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Posted by: streetrover Jun 26 2015, 04:56 PM

Hi guys,
Any of you 901 experts ever modify a rear-shift trans to fit in a 911/912? I assume a bit of machining and fabrication could accommodate the shifter shaft. What about "flipping" the ring gear?

Bob

Posted by: andrew15 Jun 26 2015, 05:01 PM

You can flip the ring gear, but would probably need to reset its tolerances - diff bearing shims and pinion depth would need checking / changing I would suspect

As for the shift rod, you can replace the 914 shift rod with a 901 version and fit the 901 nosecone

Regards,
Andrew M

Posted by: Dave_Darling Jun 26 2015, 05:55 PM

Or you could get a transmission from a 911/912 up through 1969, which is exactly what you're describing.

--DD

Posted by: screenguy914 Jun 26 2015, 11:41 PM

901 gearboxes std. equip. up through 1971. '72 was the first year for the 915 box.

Sherwood

Posted by: oldie914 Jun 27 2015, 02:33 AM

I've converted a few 914 transmissions.
To convert a tail shifter, you need the 901 nose piece and long shift shaft and if you want to use the speedometer drive, you need a 901 angle drive and the brass gear piece for the pinion shaft. If you don't change the speedo drive pieces, it will run backwards.
Pinion depth is not affected by conversion but the ring gear backlash should be checked. I have found that the backlash for the flipped ring gear is often OK.
You also need to move the vent on the top of the case to the 901 position.

Posted by: Dave_Darling Jun 27 2015, 11:37 PM

70-71 had the "911" gearbox. Basically a 901, but with a revised clutch mechanism. That's not quite the same thing.

--DD

Posted by: streetrover Jul 12 2015, 09:04 AM

I have the stock 4-spd trans in my '69 912. I've converted 912 to a type 4. The stock trans doesn't have very tall gears. On the freeway I'm tach'in pretty high. I really like the gear pattern in my 914 ... nice tall 5th gear. I have several 914 trannys sittin' around. Just thought I'd use one of those.