissions and cars that couldn't move if they had to move out of a pothole or over a 2x4.

The 090 has TWO seals back to back with an external drain in between where the 003 had that seal pop out.
VW fixed that stupid. 090 also has a choice of posi diffs and several R&P down to 3.21:1

I ran a megasquirted 1.8l T4 in it, that is probably being replaced with 100mm EMPI/Mahle birals x 71mm T4, with boost. MUCH better cooling capacity, used a Vanagon fan shroud and gas heater, has a diesel heater now.

The only downside of the 090 is the throttle needs to go through or at least connect its load modulator linkage on the RIGHT side (shift cable connects same coaxial shaft) good news is no vacuum signal needed.(same as Mk1-2 Golf, different diff setup, called an 010) A manual valve body is available and is ~required for very high HP apps.

[Senor B.]

Thanks for the detailed explanation. I never thought of a 090 gearbox. By chance, don't you have pictures of the conversion? Isn't the 090 wider which requires custom axles?

I've read about two seal conversion and external cooler with the 003 too, but I've never seen it done. It's still remains something of a "hearsay".

[Piledriver]

It is wider and the two axles differ (diff is offset on 003 and 090) ...But Vanagon automatic axles are correct for 090.
Pick up some outer stubs for t4 CV joints (AKA Thing stubs) and bolt it together.
I actually had to make custom stubs for the 003 trans, used a 914 axle on one side and bus axle on the other, converted the inner cv flanges to t4, made one flange 1/2" longer, already had thing outer stubs.

I could not source OG t3 automatic axles and wanted T4 cvs anyway.
T4 cvs are easily modified to fit T1/T3 axles: splines are same.
Counterbore the inside of the T4 spline area to same inner depth as T1 CV, you end up with a stock length axle with t4 cv joints.
This is far faster, easier and stronger than grinding the axles down to fit the cvs.

Switching the trans and building a new motor for the 73 are projects for this fall, Finishing the MS3 install on my Cabriolet (and keeping the Jetta going) are in front of it. Will take pics.

As to the old threads on the board, I still have some of them, rest were lost to a Western Digital "Green" drive raid array. long ago. (all the drives bought and died at same time, designed in failure) The rest eaten on the BBS at upgrades.

Still have everything, physically.