Felix asked me to take apart the tranny and inspect what is now second gear (it's a 4 speed now for a V8 conversion car).

I knew it had taller gears..but I had NO idea it was a 100% custom box. I took pics of a stock tranny and did side by side shots. I also counted the teeth on all the gears to document exactly what Felix had for his car. I'm guessing this tranny cost about 2500$ to build with the custom R+P and the custom mainshaft.

The above shot shows the pinion gear.. count the teeth.

The shot below shows the tall 901 1st gear (part of the mainshaft) which is now first gear in the "tall" box. Look at how the gear is MUCH smaller on the tall box (11 teeth which makes it a "A" mainshaft) compared to the shot below this one of second gear on the mainshaft.

Stock second gear in a stock 901 box.

It goes like this (from what I can remember)

A :for what is now 1st gear
H :for what is now 2nd gear
Q :for what is now 3rd gear
ZD: for what is now 4th (ZD is a stock 5th ratio)

how do you keep from accidentally putting the shifter in the old first position - and if you did could you drop the 1st/reverse slider off its hub inside the trans?
I had someone ask me if I could block out that position with my shifter - it would be easy with a steel plate between the base and the shifter body.
What are your thoughts on that?
James West

It is most reliable to put a spacer collar on the 1st/Rev shift rail, that fits between the feature on the shift rail and the pinion bearing bulkhead.
This is foolproof, blocking the shift rail from going beyond the neutral position to where 1st gear would normally reside.
It might work most of the time by doing it on the shifter, but is guaranteed to work every time with a spacer collar on the shift rail.
Hayden PTBT

Pictures of the lockout tube procedure with tube:
Mueller

This is the way I bought the transmission, I never used it since I sold all my V8 conversion parts. The tube is just a simple piece of galvanized water or gas pipe.
Mueller

Mike / James
The spacer collar is even more reliable if it is arranged down inside the maincase section of the transmission - between the socket feature on the shift rail for the dongle and the pinion bearing bulkhead.
The photo shows the 1st/rev shift fork being used for the shift rail abuttment of the spacer collar, meaning that any force attempting to select 1st gear (might be a missed attempt at 3rd) will be trying to move the 1st/rev shift fork along the rail - an arrangement that can be avoided.
Hayden PTBT

Hayden, the way it is pictured could cause the fork to slip on the shift rail. You are saying to put it at the other end of the rail (closer to the flywheel) so it contacts a forged-in part of the rail rather than a moveable one.

Did I get that right?
James West

James,
That is correct.
A pic would help - but effectively at the other end of the shift rail as shown in Mikes photo's. The end of the shift rail concealed inside the maincase.
The neutral detent automatically holds the shift rail in neutral, so the spacer collar can be manufactured to suit the calculated gap between the forged feature of the shift rail and the bulkhead that separates the differential from the gears.
I would make the spacer +0/-1mm to the calculated gap.
Gap must be calculated as the detent is in the intermediate plate.
Hayden PTBT

The only way for the shift fork to slide on the rail from the force of the added tube is if the screw is removed completley.
I'm not in any way disagreeing with Hayden, just pointing something out
Mueller

1- removed (A) 3.09
2- same (F) 1.89
3- 4th flipped ® 1.08
4- 3rd flipped (Z) 0.79
5- 901 2nd gear flipped (?) 0.59
Chris914n6